Mechanical Ventilation 7th Edition Cairo Test Bank Chapter 01: Basic Terms and Concepts of Mechanical Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The body’s mechanism for conducting air in and out of the lungs is known as which of the
following? a. External respiration b. Internal respiration c. Spontaneous ventilation d. Mechanical ventilation ANS: C
The conduction of air in and out of the body is known as ventilation. Since the question asks for the body’s mechanism, this would be spontaneous ventilation. External respiration involves the exchange of oxygen (O2) and carbon dioxide (CO2) between the alveoli and the pulmonary capillaries. Internal respiration occurs at the cellular level and involves movement of oxygen from the systemic blood into the cells. 2. Which of the following are involved in external respiration? a. Red blood cells and body cells b. Scalenes and trapezius muscles c. Alveoli and pulmonary capillaries d. External oblique and transverse abdominal muscles ANS: C
External respiration involves the exchange of oxygen and carbon dioxide (CO2) between the alveoli and the pulmonary capillaries. Internal respiration occurs at the cellular level and involves movement of oxygen from the systemic blood into the cells. Scalene and trapezius muscles are accessory muscles of inspiration. External oblique and transverse abdominal muscles are accessory muscles of expiration. 3. The graph that shows intrapleural pressure changes during normal spontaneous breathing is
depicted by which of the following? a.
b.
c.
d.
ANS: B
During spontaneous breathing, the intrapleural pressure drops from about 5 cm H2O at endexpiration to about 10 cm H2O at end-inspiration. The graph depicted for answer B shows that change from 5 cm H2O to 10 cm H2O. 4. During spontaneous inspiration alveolar pressure (PA) is about a. 1 cm H2O b. +1 cm H2O c. 0 cm H2O d. 5 cm H2O
.
ANS: A
During normal spontaneous ventilation alveolar pressure will become 1 cm H2O which is the lowest. During the exhalation of a normal spontaneous breath the alveolar pressure will become +1 cm H2O. 5. The pressure required to maintain alveolar inflation is known as which of the following? a. Transairway pressure (PTA) b. Transthoracic pressure (PTT) c. Transrespiratory pressure (PTR) d. Transpulmonary pressure (PL) ANS: D
The definition of transpulmonary pressure (PL) is the pressure required to maintain alveolar inflation. Transairway pressure (PTA) is the pressure gradient required to produce airflow in the conducting tubes. Transrespiratory pressure (PTR) is the pressure to inflate the lungs and airways during positive-pressure ventilation. Transthoracic pressure (PTT) represents the pressure required to expand or contract the lungs and the chest wall at the same time. 6. Calculate the pressure needed to overcome airway resistance during positive-pressure
ventilation when the proximal airway pressure (Pawo) is 35 cm H2O and the alveolar pressure (PA) is 5 cm H2O. a. 7 cm H2O b. 30 cm H2O c. 40 cm H2O d. 175 cm H2O
ANS: B
The transairway pressure (PTA) is used to calculate the pressure required to overcome airway resistance during mechanical ventilation. This formula is PTA = Pawo PA. 7. The term used to describe the tendency of a structure to return to its original form after being
stretched or acted on by an outside force is which of the following? Elastance Compliance Viscous resistance Distending pressure
a. b. c. d.
ANS: A
The elastance of a structure is the tendency of that structure to return to its original shape after being stretched. The more elastance a structure has, the more difficult it is to stretch. The compliance of a structure is the ease with which the structure distends or stretches. Compliance is the opposite of elastance. Viscous resistance is the opposition to movement offered by adjacent structures such as the lungs and their adjacent organs. Distending pressure is pressure required to maintain inflation, for example, alveolar distending pressure. 8. Calculate the pressure required to achieve a tidal volume of 400 mL for an intubated patient
with a respiratory system compliance of 15 mL/cm H2O. 6 cm H2O 26.7 cm H2O 37.5 cm H2O 41.5 cm H2O
a. b. c. d.
ANS: B
C = V/P then P = V/C 9. Which of the following conditions causes pulmonary compliance to increase? a. Asthma b. Kyphoscoliosis c. Emphysema d. Acute respiratory distress syndrome (ARDS) ANS: C
Emphysema causes an increase in pulmonary compliance, whereas ARDS and kyphoscoliosis cause decreases in pulmonary compliance. Asthma attacks cause increase in airway resistance. 10. Calculate the effective static compliance (Cs) given the following information about a patient
receiving mechanical ventilation: peak inspiratory pressure (PIP) is 56 cm H2O, plateau pressure (Pplat) is 40 cm H2O, exhaled tidal volume (VT) is 650 mL, and positive endexpiratory pressure (PEEP) is 10 cm H2O. a. 14.1 mL/cm H2O b. 16.3 mL/cm H2O c. 21.7 mL/cm H2O d. 40.6 mL/cm H2O ANS: C
The formula for calculating effective static compliance is Cs = VT/(Pplat
EEP).
11. Based upon the following patient information, calculate the patient’s static lung compliance:
exhaled tidal volume (VT) is 675 mL, peak inspiratory pressure (PIP) is 28 cm H2O, plateau pressure (Pplat) is 8 cm H2O, and PEEP is set at 5 cm H2O. a. 0.02 L/cm H2O b. 0.03 L/cm H2O c. 0.22 L/cm H2O d. 0.34 L/cm H2O ANS: C
The formula for calculating effective static compliance is Cs = VT/(Pplat
EEP).
12. A patient receiving mechanical ventilation has an exhaled tidal volume (VT) of 500 mL and a
positive end-expiratory pressure setting (PEEP) of 5 cm H2O. Patient-ventilator system checks reveal the following data: Time PIP (cm H2O) Pplat (cm H2O) 0600 27 15 0800 29 15 1000 36 13 The respiratory therapist should recommend which of the following for this patient? 1. Tracheobronchial suctioning 2. Increase in the set tidal volume 3. adrenergic bronchodilator therapy 4. Increase positive end-expiratory pressure a. 1 and 3 only b. 2 and 4 only c. 1, 2, and 3 only d. 2, 3, and 4 only ANS: A
Calculate the transairway pressure (PTA) by subtracting the plateau pressure from the peak inspiratory pressure. Analyzing the PTA will show any changes in the pressure needed to overcome airway resistance. Analyzing the Pplateau will demonstrate any changes in compliance. The Pplateau remained the same for the first two checks and then actually dropped at the 1000-hour check. Analyzing the PTA, however, shows a slight increase between 0600 and 0800 (from 12 to 14 cm H2O) and then a sharp increase to 23 cm H2O at 1000. Increases in PTA signify increases in airway resistance. Airway resistance may be caused by secretion buildup, bronchospasm, mucosal edema, and mucosal inflammation. Tracheobronchial suctioning will remove any secretion buildup, and a adrenergic bronchodilator will reverse bronchospasm. Increasing the tidal volume will add to the airway resistance according to Poiseuille’s law. Increasing the PEEP will not address the root of this patient’s problem; the patient’s compliance is normal. 13. The values below pertain to a patient who is being mechanically ventilated with a measured
exhaled tidal volume (VT) of 700 mL. Time Peak Inspiratory Plateau Pressure (cm Pressure (cm H2O) H2O) 0800 35 30 1000 39 34 1100 45 39
1130 50 44 Analysis of this data points to which of the following conclusions? a. Airway resistance is increasing. b. Airway resistance is decreasing. c. Lung compliance is increasing. d. Lung compliance is decreasing. ANS: D
To evaluate this information the transairway pressure (PTA) is calculated for the different times: 0800 PTA = 5 cm H2O, 1000 PTA = 5 cm H2O, 1100 PTA = 6 cm H2O, and 1130 PTA = 6 cm H2O. This data shows that there is no significant increase or decrease in this patient’s airway resistance. Analysis of the patient’s plateau pressure (Pplat) reveals an increase of 15 cm H2O over the three and a half hour time period. This is directly related to a decrease in lung compliance. Calculation of the lung compliance reveals a steady decrease from 20 mL/cm H2O to 14 mL/cm H2O.
at each time interval
14. The respiratory therapist should expect which of the following findings while ventilating a
patient with acute respiratory distress syndrome (ARDS)? An elevated plateau pressure (Pplat) A decreased elastic resistance A low peak inspiratory pressure (PIP) A large transairway pressure (PTA) gradient
a. b. c. d.
ANS: A
ARDS is a pathological condition that is associated with a reduction in lung compliance. The formula for static compliance (CS) utilizes the measured plateau pressure (Pplat) in its denominator (CS = VT/[Pplat – EEP]). Therefore, with a consistent exhaled tidal volume (VT), an elevated Pplat will decrease CS. 15. The formula used for the calculation of static compliance (CS) is which of the following? a. (Peak inspiratory pressure [PIP] EEP)/tidal volume (VT) b. (Plateau pressure [Pplat] EEP)/tidal volume (VT) c. Tidal volume/(plateau pressure EEP) d. Tidal volume/(peak pressure [PIP] plateau pressure [Pplat]) ANS: C
16. Plateau pressure (Pplat) is measured during which phase of the ventilatory cycle? a. Inspiration b. End-inspiration c. Expiration d. End-expiration ANS: B
The calculation of compliance requires the measurement of the plateau pressure. This pressure measurement is made during no-flow conditions. The airway pressure (Pawo) is measured at end-inspiration. The inspiratory pressure is taken when the pressure reaches its maximum during a delivered mechanical breath. The pressure that occurs during expiration is a dynamic measurement and drops during expiration. The pressure reading at end-expiration is the baseline pressure; this reading is either at zero (atmospheric pressure) or at above atmospheric pressure (PEEP). 17. The condition that is associated with an increase in airway resistance is which of the
following? Pulmonary edema Bronchospasm Fibrosis Ascites
a. b. c. d.
ANS: B
Airway resistance is determined by the gas viscosity, gas density, tubing length, airway diameter, and the flow rate of the gas through the tubing. The two factors that are most often subject to change are the airway diameter and the flow rate of the gas. The flow rate of the gas during mechanical ventilation is controlled. Pulmonary edema is fluid accumulating in the alveoli and will cause a drop in the patient’s lung compliance. Bronchospasm causes a narrowing of the airways and will, therefore, increase the airway resistance. Fibrosis causes an inability of the lungs to stretch, decreasing the patient’s lung compliance. Ascites causes fluid buildup in the peritoneal cavity and increases tissue resistance, not airway resistance. 18. An increase in peak inspiratory pressure (PIP) without an increase in plateau pressure (Pplat) is
associated with which of the following? Increase in static compliance (CS) Decrease in static compliance (CS) Increase in airway resistance Decrease in airway resistance
a. b. c. d.
ANS: C
The PIP represents the amount of pressure needed to overcome both elastance and airway resistance. The Pplat is the amount of pressure required to overcome elastance alone. Since the Pplat has remained constant in this situation, the static compliance is unchanged. The difference between the PIP and the Pplat is the transairway pressure (PTA) and represents the pressure required to overcome the airway resistance. If PTA increases, the airway resistance is also increasing, when the gas flow rate remains the same. 19. The patient-ventilator data over the past few hours demonstrates an increased peak inspiratory
pressure (PIP) with a constant transairway pressure (PTA). The respiratory therapist should conclude which of the following? a. Static compliance (CS) has increased. b. Static compliance (CS) has decreased. c. Airway resistance (Raw) has increased. d. Airway resistance (Raw) has decreased. ANS: B
The PIP represents the amount of pressure needed to overcome both elastance and airway resistance. The Pplat is the amount of pressure required to overcome elastance alone, and is the pressure used to calculate the static compliance. Since PTA has stayed the same, it can be concluded that Raw has remained the same. Therefore, the reason the PIP has increased is because of an increase in the Pplat. This correlates to a decrease in CS. 20. Calculate airway resistance (Raw) for a ventilator patient, in cm H2O/(L/s), when the peak
inspiratory pressure (PIP) is 50 cm H2O, the plateau pressure (Pplat) is 15 cm H2O, and the set flow rate is 60 L/min. a. 0.58 Raw b. 1.2 Raw c. 35 Raw d. 50 Raw ANS: C
21. Calculate airway resistance (Raw) for a ventilator patient, in cm H2O/(L/s), with the following
information: Peak inspiratory pressure (PIP) is 20 cm H2O, plateau pressure (Pplat) is 15 cm H2O, PEEP is 5 cm H2O, and set flow rate is 50 L/min. a. 5 Raw b. 6 Raw c. 10 Raw d. 15 Raw ANS: B
and flow is in L/s. 22. Calculate the static compliance (CS), in mL/cm H2O, when PIP is 47 cm H2O, plateau pressure
(Pplat) is 27 cm H2O, baseline pressure is 10 cm H2O, and exhaled tidal volume (VT) is 725 mL. a. 43 CS b. 36 CS c. 20 CS d. 0.065 CS ANS: A
CS = VT/(Pplat
EEP)
23. Calculate the inspiratory time necessary to ensure 98% of the volume is delivered to a patient
with a Cs = 40 mL/cm H2O and the Raw = 1 cm H2O/(L/s). a. 0.04 s b. 0.16 s c. 1.6 s d. 4.0 s ANS: B
. 98% of the volume will be delivered in 4 time constants. Therefore, multiply 4 times the time constant.
24. How many time constants are necessary for 95% of the tidal volume (VT) to be delivered from
a mechanical ventilator? 1 2 3 4
a. b. c. d.
ANS: C
One time constant allows 63% of the volume to be inhaled; 2 time constants allow about 86% of the volume to be inhaled; 3 time constants allow about 95% to be inhaled; 4 time constants allow about 98% to be inhaled; and 5 time constants allow 100% to be inhaled. 25. Compute the inspiratory time necessary to ensure 100% of the volume is delivered to an
intubated patient with a Cs = 60 mL/cm H2O and the Raw = 6 cm H2O/(L/s). 0.36 s 0.5 s 1.4 s 1.8 s
a. b. c. d.
ANS: D
Time constant (TC) = C (L/cm H2O) R (cm H2O/[L/s]). 100% of the volume will be delivered in 5 time constants. Therefore, multiply 5 times the time constant. 26. Evaluate the combinations of compliance and resistance and select the combination that will
cause the lungs to fill fastest. a. b. c. d. ANS: C
Use the time constant formula, TC = C R, to determine the time constant for each choice. The time constant for answer A is 0.1 s. The time constant for answer B is 1 s. The time constant for answer C is 0.03 s, and the time constant for answer D is 0.3 s. The product of multiplying the time constant by 5 is the inspiratory time needed to deliver 100% of the volume. 27. The statement that describes the alveolus shown in Figure 1-1 is which of the following?
1. Requires more time to fill than a normal alveolus 2. Fills more quickly than a normal alveolus
3. Requires more volume to fill than a normal alveolus 4. More pressure is needed to achieve a normal volume a. 1 and 3 only b. 2 and 4 only c. 2 and 3 only d. 1, 3, and 4 only ANS: B
The figure shows a low-compliant unit, which has a short time constant. This means it takes less time to fill and empty and will require more pressure to achieve a normal volume. Lung units that require more time to fill are high-resistance units. Lung units that require more volume to fill than normal are high-compliance units. 28. Calculate the static compliance (CS), in mL/cm H2O, when PIP is 26 cm H2O, plateau pressure
(Pplat) is 19 cm H2O, baseline pressure is 5 cm H2O, and exhaled tidal volume (VT) is 425 mL. 16 20 22 30
a. b. c. d.
ANS: D
29. What type of ventilator increases transpulmonary pressure (PL) by mimicking the normal
mechanism for inspiration? a. Positive-pressure ventilation (PPV) b. Negative-pressure ventilation (NPV) c. High-frequency oscillatory ventilation (HFOV) d. High-frequency positive-pressure ventilation (HFPPV) ANS: D
Negative-pressure ventilation (NPV) attempts to mimic the function of the respiratory muscles to allow breathing through normal physiological mechanisms. Positive-pressure ventilation (PPV) pushes air into the lungs by increasing the alveolar pressure. High-frequency oscillatory ventilation (HFOV) delivers very small volumes at very high rates in a “to-andfro” motion by pushing the gas in and pulling it out during exhalation. High-frequency positive-pressure ventilation (HFPPV) pushes in small volumes at high respiratory rates. 30. Air accidentally trapped in the lungs due to mechanical ventilation is known as which of the
following? Plateau pressure (Pplat) Functional residual capacity (FRC) Extrinsic positive end-expiratory pressure (extrinsic PEEP) Intrinsic positive end-expiratory pressure (intrinsic PEEP)
a. b. c. d.
ANS: D
The definition of intrinsic PEEP is air that is accidentally trapped in the lung. Another name for this is auto-PEEP. Extrinsic PEEP is the positive baseline pressure that is set by the operator. Functional residual capacity (FRC) is the sum of a patient’s residual volume and expiratory reserve volume and is the amount of gas that normally remains in the lung after a quiet exhalation. The plateau pressure is the pressure measured in the lungs at no flow during an inspiratory hold maneuver. 31. The transairway pressure (PTA) shown in this figure is which of the following?
a. b. c. d.
5 cm H2O 10 cm H2O 20 cm H2O 30 cm H2O
ANS: B
, where the PIP is 30 cm H2O and the Pplat is 20 cm H2O. The PEEP is 5 cm H2O. 32. Use this figure to compute the static compliance (CS) for an intubated patient with an exhaled
tidal volume (VT) of 500 mL.
a. b. c. d.
14 mL/cm H2O 20 mL/cm H2O 33 mL/cm H2O 50 mL/cm H2O
ANS: D
; the Pplat in the figure is 20 cm H2O and the PEEP is 10 cm H2O.
33. Evaluate the combinations of compliance and resistance and select the combination that will
cause the lungs to empty slowest. a. b. c. d. ANS: B
Use the time constant formula, TC = C R, to determine the time constant for each choice. The combination with the longest time constant will empty the slowest. The time constant for A is 0.1 s, B is 0.3 s, C is 0.15 s, and D is 0.24 s. To find out how many seconds for emptying, multiply the time constant by 5. 34. Use this figure to compute the static compliance for an intubated patient with an inspiratory
flow rate set at 70 L/min.
a. 0.2 cm H2O/(L/s) b. 11.7 cm H2O/(L/s) c. 16.7 cm H2O/(L/s) d. 20 cm H2O/(L/s) ANS: B
Use the graph to determine the PIP (34 cm H2O) and the Pplat (20 cm H2O). Convert the flow into L/s (70 L/min/60 = 1.2 L/s). Then, Raw = (PIP – Pplat)/flow. 35. The ventilator that functions most physiologically uses which of the following? a. Open loop b. Double circuit c. Positive pressure d. Negative pressure ANS: D
Air is caused to flow into the lungs with a negative pressure ventilator because the ventilator generates a negative pressure at the body surface that is transmitted to the pleural space and then to the alveoli. The transpulmonary pressure becomes greater because the pleural pressure drops. This closely resembles how a normal spontaneous breath occurs. 36. 1 mm Hg = a. 7.5 mm H2O b. 1.30 atm c. 1.36 cm H2O
d. 1034 cm H2O ANS: C
1 mm Hg = 1.36 cm H2O 1 kPa = 7.5 mm Hg 1 Torr = 1 mm Hg 1 atm = 760 mm Hg = 1034 cm H2O 37. Which of the following statements best defines elastance? a. Ability of a structure to stretch b. Ability of a structure to return to its natural shape after stretching c. Ability of a structure to stretch and remain in that position d. Ability of a structure to fill and empty during static conditions ANS: B
The opposite of compliance, elastance is the tendency of a structure to return to its original form after being stretched or acted on by an outside force. 38. The term used to describe the opposition to movement offered by adjacent structures such as
the lungs and their adjacent organs is which of the following? Elastance Compliance Viscous resistance Distending pressure
a. b. c. d.
ANS: C
The elastance of a structure is the tendency of that structure to return to its original shape after being stretched. The more elastance a structure has, the more difficult it is to stretch. The compliance of a structure is the ease with which the structure distends or stretches. Compliance is the opposite of elastance. Viscous resistance is the opposition to movement offered by adjacent structures such as the lungs and their adjacent organs. Distending pressure is pressure required to maintain inflation, for example, alveolar distending pressure. 39. Using a sensor, where do current ICU mechanical ventilators measure airway pressure (PAW)? a. At the patient’s airway opening b. By placing a specially designed balloon in the esophagus c. Proximal to the expiratory valve d. Airway pressure cannot be measured ANS: C
During mechanical ventilation, proximal airway pressure is not typically measured at the airway opening due to accumulation of secretions and technical errors can alter sensor measurements. Current generation ICU mechanical ventilators measure airway pressure (Paw) using a sensor positioned proximal to the expiratory valve, which is closed during the inspiration. The ventilator manometer pressure displayed on the user interface of the ventilator is typically designated as airway pressure (Paw). Intrapleural pressure (Ppl) is the pressure in the potential space between the parietal and visceral pleurae. Ppl is normally about –5 cm H2O at the end of expiration during spontaneous breathing. It is about –10 cm H2O at the end of inspiration. Because Ppl is often difficult to measure in a patient, a related measurement is used, the esophageal pressure (Pes), which is obtained by placing a specially designed balloon in the esophagus; changes in the balloon pressure are used to estimate pressure and pressure changes in the pleural space.
Chapter 02: How Ventilators Work Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The respiratory therapist enters modes and parameters into the ventilator with which of the
following? Control logic Input power User interface Drive mechanism
a. b. c. d.
ANS: C
The user interface or control panel contains certain dials or a touch panel where the ventilator operator sets or enters certain information to establish how the pressure and pattern of gas flow are delivered by the machine. Inside the ventilator is the control logic or control system that interprets the operator settings and produces and regulates the desired output. The input power is the ventilator’s power source that provides the energy to enable the ventilator to perform the work of ventilating the patient. The drive mechanism is a mechanical device that produces gas flow to the patient. 2. A patient being transferred from a hospital to a skilled nursing facility requires mechanical
ventilation with a fractional inspired oxygen (FIO2) of 0.21. The skilled nursing facility has no piped in gases. Which of the following ventilators will be able to function in the skilled nursing facility without any extra equipment? a. Servoi b. LTV 1000 c. Bird Mark 7 d. PB 980 ANS: B
The type of ventilator that will be appropriate for this situation is one that is electrically controlled and powered with a built-in air compressor. The LTV 1000 fits this description. The Servoi and the PB980 require both a high-pressure gas source and electrical power. The Bird Mark 7 is a pneumatic ventilator and will not be able to function in this situation. 3. The internal circuit of a ventilator allows the gas to go directly from its power source into the
patient. This is known as which of the following? Single-circuit Open loop Closed loop Double-circuit
a. b. c. d.
ANS: A
There are two types of internal circuits, the single- and the double-circuit. The single-circuit allows the gas to flow from its power input source to the patient. The double-circuit utilizes a primary power source to generate a gas flow that compresses a mechanism such as a bellows. The gas within the bellows will then flow to the patient. Open loop and closed loop refer to the absence and presence, respectively, of a feedback loop system.
4. A ventilator for which the primary power source generates a gas flow that compresses another
mechanism and causes the gas from inside the mechanism to be delivered to the patient is known as which of the following? a. Single-circuit b. Double-circuit c. Closed loop d. Open loop ANS: B
In a double-circuit ventilator, the primary power source generates a gas flow that compresses a mechanism such as a bellows or “bag-in-a-chamber.” The gas in the bellows or bag then flows to the patient. In a single-circuit ventilator, the primary power source travels directly to the patient. The closed and open loops refer to whether or not the ventilator has a feedback loop system. 5. The function of the exhalation valve is to do which of the following? a. Adjust the flow going to the patient. b. Close during exhalation to vent patient gas. c. Seal the external circuit during inspiration. d. Determine the volume being delivered. ANS: C
During inspiration, gas fills the balloon and closes a hole in the expiratory valve. Closing of the hole makes the patient circuit a sealed system. During expiration, the balloon deflates, the hole opens, and gas from the patient is exhaled into the room through the hole. 6. In the image, what does “B” represent?
a. b. c. d.
Expiratory valve line Exhalation valve Expiratory line Main inspiratory line
ANS: C
The external exhalation valve is represented by the letter “C” in the figure. “B” is pointing to the expiratory line. The main inspiratory line is represented by the letter “A.” The expiratory valve line is represented by “D.” 7. The type of compressor that is used by hospitals to supply wall compressed air has which of
the following? a. Piston b. Bellows
c. Rotating blades d. Moving diaphragm ANS: A
Hospitals use large, piston-type, water-cooled compressors to supply wall gas outlets. 8. The power transmission and conversion system of a ventilator is defined as which of the
following? a. A mechanical device that produces gas flow to the patient b. An electrical motor that is connected by a special gearing mechanism c. The system that interprets the settings and produces or regulates the desired output d. Internal hardware that changes electrical or pneumatic energy into mechanical energy ANS: D
The power transmission and conversion system changes the energy from the power source into mechanical energy. The linear drive piston is a mechanical device that produces gas flow to the patient. The drive mechanism is an electrical motor that is connected by a special gearing mechanism. It is the control system that interprets the operator settings and produces or regulates the desired output. 9. The volume-displacement device that creates a sinusoidal flow waveform is which of the
following? Rotary drive piston Linear drive piston Spring-loaded bellows Proportional solenoid
a. b. c. d.
ANS: A
The rotary drive piston creates a flow pattern that is slow at the beginning of inspiration, achieves highest speed at mid-inspiration, and tapers off at end-inspiration, creating a sinusoidal waveform (sine waveform). 10. Modern intensive care units’ (ICU) ventilators regulate gas flow to the patient by using which
of the following? Rotary drive pistons Linear drive pistons Proportional solenoids Spring-loaded bellows
a. b. c. d.
ANS: C
Proportional solenoid valves control flow by opening and closing either completely or in small increments. These valves, which are driven by various motor-based mechanisms, have a rapid response time and great flexibility in flow control. The other answers are all volumedisplacement devices. 11. A series of tubes that allow gas to flow inside the ventilator and between the ventilator and the
patient is referred to as the a. pneumatic circuit. b. control circuit. c. control scheme.
d. patient circuit. ANS: A
A pneumatic circuit, or pathway, is a series of tubes that allow gas to flow inside the ventilator and between the ventilator and the patient. 12. In a spring-loaded bellows volume-delivery device, the amount of pressure is determined by
the a. b. c. d.
location of the bellows. volume setting on the ventilator. tightness of the spring. electrical power provided to the spring.
ANS: C
In a spring-loaded bellows model, an adjustable spring atop a bellows applies a force per unit area, or pressure (P = force/area). Tightening of the spring creates greater force and therefore greater pressure. The bellows contains pre-blended gas (air and oxygen), which is administered to the patient. 13. Which of the following is an example of a flow control valve? a. Linear piston b. Spring-loaded bellows c. Solenoid d. Rotary drive piston ANS: C
Flow-control valves include proportional solenoid valves and digital valves with on/off configurations.
Chapter 03: How a Breath Is Delivered Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The equation of motion describes the relationships between which of the following? a. Pressure and flow during a mechanical breath b. Pressure and volume during a spontaneous breath c. Flow and volume during a mechanical or spontaneous breath d. Flow, volume, and pressure during a spontaneous or mechanical breath ANS: D
The mathematical model that relates pressure, volume, and flow during ventilation is known as the equation of motion for the respiratory system. This means muscle . 2. The equation of motion is represented by which of the following? a. b. c. d. ANS: B
The transrespiratory pressure (PTR) is the pressure generated by either the patient contracting the respiratory muscles or by the ventilator pushing the volume into the patient. This pressure is opposed by the elastic recoil pressure (PE) and the flow resistance pressure (PR). The transairway pressure (PTA) is the pressure gradient between the airway opening and the alveolus. This produces airway movement in the conductive airways. It represents only part of the equation of motion, the pressure needed to overcome the airway resistance. The equation of motion may be represented, on one side, by Pvent + muscle pressure (Pmus). However, this is equal to the elastic recoil pressure (V/C) plus the flow resistance pressure . 3. How many variables can a ventilator control at one time? a. One b. Two c. Three d. Four ANS: A
As the equation of motion shows, the ventilator can control four variables: pressure, volume, flow, and time. It is important to recognize that the ventilator can control only one variable at a time. 4. Calculate the transrespiratory pressure given the following information: volume 0.6 L;
compliance 1 L/cm H2O; airway resistance 3 cm H2O/(L/s); flow 1 L/s. a. 0.9 cm H2O b. 1.8 cm H2O
c. 3.6 cm H2O d. 4.6 cm H2O ANS: C
Transrespiratory pressure
.
5. An increase in airway resistance during volume-controlled ventilation will have which of the
following effects? Volume increase Flow decrease Pressure increase Rate decrease
a. b. c. d.
ANS: C
When a ventilator is volume-controlled the ventilator will maintain the volume, which will remain unchanged, along with the flow, but the pressure will vary with changes in lung characteristics. An increase in airway pressure will require more pressure to deliver the set volume. The set rate is independent of the changes in pressure. 6. An increase in airway resistance during pressure-targeted ventilation will have which of the
following effects? a. Volume decrease b. Flow increase c. Pressure increase d. Rate decrease ANS: A
During pressure-targeted (pressure-controlled) ventilation, pressure is unaffected by changes in lung characteristics. However, an increase in airway resistance will cause less volume to be delivered and will change the flow waveform. The set pressure will not be able to overcome the increased resistance, resulting in less volume delivery and a decrease in flow (V/TI). 7. A patient who has a decrease in lung compliance due to acute respiratory distress syndrome
during volume-limited ventilation will cause which of the following? Increased volume delivery Increased peak pressure Decreased flow delivery Decreased peak pressure
a. b. c. d.
ANS: B
When a patient is being ventilated in a volume-limited mode the ventilator will maintain the volume, which will remain unchanged, along with the flow, but the pressure will vary with changes in lung characteristics. A decrease in lung compliance will cause the amount of pressure needed to overcome elastance to increase. This will increase the peak pressure needed to deliver the set volume. Flow and volume will remain constant. 8. During pressure-targeted ventilation the patient’s airway resistance decreases to normal due to
medication delivery. The ventilator will respond with which of the following changes? 1. Altered flow waveform 2. Increased pressure 3. Increased volume
4. Decrease volume 1 and 3 only 2 and 4 only 1 and 4 only 1, 2, and 3 only
a. b. c. d.
ANS: A
During pressure-targeted ventilation the pressure remains constant and the flow and volume will respond to changes in the patient lung and airway characteristics. An improvement in airway resistance will make it easier to put more volume into the lungs with the same pressure setting as compared to volume delivery with increased airway resistance. Since volume and flow waveform will vary with changes in airway resistance, the volume will increase and the flow waveform will change with improvements in airway resistance. In pressure-targeted ventilation the pressure does not change. A decreased volume would be the result of worsening airway resistance. 9. High-frequency oscillators control which of the following variables? a. Flow b. Time c. Volume d. Pressure ANS: B
High-frequency oscillators control both inspiratory and expiratory time. 10. The ventilator variable that begins inspiration is which of the following? a. Cycle b. Limit c. Trigger d. Baseline ANS: C
The trigger mechanism ends the expiratory phase and begins the inspiratory phase. Limit is the maximum value that a variable may reach during inspiration. Cycle terminates the inspiratory phase. The baseline variable is applied during exhalation and is the pressure level from which a ventilator breath begins. 11. The trigger variable in the controlled mode is which of the following? a. Flow b. Time c. Pressure d. Volume ANS: B
In the controlled mode the ventilator initiates all the breathing because the patient cannot. All ventilator-initiated breaths are time triggered. Flow, pressure, and volume triggers are patient initiated. 12. A patient who has been sedated and paralyzed by medications is being controlled by the
ventilator. The set rate is 15 breaths/min. How many seconds does it take for inspiration and expiration to occur?
a. b. c. d.
2s 4s 6s 8s
ANS: B
60 s/min divided by 15 breaths/min = 4 s 13. The most commonly used patient-trigger variables include which of the following?
1. Flow 2. Time 3. Pressure 4. Volume a. 1 and 3 only b. 2 and 4 only c. 1 and 4 only d. 2 and 3 only ANS: A
The patient trigger variables are flow, pressure, and volume. Time is the ventilator trigger variable. The most common of the three patient triggers are flow and pressure. Very few ventilators use volume as a patient trigger. 14. A patient is receiving volume-controlled ventilation. The respiratory therapist notes the
pressure–time scalar on the ventilator screen, shown in the figure. The most appropriate action to take includes which of the following?
a. b. c. d.
Increase the rate setting. Increase the baseline setting. Decrease the volume setting. Increase the sensitivity setting.
ANS: D
What is being shown in the figure is a trigger pressure of 5 cm H2O below the baseline setting of 5 cm H2O. This is seen during the pressure trigger dropping down to 0 cm H2O during the trigger. In this situation the machine is not sensitive enough to the patient’s effort. The patient is working too hard to trigger the ventilator breath. The respiratory therapist needs to increase the ventilator sensitivity control. Changing any of the other parameters will not decrease the work that the patient is doing to trigger inspiration.
15. The inspiratory and expiratory flow sensors are reading a base flow of 5 L/min. The flow
trigger is set to 2 L/min. The expiratory flow sensor must read what flow to trigger inspiration? a. 1 L/min b. 2 L/min c. 3 L/min d. 4 L/min ANS: C
Base flow minus flow trigger setting is equal to the flow needed to be sensed at the expiratory flow sensor to trigger inspiration. 16. The patient trigger that requires the least amount of work of breathing for the patient is which
of the following? Time Flow Pressure Volume
a. b. c. d.
ANS: B
When set properly, flow triggering has been shown to require less work of breathing than pressure triggering. 17. The limit variable set on a mechanical ventilator will do which of the following? a. End-inspiration b. Begin inspiration c. Control the maximum value allowed d. Control the minimum value allowed ANS: C
A limit variable is the maximum value a variable can attain. It limits the variable during inspiration but does not end the inspiratory phase. The cycle setting ends inspiration. The trigger variable begins inspiration, and there is no control over the minimum value. 18. The control variables most often used to ventilate infants are which of the following? a. Volume limited, time cycled ventilation b. Pressure limited, time cycled ventilation c. Pressure limited, pressure cycled ventilation d. Volume limited, volume cycled ventilation ANS: B
Infant ventilators most often limit the pressure delivered and end-inspiration using inspiratory time. Volume limited, volume cycled ventilation is volume-controlled ventilation. Pressure limited, pressure cycled ventilation is the type of breath used during intermittent positive pressure breathing (IPPB). 19. The respiratory therapist enters the room of a patient being mechanically ventilated with
volume ventilation. The high-pressure alarm is sounding and the measured exhaled tidal volume is significantly lower than what is set. The variable that is ending inspiration is which of the following? a. Time
b. Flow c. Pressure d. Volume ANS: C
Volume ventilation is cycled by volume. However, to protect the patient’s lungs from high pressures a maximum high-pressure limit is set (usually 10 cm H2O above the average peak inspiratory pressure). Inspiration ends prematurely when the high-pressure limit is reached, independent of the set volume. This is the reason why the exhaled tidal volume reading is significantly lower than the set volume. Therefore, the variable ending inspiration in this instance is pressure. 20. The variable that a ventilator uses to end-inspiration is known as which of the following? a. Cycle b. Limit c. Trigger d. Baseline ANS: B
Cycle is the term used to call the variable that is used to end-inspiration. Limit is the maximum setting for a variable. Trigger is the term used to call the variable that is used to begin inspiration. Baseline is the pressure at the end of inspiration. 21. When the maximum pressure limit is reached during volume ventilation, which of the
following occurs? 1. Inspiratory time is decreased. 2. Volume delivered is decreased. 3. Inspiration continues until volume is delivered. 4. Pressure is held and the breath is volume cycled. a. 3 only b. 4 only c. 1 and 2 only d. 2 and 4 only ANS: C
The maximum pressure limit is a safety mechanism used during volume ventilation to avoid excessive pressure in the lungs. When the pressure measured by the ventilator reaches the maximum pressure limit inspiration ends. This means that the inspiratory time will be decreased and the volume delivered will be less than the set volume. Therefore, reaching maximum pressure limit causes the delivered breath to be pressure cycled. 22. The respiratory therapist is called to a patient’s room because the “alarms are ringing.” When
the respiratory therapist arrives at the bedside, the high-pressure limit, low exhaled tidal volume, and low exhaled minute volume alarms are active. The cause of these alarms is which of the following? a. Disconnection from the ventilator b. Critical leak in the ventilator circuit c. Lung compliance has improved d. Airway resistance has increased ANS: D
The low exhaled tidal volume and minute volume alarms are active when the high-pressure limit alarm is active. This occurs because reaching the set high-pressure limit setting will endinspiration immediately by pressure cycling and thereby will decrease the volume delivered to the patient. When the high-pressure limit alarm is active for several breaths, the low exhaled tidal volume and then the minute ventilation alarms will become active. The high-pressure alarm will sound when airway resistance is elevated (e.g., asthma). A disconnect from the ventilator or a critical leak would cause the low peak inspiratory pressure alarms to ring. Improved lung compliance will lower the peak inspiratory pressure and may trigger a low pressure alarm. 23. The most common method of terminating inspiration during pressure support ventilation is
which of the following? Flow Time Pressure Volume
a. b. c. d.
ANS: A
During pressure support ventilation, when a breath is delivered, the flow will begin to taper down after a very short period of time. When flow drops to a certain percentage of the initial peak flow the ventilator flow cycles out of inspiration. A time cycled breath is usually a breath that is controlled by the ventilator during pressure control ventilation. Pressure cycling is used for intermittent positive pressure breathing (Bird Mark 7). Volume cycling is utilized during ventilator breaths on certain ventilators. 24. What is the flow-cycle setting for the following pressure supported breath?
a. b. c. d.
20% 30% 40% 50%
ANS: D
The peak flow for this pressure supported breath is 40 L/min. The breath flow cycled at 20 L/min, which is 50% of the peak flow. Therefore, the flow-cycle setting is 50%. 25. Which maneuver will maintain air in the lungs at the end of inspiration, before the exhalation
valve opens? a. Pressure limit b. Inspiratory hold c. Expiratory hold
d. Expiratory resistance ANS: B
The inspiratory hold, inspiratory pause, or end-inspiratory pause is the maneuver that will maintain air in the lungs and extend inspiration. Pressure limit allows pressure to rise but not exceed a pressure limit setting. Expiratory hold is the maneuver that will obtain the unintended positive end-expiratory pressure (auto-PEEP) measurement. The ventilator pauses before delivering the next machine breath. Expiratory resistance is a resistance added to exhalation to mimic pursed-lip breathing. 26. The pressure–time scalar shown in the figure could be caused by which of the following?
a. b. c. d.
Inspiratory hold Clogged expiratory filter Excessive secretions in the airway Negative end-expiratory pressure
ANS: B
What is being shown in the figure is a peak pressure of 20 cm H2O and then a very slow drop in the pressure over the course of approximately 1 s. Normally, as soon as the peak inspiratory pressure is reached, the pressure drops rapidly and remains at baseline until the next breath is given. A clogged expiratory filter will increase the resistance in the filter. This will cause there to be difficulty exhaling through this filter, showing up as a slow drop in pressure during the exhalation period. An inspiratory hold would cause there to be a plateau in the pressure–time scalar. Excessive secretions in the airway would elevate the peak inspiratory pressure to a point where the maximum safety pressure may be reached. The presence of negative endexpiratory pressure (NEEP) would pull the pressure down rapidly from the peak and drop it slightly below the baseline during that time. 27. A ventilator is set to deliver a 600 mL tidal volume. The flow rate is set at 40 L/min and the
frequency is set at 10 breaths/min. If the flow rate is doubled and the patient is not assisting, which of the following will occur? a. The frequency will decrease. b. The tidal volume will increase. c. The expiratory time will increase. d. The inspiratory time will increase. ANS: C
If you manipulate the formula: flow = volume change/time to volume/flow = time, and use the numbers from this example, it can be shown that by increasing the flow rate the inspiratory time will decrease. Since the frequency remains constant, then the inspiratory time will decrease, thereby increasing expiratory time. 28. The variable that controls exhalation is known as which of the following? a. Limit b. Trigger c. Pressure d. Baseline ANS: D
The baseline variable is the parameter that generally is controlled during exhalation. Although either volume or flow could serve as a baseline variable, pressure is the most practical choice and is used by all modern ventilators. 29. In pressure targeted ventilation the trigger variable for a patient who is sedated is which of the
following? Time Flow Volume Pressure
a. b. c. d.
ANS: A
When the patient is not triggering a breath, as with sedation, the set mechanical ventilator rate will be time-triggered based on the backup set rate.
Chapter 04: Establishing the Need for Mechanical Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Respiratory failure due to inadequate ventilation is known as which of the following? a. Hypoxemic b. Hypercapnic c. Compensated d. Chronic ANS: B
Inadequate ventilation decreases the amount of carbon dioxide excreted by the lungs. This causes a buildup of carbon dioxide in the blood, which is hypercapnia. 2. The underlying physiological process leading to pure hypercapnic respiratory failure is which
of the following? a. Ventilation/perfusion mismatch b. Intrapulmonary shunting c. Diffusion impairment d. Alveolar hypoventilation ANS: D
When a person cannot achieve adequate ventilation to maintain a normal partial pressure of carbon dioxide in the arteries (PaCO2), it is known as acute hypercapnic respiratory failure. Ventilation/perfusion (V/Q) mismatch, intrapulmonary shunting, and diffusion impairment lead to hypoxemic respiratory failure. 3. A patient with an opiate drug overdose is unconscious and has the following ABG results on
room air: pH 7.20; PaCO2 88 mm Hg; PaO2 42 mm Hg; HCO 25 mEq/L. Which of the following best describes this patient’s condition? a. Chronic hypoxemic respiratory failure b. Chronic hypercapnic respiratory failure c. Acute hypoxemic respiratory failure d. Acute hypercapnic respiratory failure ANS: D
A drug overdose will affect the patient’s central nervous system, knocking out the patient’s respiratory center. This will cause an increase in the partial pressure of carbon dioxide in the arteries (PaCO2). The alveolar hypoventilation is causing the low partial pressure of oxygen (PaO2). If this was a chronic hypercapnic respiratory failure the patient’s bicarbonate level would be elevated above the normal level. 4. Acute hypercapnic respiratory failure may be caused by which of the following? a. Decreased fractional inspired oxygen (FIO2) b. Pulmonary shunt c. Respiratory muscle fatigue d. Perfusion/diffusion impairment
ANS: C
A decreased fractional inspired oxygen (FIO2), pulmonary shunt, and perfusion/diffusion impairment will lead to acute hypoxemic respiratory failure. Respiratory muscle fatigue would decrease a patient’s ability to “move air” and would cause acute hypercapnic respiratory failure. 5. Hypercapnic respiratory failure due to increased work of breathing will be caused by which of
the following? Drug overdose Myasthenia gravis Asthma exacerbation Pulmonary embolism
a. b. c. d.
ANS: C
An asthma exacerbation is characterized by bronchoconstriction due to bronchospasm, edema, and inflammation of the airways. This increases the amount of work a patient must do to overcome the increase in airway resistance, thereby increasing the patient’s work of breathing. A drug overdose causes hypercapnic respiratory failure but because of a reduced drive to breathe. Myasthenia gravis is a neuromuscular disease that may paralyze the ventilatory muscles, causing a patient to not be able to move air. A pulmonary embolism would increase dead space by blocking off perfusion to a part of the lung. This would cause acute hypoxemic respiratory failure. 6. A postoperative patient complaining of dyspnea is found to have tachypnea and tachycardia,
and is somewhat confused. Breath sounds reveal end-inspiratory crackles in both lung bases. An arterial blood gas (ABG) is drawn and reveals the following: pH 7.49; PaCO2 33 mm Hg; PaO2 51 mm Hg; SaO2 87%; HCO 25 mEq/L while on a 30% air entrainment mask. The most appropriate respiratory therapy intervention includes which of the following? a. Initiate noninvasive positive pressure ventilation (NIV). b. Initiate continuous positive airway pressure (CPAP) by mask. c. Administer bronchodilator therapy. d. Intubate and mechanically ventilate. ANS: B
This patient is showing signs and symptoms of hypoxemic respiratory failure due to postoperative atelectasis. This patient’s PaO2/FIO2 is below the critical value. Since the patient is still able to move air, intubation and mechanical ventilation, as well as noninvasive positive pressure ventilation (NIV), are not appropriate at this time. This patient is not showing signs of increased work of breathing due to bronchospasm. Therefore, administering bronchodilator therapy is not appropriate. Initiating continuous positive airway pressure (CPAP) by mask will help to reverse the atelectasis and improve the patient’s oxygenation status. 7. A patient with inadequate oxygenation of the brain may display which of the following
conditions? 1. Confusion 2. Excitement 3. Somnolence 4. Compliance a. 1 and 2 only b. 1 and 3 only
c. 2 and 4 only d. 3 and 4 only ANS: B
Confusion and somnolence are neurological findings with severe hypoxemia, which shows that the hypoxemia has affected the patient’s brain. The brain requires approximately 3.3 mL of oxygen per 100 grams of brain tissue per minute. Initially, the body responds to lowered blood oxygen by redirecting blood to the brain and increasing cerebral blood flow. Blood flow may increase up to twice the normal flow but no more. If the increased blood flow is sufficient to supply the brain’s oxygen needs, then no symptoms will result. However, if blood flow cannot be increased or if doubled blood flow does not correct the problem, symptoms of cerebral hypoxia will begin to appear. These symptoms include restlessness, disorientation, headaches, lassitude, somnolence, confusion, delirium, blurred vision, etc. 8. A 28-year-old man is admitted to the emergency department with suspected drug overdose.
The patient is obtunded and slightly cyanotic. The ABG results obtained while the patient was breathing room air were: pH 7.24; PaCO2 58 mm Hg; PaO2 52 mm Hg; HCO 24 mEq/L. The most appropriate interpretation of these results is which of the following? a. Chronic respiratory failure b. Hypoxemic respiratory failure c. Hypercapnic respiratory failure d. Acute or chronic respiratory failure ANS: C
This arterial blood gas shows an uncompensated respiratory acidosis with moderate hypoxemia. A patient with chronic respiratory failure would show an elevated bicarbonate (HCO ) due to the chronic respiratory failure. A patient with acute or chronic respiratory failure would have an elevated partial pressure of carbon dioxide in the arteries (PaCO2) that is higher than what the patient’s current HCO can compensate for. Hypoxemic respiratory failure will only show a decreased partial pressure of oxygen in the arteries (PaO2) unless the hypoxemia is so severe that the patient’s ventilation is compromised. 9. The respiratory assessment of a 44-year-old female patient diagnosed with myasthenia gravis
shows: vital capacity 475 mL, maximum inspiratory pressure (MIP) 18 cm H2O. The patient is 5 feet 6 inches tall and weighs 188 lb. The most recent ABG on a 2 L/min nasal cannula is pH 7.32, PaCO2 49 mm Hg, PaO2 77 mm Hg, SaO2 95%, HCO 24 mEq/L. The most appropriate recommendation for this patient is which of the following? a. 50% air entrainment mask b. Continuous positive airway pressure c. Noninvasive positive pressure ventilation d. Intubation and mechanical ventilation ANS: D
The arterial blood gas result for this patient shows an acute respiratory acidosis. That along with a vital capacity of 7.4 mL/kg and the maximum inspiratory pressure (MIP) of 18 cm H2O point to the fact that this patient is also showing signs of muscle weakness that is progressively worsening. This requires prompt intubation and support to prevent acute respiratory failure. The 50% air entrainment mask and the continuous positive airway pressure (CPAP) will not provide support for this patient’s ventilatory problems. Noninvasive positive pressure ventilation (NIV) is not appropriate for this patient because of the patient’s decreasing muscle strength. 10. Which of the following values are indicative of acute respiratory failure and the need for
ventilatory support? 1. Maximum inspiratory pressure 2. Dead space-to-tidal volume ratio 3. Vital capacity 4. pH = 7.20 a. 1 and 2 only b. 2 and 3 only c. 3 and 4 only d. 1 and 4 only ANS: C
The critical values for the parameters listed are maximum inspiratory pressure (MIP) 20 to 0, dead space-to-tidal volume , vital capacity ideal body weight (IBW), and . 11. A 46-year-old male presents to the emergency department with a chief complaint of shortness
of breath. Physical assessment reveals: pulse 102 beats/min, blood pressure 138/80 mm Hg, respiratory rate 25 breaths/min with accessory muscle use, and breath sounds are decreased with bilateral inspiratory and expiratory wheezing with a prolonged expiratory phase. The peak expiratory flow rate is 100 L/min. The immediate action by the respiratory therapist should include which of the following? a. Intubate and mechanically ventilate. b. Administer oxygen via nonrebreather mask. c. Administer continuous bronchodilator therapy. d. Initiate noninvasive positive pressure ventilation. ANS: C
It would be inappropriate at this time to intubate this patient because he is still moving air, as evidenced by his respiratory rate and breath sounds (although he may be tiring). Noninvasive ventilation is not appropriate for the same reasons. An arterial blood gas is necessary to establish the need for mechanical ventilation. This patient appears to be having an asthma exacerbation, as evidenced by his bilateral wheezing with a prolonged expiratory phase. The patient would probably benefit from oxygen therapy. However, the immediate problem and cause for alarm is his severe airflow obstruction, as evidenced by his breath sounds and peak expiratory flow rate (PEFR). Therefore, the most appropriate answer is to administer continuous bronchodilator therapy.
12. A 64-year-old female patient having an acute exacerbation of chronic obstructive pulmonary
disease (COPD) was admitted to the hospital yesterday. During rounds today the respiratory therapist finds the patient to be difficult to arouse and has the following physical findings: heart rate 102 beats/min, respiratory rate 23 breaths/min shallow and slightly labored, breath sounds are bilaterally decreased with rhonchi in both bases. The patient has a frequent but weak cough. The respiratory therapist draws an ABG with the following results on a 2 L/min nasal cannula: pH 7.52, PaCO2 30 mm Hg, PaO2 45 mm Hg, SaO2 86%, HCO 24 m Eq/L. The most appropriate action is which of the following? a. Intubate and mechanically ventilate. b. Increase the nasal cannula to 4 L/min. c. Administer incentive spirometry. d. Begin noninvasive positive pressure ventilation. ANS: B
It would be inappropriate to intubate or use noninvasive positive pressure ventilation (NIV) on this patient at this time because the patient is able to move air, as evidenced by the partial pressure of carbon dioxide (PaCO2) of 30 mm Hg in the arteries. This patient might benefit from lung expansion therapy. However, she would not be able to cooperate to perform the incentive spirometry properly because she is difficult to arouse. The patient would benefit from an increase in oxygen therapy by increasing the nasal cannula flow to 4 L/min since her partial pressure of oxygen in the arteries (PaO2) is 45 mm Hg on 2 L/min nasal cannula. When the 2 L/min is estimated to be approximately 28% oxygen the PaO2/FIO2 is 161. This is a critical value. This patient would also benefit from bronchial hygiene therapy to mobilize the retained secretions. 13. A 55-year-old male with acute dyspnea is admitted to the hospital. He is alert and oriented.
His physical examination reveals: heart rate 120 beats/min and regular; blood pressure 146/88 mm Hg; temperature 38 C; respiratory rate 28 breaths/min shallow and labored. Breath sounds are decreased throughout with fine late crackles on inspiration, chest expansion is decreased in both bases. The patient is not coughing. The ABG on room air is: pH 7.52; PaCO2 30 mm Hg; PaO2 42 mm Hg; Hb-O2 80%; HCO 24 mEq/L. This patient is retired after working in a steel factory for 38 years and he has a 50-pack-year history of smoking. The most appropriate action for the respiratory therapist to take is which of the following? a. Intubate and initiate positive pressure ventilation. b. Initiate noninvasive positive pressure ventilation. c. Administer oxygen via a high flow nasal cannula. d. Initiate bronchodilator and mucolytic therapy. ANS: C
According to the arterial blood gas (ABG) this patient is able to move air as evidenced by a partial pressure of carbon dioxide (PaCO2) of 30 mm Hg (respiratory alkalosis); therefore intubation and artificial ventilation are not necessary. The patient does not require noninvasive positive pressure ventilation (NIV), because he is breathing. The patient does not seem to have evidence of requiring a bronchodilator and a mucolytic. The patient does, however, have moderate hypoxemia. Since the patient is not a carbon dioxide (CO2) retainer, a high concentration of oxygen may be applied in the form of high flow nasal cannula.
14. A 28-year-old female was admitted last night for weakness and what appears to be ascending
muscle paralysis. The patient is alert and oriented. Physical findings reveal: pulse 96 beats/min, regular; blood pressure 134/83 mm Hg; temperature 37 C; respiratory rate 24 breaths/min shallow with bilateral decrease in air entry; and no adventitious breath sounds. The patient’s ABG results on room air are: pH 7.46; PaCO2 39 mm Hg; PaO2 80 mm Hg; Sat 97%; and HCO 26 mEq/L on room air. The most appropriate suggestion that the respiratory therapist should make for this patient includes which of the following? a. Vital capacity every 2 hours b. Continuous positive airway pressure c. Noninvasive positive pressure ventilation d. Peak expiratory flow rate ANS: A
Although this patient is suffering from a neuromuscular disease, the patient’s arterial blood gas results are within normal limits and therefore do not warrant the use of continuous positive airway pressure (CPAP) or noninvasive positive airway pressure (NIV). Peak expiratory flow rate is most frequently used to assess airway resistance for patients with acute asthma. This patient requires frequent monitoring to assess her respiratory muscle strength, and that would be within the vital capacity. 15. An 80-year-old female with a diagnosis of pneumonia was admitted to the hospital 2 days ago
from a nursing home. The patient is responsive only to painful stimuli. She has a peripheral IV and a feeding tube in place. Physical examination reveals: pulse 98 beats/min; respiratory rate 24 breaths/min and shallow; blood pressure 100/48 mm Hg; and temperature 39.2 C. Auscultation reveals decreased breath sounds with crackles in the bases. The patient has an occasional weak, nonproductive cough. Arterial blood gas on NC 4 L/min is pH 7.42, PaCO2 38 mm Hg, PaO2 40 mm Hg, SaO2 76%, HCO 24 mEq/L. A portable chest X-ray shows patchy basilar infiltrates in both lungs. The most appropriate action to take at this time is which of the following? a. Intubate and initiate mechanical ventilation. b. Administer a bronchodilator and mucolytic. c. Initiate noninvasive positive pressure ventilation. d. Change the nasal cannula to a nonrebreather mask. ANS: D
According to the arterial blood gas (ABG) this patient has a normal acid–base balance; therefore intubation and artificial ventilation are not necessary. The patient does not seem to have evidence of requiring a bronchodilator and mucolytic. The patient does not require noninvasive positive airway pressure ventilation (NIV), because he is breathing. The patient does, however, have severe hypoxemia that warrants a high oxygen concentration.
16. The first arterial blood gas for an asthma patient in the emergency department reveals: pH
7.49; PaCO2 30; PaO2 82; SaO2 95%; HCO 24 on a nasal cannula 3 L/min. The patient’s peak expiratory flow rate was 165 L/min, respiratory rate was 16 breaths/min, and pulse 106 beats/min. After continuous aerosolized albuterol over the past hour, the patient’s current ABG results are as follows: pH 7.34; PaCO2 45; PaO2 49; SaO2 79%; HCO 25 on a high flow nasal cannula 15 L/min. The patient’s peak expiratory flow rate is 95 L/min, respiratory rate 35 breaths/min, pulse 128 beats/min, and the patient is diaphoretic. The respiratory therapist should suggest which of the following at this time? a. Change to a nonrebreather mask. b. Begin continuous positive airway pressure. c. Intubate and initiate mechanical ventilation. d. Initiate noninvasive positive pressure ventilation. ANS: C
This patient’s airway obstruction is worsening as evidenced by the deterioration in the patient’s acid–base status, oxygenation status, and peak expiratory flow rate. The patient has also developed tachycardia, tachypnea, and sweating. The critical values are partial pressure of oxygen in the arteries (PaO2), peak expiratory flow rate (PEFR), respiratory rate (RR), and pulse. This patient is now in impending ventilatory failure and meets the standard criteria for instituting mechanical ventilation (see Box 4-5). Changing oxygen delivery devices to a nonrebreather mask will not increase the fractional inspired oxygen (FIO2) delivered. Continuous positive airway pressure may address the patient’s oxygenation problem; however, it will not help to improve the patient’s increased work of breathing. 17. A patient seen in the emergency department exhibits paralysis of the lower extremities that is
getting progressively worse. Vital capacity is 6 mL/kg, maximum inspiratory pressure (MIP) is 17 cm H2O, and oxygen saturation measured by pulse oximeter (SpO2) is 89%. Arterial blood gases are pending. The physician suspects Guillain-Barré syndrome. The most appropriate action at this time is which of the following? a. Intubate and mechanically ventilate. b. Place patient on a nonrebreather mask. c. Initiate continuous positive airway pressure. d. Initiate noninvasive positive pressure ventilation. ANS: A
This patient’s maximum inspiratory rate (MIP) and vital capacity (VC) measurements are both critical. Since the patient has a progressive neuromuscular disease with these critical values and a below normal pulse oximetry reading, this patient should be intubated and mechanically ventilated before the patient develops an acute situation. Placing the patient on a nonrebreather mask or initiating continuous positive airway pressure (CPAP) will not address the fact that the neuromuscular disease is now beginning to affect this patient’s ventilator muscle strength. Since protection of the airway may become an issue, invasive ventilation would be the most appropriate action. 18. Which of the following values are indicative of acute respiratory failure and the need for
ventilatory support? 1. Maximum inspiratory pressure (MIP) = 38 cm H2O. 2. Vital capacity (VC) = 650 mL for a 70 kg male. 3. Alveolar-to-arterial partial pressure of oxygen [P
O2] = 150 on 100% oxygen.
4. Maximum expiratory pressure (MEP) = 25 cm H2O. 1 and 2 only 2 and 4 only 1 and 3 only 3 and 4 only
a. b. c. d.
ANS: B
The critical values for the parameters listed are: maximum inspiratory pressure ; vital capacity (VC) <10–15 mL/kg ideal body weight (IBW); alveolar-to-arterial partial pressure [P
O2] >450 on O2, and maximum expiratory pressure (MEP) <40 cm H2O.
19. The disorders that cause respiratory failure due to increased work of breathing include which
of the following? 1. Myasthenia gravis 2. Cardiogenic pulmonary edema 3. Interstitial pulmonary fibrosis 4. Amyotrophic lateral sclerosis a. 1 and 2 only b. 2 and 3 only c. 3 and 4 only d. 1 and 4 only ANS: B
Myasthenia gravis and amyotrophic lateral sclerosis are two neuromuscular disorders that cause respiratory failure through muscle weakness and paralysis. Both cardiogenic pulmonary edema and interstitial pulmonary fibrosis cause respiratory failure through increased work of breathing. 20. A 52-year-old male with a medical history of congestive heart failure and hypertension arrives
in the emergency department because of an acute onset of dyspnea. The patient has pink frothy secretions at the mouth. A rapid physical assessment reveals a pulse of 128 beats/min, respiratory rate 28 breaths/min and labored, and blood pressure 82/56 mm Hg. Bilateral coarse crackles are heard in the lung bases. Arterial blood gas results on a 12 L/min nonrebreather mask are: pH 7.32, PaCO2 49 mm Hg, PaO2 50 mm Hg, arterial SaO2 74%. The most appropriate immediate action for this patient is which of the following? a. Intubation and mechanical ventilation b. Increase flow to the nonrebreather mask c. Continuous positive airway pressure via mask d. Nasotracheal suctioning and a high flow nasal cannula ANS: A
This patient is hypoxemic with a nonrebreather mask and is also unable to move a sufficient amount of air. This is evidenced by the patient’s partial pressure of oxygen in the arteries (PaO2) of 50 mm Hg and partial pressure of carbon dioxide in the arteries (PaCO2) of 49 mm Hg. Three out of the four oxygenation criteria are below the critical values. The pink frothy sputum is cardiogenic pulmonary edema and the hypotension is caused by cardiogenic shock. This is a medical emergency requiring intubation, mechanical ventilation, and positive endexpiratory pressure (PEEP). Increasing the flow of oxygen to the nonrebreather, continuous positive airway pressure (CPAP) via mask, nasotracheal suctioning, and a high flow nasal cannula will not reverse this patient’s oxygenation or ventilation issues.
21. A 45-year-old woman arrives in the emergency department after ingesting an unknown
quantity of pain medication and alcohol. Her friend found her unconscious in her apartment. She is currently unresponsive to verbal stimuli. Vital signs reveal: pulse 56 beats/min; respiratory rate 10 breaths/min and shallow; and BP 90/50 mm Hg. Her ABG on room air reveals: pH 7.21; PaCO2 64 mm Hg; PaO2 52 mm Hg, HCO 24 mEq/L. The appropriate treatment for this patient includes which of the following? 1. Naloxone hydrochloride (Narcan) 2. Nasal cannula 4 L/min 3. Nonrebreather mask 4. Intubation and ventilatory support a. 2 only b. 4 only c. 1 and 3 only d. 1 and 4 only ANS: D
The arterial blood gas (ABG) values indicate that this patient has acute respiratory failure because the patient is not moving air, as evidenced by the partial pressure of carbon dioxide in the arteries (PaCO2) of 64 mm Hg. This patient also has hypoxemic respiratory failure due to the hypercapnic respiratory failure. Since this is the case, plus the fact that the patient is unconscious due to a drug overdose, the patient’s airway must be protected. Therefore, intubation and ventilatory support are necessary to protect the airway and maintain the patient’s ventilations until she wakes up. To assist in reversing the central nervous system (CNS) and ventilatory depression, naloxone hydrochloride should be given. This drug is an opioid antagonist. The oxygen devices suggested in the answers are not appropriate because they will not address the patient’s hypercapnic respiratory failure. 22. A 59-year-old patient is in severe respiratory distress in the emergency department. The
patient is being treated for congestive heart failure and pulmonary edema. Vital signs are pulse 98 beats/min, respiratory rate 23 breaths/min, and BP 138/98 mm Hg. The patient’s ABG results on a nonrebreather mask are as follows: pH 7.35; partial PaCO2 45 mm Hg; PaO2 49 mm Hg; SaO2 79%; and HCO 24 mEq/L. The respiratory therapy that is most appropriate at this time is which of the following? a. 6 L/min nasal cannula b. 50% air entrainment mask c. Mask continuous positive airway pressure (CPAP) with 100% oxygen. d. Intubate and mechanically ventilate. ANS: C
This patient’s oxygenation is not responding well to the nonrebreather mask. This is indicative of refractory hypoxemia. The next step in the treatment of a patient with congestive heart failure (CHF) who is moving air would be to use a continuous positive airway pressure (CPAP) mask with supplemental oxygen. CPAP is very effective in the treatment of hypoxemia caused by heart failure. It can relieve some of the vascular congestion, reduce the patient’s work of breathing, and improve gas exchange. This patient is not quite a candidate for intubation and mechanical ventilation because he is still moving air as evidenced by his partial pressure of carbon dioxide in the arteries (PaCO2) of 45 mm Hg. Both the nasal cannula and air entrainment mask, in this case, are a step backward in the management of this patient.
23. Which of the following patients is showing the signs of acute respiratory distress? a. One who is in a semi-Fowler position, watching TV, with a 2 L/min nasal cannula b. One who is in the high Fowler position, diaphoretic, anxious, and unable to
complete a sentence c. One who is leaning forward on a table, using accessory muscles, and purse-lip
breathing d. One who is in the high Fowler position, with a 2 L/min nasal cannula, eating
breakfast ANS: B
The patient who is sitting upright, who is diaphoretic, anxious, and unable to speak in full sentences is most likely in acute respiratory distress. The patient who is leaning forward with accessory muscle use and pursed lips is most likely a patient with chronic respiratory distress. The two other patients, although they are receiving oxygen, do not seem to be having a hard time breathing. 24. A 28-year-old man with botulism poisoning is beginning to develop progressive paralysis. The
respiratory therapist has been monitoring the patient’s MIP and VC every 2 hours. The most recent results show that the patient continues to deteriorate: MIP = 27 cm H2O, VC = 32 mL/kg. Which of the following could be appropriately recommended? a. Gastric lavage b. Oxygen therapy c. Medication to reverse the paralysis d. Mechanical ventilatory support ANS: D
The critical values for the parameters listed are: maximum inspiratory pressure (MIP) 20 to 0; vital capacity (VC) <10–15 mL/kg ideal body weight (IBW); alveolar-to-arterial partial pressure on O2; and maximum expiratory pressure patient’s condition is worsening and requires mechanical ventilatory support.
. This
25. Which of the following are goals of mechanical ventilation?
1. To provide support to the pulmonary system to maintain an adequate level of alveolar ventilation 2. To reduce the WOB until the cause of respiratory failure can be eliminated 3. To restore ABG levels to normal 4. To prevent or treat atelectasis with adequate end-inspiratory lung inflation a. 1 and 2 only b. 1 and 3 only c. 1, 2, and 3 only d. 1, 2, and 4 only ANS: D
Physiological Objectives 1. Support or manipulate pulmonary gas exchange: • Alveolar ventilation—Achieve eucapnic ventilation or allow permissive hypercapnia (Note: Permissive hypercapnia sometimes is required in the ventilation of patients with asthma, acute lung injury [ALI], or acute respiratory distress syndrome [ARDS] to protect the lung by avoiding high ventilating volumes and pressures.)
Alveolar oxygenation—Maintain adequate oxygen delivery (CaO2 Cardiac output). Increase lung volume: • Prevent or treat atelectasis with adequate end-inspiratory lung inflation. • Restore and maintain an adequate functional residual capacity (FRC). 3. Reduce the work of breathing. Clinical Objectives 1. Reverse acute respiratory failure. 2. Reverse respiratory distress. 3. Reverse hypoxemia. 4. Prevent or reverse atelectasis and maintain FRC. 5. Reverse respiratory muscle fatigue. 6. Permit sedation or paralysis (or both). 7. Reduce systemic or myocardial oxygen consumption. 8. Minimize associated complications and reduce mortality. •
2.
26. A 14-year-old boy who had previously been diagnosed with mild persistent asthma has a
PEFR of 100 L/min. This indicates which of the following? a. Increased airway resistance b. Heart failure c. Increased lung compliance d. Inability to take in a deep breath and cough ANS: A
For patients with acute asthma, the PEFR is the most frequently used parameter to assess airway resistance. Peak expiratory flow rate 350–600 (normal) 75–100 (critical value) (PEFR) (L/min) 27. After oxygen is administered, a patient’s heart rate changes from 110 to 85 beats/min. The
initial tachycardia was most likely caused by which of the following? Anxiety Hypoxemia Hypercapnia Pain
a. b. c. d.
ANS: B
Tachycardia is a sign of hypoxemia. Once the hypoxemia is corrected, their heart rate typically improves.
Chapter 05: Selecting the Ventilator and the Mode Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. A 68-year-old female admitted for congestive heart failure is in respiratory distress and is
being seen by the hospital’s medical emergency team in her regular room. The patient is in obvious respiratory distress and is immediately placed on a nonrebreather mask. Physical assessment reveals: pulse 138 and thready; respiratory rate 30, shallow and labored; temperature 37 C; blood pressure 110/68. Breath sounds are bilaterally decreased with coarse crackles on inspiration. EKG shows normal sinus rhythm with widened cardiac output (QT) interval and an occasional irregular beat. No coughing is noted. The arterial blood gas on the nonrebreather mask is: pH 7.34; PCO2 46 mm Hg; partial pressure of oxygen in the arteries (PaO2) is 52 mm Hg; oxygen saturation is 86%; bicarbonate (HCO ) is 24 mEq/L. The patient is diaphoretic. The most appropriate ventilator mode to manage this patient initially is which of the following? a. Noninvasive positive pressure ventilation (NIV) b. Airway pressure release ventilation (APRV) c. Volume-controlled intermittent mandatory ventilation (VC-IMV) d. Pressure-controlled intermittent mandatory ventilation (PC-IMV) ANS: A
This patient is in impending respiratory failure due to a congestive heart failure (CHF) exacerbation. The arterial blood gas (ABG) also reveals mild hypercapnia and severe hypoxemia. With the proper treatment this exacerbation could be reversed fairly quickly. Noninvasive positive pressure ventilation (NIV), in the form of bilevel positive airway pressure, is appropriate because of this. All the other choices require intubation. If the NIV doesn’t work to decrease the patient’s respiratory failure then intubation would be the next step. 2. A patient has recently been diagnosed with obstructive sleep apnea. The most appropriate
treatment includes which of the following? Pressure support ventilation (PSV) Noninvasive positive pressure ventilation (NIV) Continuous positive airway pressure (CPAP) Pressure-controlled continuous mandatory ventilation (PC-CMV)
a. b. c. d.
ANS: C
Continuous positive airway pressure (CPAP) is an accepted method used to treat obstructive sleep apnea. Noninvasive positive pressure ventilation (NIV) would be appropriate if the patient had central sleep apnea, since there would be no respiratory efforts during the apnea periods. Pressure support ventilation (PSV) and pressure-controlled continuous mandatory ventilation (PC-CMV) would require the patient to be intubated. 3. Which of the following is the minimum ventilator rate that is considered full ventilatory
support? a. 4 breaths/min b. 6 breaths/min
c. 8 breaths/min d. 10 breaths/min ANS: C
Full ventilatory support is provided when the ventilator-initiated rates are 8 breaths/min or more. 4. Partial ventilatory support can be provided by which of the following ventilator modes?
1. Pressure-controlled continuous mandatory ventilation (PC-CMV) set rate 8 breaths/min 2. Volume-controlled intermittent mandatory ventilation (VC-IMV) set rate 4 breaths/min 3. Pressure-controlled intermittent mandatory ventilation (PC-IMV) set rate 10 breaths/min 4. VC-MMV set Ve8 L/min a. 1 and 2 only b. 2 and 3 only c. 2 and 4 only d. 3 and 4 only ANS: C
Continuous mandatory ventilation (CMV) is a full ventilatory support mode. Therefore, a pressure-controlled continuous mandatory ventilation (PC-CMV) rate of 8 breaths/min is not partial ventilatory support. A ventilator rate setting of 8 breaths/min or more is also considered full support. Therefore, even though pressure-controlled intermittent mandatory ventilation (PC-IMV) could be partial ventilatory support, it is full support because of the set rate of 10 breaths/min. Volume-controlled intermittent mandatory ventilation (VC-IMV) with a set rate of 4 breaths/min is partial ventilatory support and MMV can be partial ventilatory support when the patient is participating in the work of breathing (WOB) to maintain effective alveolar ventilation. 5. Of the following breath descriptions, which one is considered spontaneous? a. Flow triggered, pressure limited, flow cycled b. Time triggered, volume limited, volume cycled c. Pressure triggered, pressure limited, time cycled d. Patient triggered, patient cycled, baseline pressure +5 cm H2O ANS: D
Flow triggered and pressure triggered mean that the patient has initiated the breath. Pressure limited and volume limited mean that either one of these variables is not allowed to be exceeded during a breath. This occurs with either ventilator or assisted breaths. Patient triggered could either be pressure or flow and could be part of a spontaneous breath as long as the pressure during inspiration does not rise above the baseline setting. During spontaneous breathing the patient will control both the beginning and the ending of the breath. 6. What type of breath occurs when the ventilator controls the timing, tidal volume, or
inspiratory pressure? Assisted Mandatory Spontaneous Controlled
a. b. c. d.
ANS: B
Mandatory breaths occur when the ventilator is time triggered, volume or pressure targeted. Spontaneous breaths are patient triggered, and the volume or pressure is based on the patient’s demand and lung characteristics. Assisted breaths have characteristics of both mandatory and spontaneous, the patient triggers the breath, the ventilator delivers a set pressure or volume, and the airway pressure rises above baseline during inspiration. The term control is not used to describe the type of breath delivery. This term is used to describe the variable that is being manipulated as the target for the breaths (e.g., pressure control or volume control). 7. A homecare patient diagnosed with central sleep apnea would benefit from which of the
following modes of ventilation? Pressure support ventilation (PSV) Noninvasive positive pressure ventilation (NIV) Continuous positive airway pressure (CPAP) Pressure-controlled intermittent mandatory ventilation (PC-IMV)
a. b. c. d.
ANS: B
Noninvasive positive pressure ventilation (NIV) is appropriate for this patient because during the periods of apnea there are no respiratory efforts. Continuous positive airway pressure (CPAP) is an accepted method used to treat obstructive sleep apnea. Pressure support ventilation (PSV) and pressure-controlled intermittent mandatory ventilation (PC-CMV) would require the patient to be intubated. 8. During volume control ventilation a patient’s airway resistance increases. This change will
cause which of the following to occur? a. Increase in delivered volume b. Increase in peak airway pressure c. Decrease in plateau pressure d. Decrease in peak airway pressure ANS: B
During volume control ventilation, changes in lung characteristics cause changes in pressure. Increasing airway resistance causes an increase in the amount of pressure required to deliver the volume, thereby increasing peak airway pressure. 9. A 28-year-old male has arrived in the emergency department following a motor vehicle
accident. He has a Glasgow Coma Score of 14. Chest X-ray reveals five ribs broken anteriorly in two areas each. Physical assessment reveals paradoxical movement of the chest. Breath sounds are diminished and the trachea is midline. Arterial blood gas on nonrebreather mask is: pH 7.53, partial pressure of carbon dioxide (PaCO2) is 25 mm Hg, partial pressure of oxygen (PaO2) is 59 mm Hg, arterial oxygen saturation (SaO2) 93%, bicarbonate (HCO ) 23 mEq/L. The respiratory therapist should recommend which of the following for this patient? a. Noninvasive positive pressure ventilation (NIV) with supplemental oxygen b. Intubation with volume-controlled continuous mandatory ventilation (VC-CMV) with positive end-expiratory pressure (PEEP) c. Mask continuous positive airway pressure (CPAP) with supplemental oxygen. d. Intubation with CPAP and pressure support ANS: C
The arterial blood gas shows that the patient is ventilating, as evidenced by the partial pressure of carbon dioxide (PaCO2) of 25 mm Hg. Therefore, this patient does not need to be intubated and ventilated at this time. This also means that the patient does not require noninvasive positive pressure ventilation (NIV). The patient does have an oxygenation problem, as evidenced by the partial pressure of oxygen (PaO2) of 59 mm Hg while on a nonrebreather mask. This is an indication for continuous positive airway pressure (CPAP). 10. An assisted breath in the pressure-controlled continuous mandatory ventilation (PC-CMV)
mode can be described by which of the following? Time triggered, pressure limited, time cycled Patient triggered, pressure limited, time cycled Time triggered, pressure limited, pressure cycled Patient triggered, volume limited, volume cycled
a. b. c. d.
ANS: B
An assisted breath is always patient triggered. In the pressure control or targeted mode the pressure set is the pressure limit and the inspiratory time setting ends inspiration (cycle). Therefore, the correct answer is patient triggered, pressure limited, time cycled. The time triggered, pressure limited, and time cycled breath is a mandatory breath in the pressurecontrolled continuous mandatory ventilation (PC-CMV) mode. The time triggered, pressure limited, and pressure cycled breath describes an intermittent positive pressure breathing (IPPB)-type mandatory breath. The patient triggered, volume limited, and volume cycled is a mandatory breath in the volume-controlled continuous mandatory ventilation (VC-CMV) mode. 11. The ventilator mode that allows the patient to breathe spontaneously between operator-
selected time-triggered volume and pressure-targeted breaths is which of the following? Pressure support ventilation (PSV) Continuous mandatory ventilation (CMV) Intermittent mandatory ventilation (IMV) Airway pressure release ventilation (APRV)
a. b. c. d.
ANS: C
The intermittent mandatory ventilation (IMV) mode allows the patient to breathe spontaneously between operator mandatory ventilator breaths. During these spontaneous breaths the baseline pressure may be set at ambient pressure or above ambient pressure. In addition, pressure support may be used during the spontaneous breathing period. Pressure support ventilation (PSV) has no time-triggered breaths, nor does it have volume-targeted breaths. Continuous mandatory ventilation (CMV) does not allow for spontaneous breathing; it only allows the patient to trigger the mandatory ventilator breath. Airway pressure release ventilation (APRV) does not have volume-targeted breaths. It is designed to be two levels of continuous positive airway pressure (CPAP) where the patients breathe spontaneously at both levels. 12. A hemodynamically unstable patient being ventilated in the volume-controlled continuous
mandatory ventilation (VC-CMV) mode is triggering inspiration at a rate of 25 breaths/min and has the following arterial blood gas results: pH 7.50, partial pressure of carbon dioxide (PaCO2) 30 mm Hg, partial pressure of oxygen (PaO2) 98 mm Hg, arterial oxygen saturation (SaO2) 100%, bicarbonate (HCO ) 24 mEq/L. The respiratory therapist should perform which of the following?
a. Extubate and administer noninvasive positive pressure ventilation (NIV). b. Change the mode to pressure-controlled continuous mandatory ventilation (PC-
CMV). c. Change the mode to volume-controlled intermittent mandatory ventilation (VC-
IMV). d. Sedate and paralyze the patient. ANS: C
This patient has ventilator-induced hyperventilation as evidenced by the partial pressure of carbon dioxide (PaCO2) of 30 mm Hg with a trigger rate of 25 breaths/min. Switching to the volume-controlled intermittent mandatory ventilation (VC-IMV) mode will decrease the number of ventilator breaths the patient triggers by allowing the patient to breathe spontaneously between the mandatory ventilator breaths. This will reduce the patient’s minute ventilation and normalize the PaCO2 and pH. Another potential advantage is to put less of a strain on an already hemodynamically unstable patient. There is nothing in this patient’s scenario that suggests extubation and use of noninvasive positive pressure ventilation (NIV). Switching to the pressure-controlled continuous mandatory ventilation (PC-CMV) mode will most likely not correct the patient’s problem because the patient will still be able to trigger ventilator set breaths and could continue to hyperventilate. Although sedating and medically paralyzing the patient could normalize the patient’s acid–base balance, it is not the treatment of choice because of the hemodynamic instability of the patient. 13. The pressure–time scalar shown in the figure represents which of the following?
a. Airway pressure release ventilation (APRV) b. Volume-controlled intermittent ventilation (VC-IMV) with positive end-expiratory
pressure (PEEP) c. Pressure-controlled intermittent mandatory ventilation (PC-IMV) with positive
end-expiratory pressure (PEEP) d. Bilevel positive airway pressure ANS: C
The figure shows two levels of pressure-control ventilation. The higher level, around 22 cm H2O, is the mandatory ventilator breaths. The lower level shows spontaneous breaths with a pressure support of approximately 15 cm H2O. Baseline (PEEP) is at 5 cm H2O. 14. Full ventilatory support is provided by which of the following modes? a. Pressure support ventilation (PSV) with continuous positive airway pressure
(CPAP) b. Volume support ventilation (VSV) with continuous positive airway pressure
(CPAP)
c. Volume-controlled intermittent mandatory ventilation (VC-IMV) rate 6 with
pressure support (PS) d. Pressure-controlled intermittent mandatory ventilation (PC-IMV) rate 12 with
pressure support (PS) ANS: D
Full ventilatory support is provided when the ventilator-initiated rates are set at 8 breaths/min or more in the continuous mandatory ventilation (CMV) or intermittent mandatory ventilation (IMV) modes with either pressure control or volume control. 15. The ventilator mode that would be most appropriate to iatrogenically induce hyperventilation
to manage a closed head injury patient with severely elevated intracranial pressure (ICP) is which of the following? a. Volume support ventilation (VSV) b. Airway pressure release ventilation (APRV) c. Pressure-controlled continuous mandatory ventilation (PC-CMV) d. Volume-controlled intermittent mandatory ventilation (VC-IMV) ANS: C
To deliberately hyperventilate a patient, each breath needs to be a machine breath (either volume or pressure). The only mode from the choices given that does that is the pressurecontrolled continuous mandatory ventilation (PC-CMV) mode. Volume support ventilation (VSV) is a patient triggered, volume targeted, flow cycled mode of ventilation that has no backup rate and therefore is a purely spontaneous mode. Airway pressure release ventilation (APRV) is designed to provide two levels of continuous positive airway pressure (CPAP) and to allow spontaneous breathing at both levels when spontaneous effort is present. If the patient is not breathing spontaneously, APRV resembles pressure-controlled inverse ratio ventilation (PCIRV) and could potentially elevate the patient’s already elevated intracranial pressure (ICP). Volume-controlled intermittent mandatory ventilation (VC-IMV) actually could be made to hyperventilate the patient if the rate is set high enough. The IMV mode is actually used to reduce the effect of patient hyperventilation on acid–base balance. This happens because only the set rate is a ventilator breath; the rest are patient triggered with the patient’s own tidal volume. 16. If flow or sensitivity is set incorrectly, which of the following is most likely to occur during
the continuous mandatory ventilation (CMV) mode? Muscle atrophy Respiratory alkalosis Ventilator asynchrony Increase in mean airway pressure
a. b. c. d.
ANS: C
High or low flow rate settings can cause the patient to be out of synchrony with the ventilator. The higher the flow rate the shorter the inspiratory time. Incorrect sensitivity settings can lead to autotriggering or “locking out” the patient. 17. In which of the following situations would NIV be tried? a. Patient in whom blood pressure is 65/35, heart rate is 150 beats/min, and
respiratory frequency is 34 breaths/min b. Patient who nearly drowned who has copious amounts of white, frothy secretions c. Patient with chronic obstructive pulmonary disease (COPD) and right lower-lobe
pneumonia with respiratory acidosis and increased work of breathing (WOB) d. A 5-year-old child who has aspirated a piece of chicken and is having trouble breathing ANS: C
In many cases, clinicians prefer using noninvasive positive pressure ventilator support in the form of bilevel positive airway pressure (bilevel PAP) rather than CPAP for patients with Rawinduced auto-PEEP. Bilevel PAP also is the method most often used to treat acute-on-chronic respiratory failure. 18. A breath that is triggered, limited, and cycled by the mechanical ventilator is which of the
following? Assisted breath Mandatory breath Spontaneous breath Breath
a. b. c. d.
ANS: B
Breaths that are triggered by the mechanical ventilator are considered mandatory breaths because the ventilator is controlling the timing of the breath and delivering either a set volume or set pressure. 19. A breath that is patient triggered, pressure targeted, and time cycled is which of the following? a. Assisted breath b. Mandatory breath c. Spontaneous breath d. Breath ANS: A
Assisted breaths have characteristics of both mandatory and spontaneous breaths. In an assisted breath, all or part of the breath is generated by the ventilator, which does part of the work of breathing (WOB) for the patient. If the airway pressure rises above baseline during inspiration, which it does in this case, the breath is assisted. 20. Which mode of ventilation is shown in the pressure–time scalar in the figure?
a. b. c. d.
Pressure-controlled continuous mandatory ventilation (PC-CMV) Volume-controlled continuous mandatory ventilation (VC-CMV) Pressure-controlled intermittent mandatory ventilation (PC-IMV) Volume-controlled intermittent mandatory ventilation (VC-IMV)
ANS: B
The pressure–time scalar shows all mandatory breaths, two time triggered and one pressure triggered. This means there is a combination of mandatory and assisted breaths. The scalar shows a peak inspiratory pressure that is not held. This means that the mode being shown is volume-controlled continuous mandatory ventilation (VC-CMV). 21. Which mode of ventilation is shown in the pressure–time scalar in the figure?
a. Pressure-controlled intermittent mandatory ventilation (PC-IMV) with pressure
support (PS) b. Volume-controlled intermittent mandatory ventilation (VC-IMV) with pressure
support (PS) c. Pressure-controlled continuous mandatory ventilation (PC-CMV) d. Airway pressure release ventilation (APRV) ANS: B
This graph shows two assisted mandatory breaths that have peak pressures. These are volume control breaths that are with the patient. The flat top waves are pressure targeted breaths that are indicative of pressure support. Therefore, there are mandatory breaths with spontaneous pressure supported breaths. This makes the mode volume-controlled intermittent mandatory ventilation (VC-IMV) with pressure support. 22. A patient triggered, pressure limited, flow cycled breath describes which of the following? a. Spontaneous breath b. Pressure support breath c. Volume-control breath d. Pressure-control breath ANS: B
The term pressure limited points to either a pressure support breath or a pressure control breath. These breaths both are limited by the operator-selected pressure. A spontaneous breath is always flow cycled. This eliminates the pressure control breath because those breaths are always time cycled. Therefore, a patient triggered, pressure limited, flow cycled breath is a pressure support breath. 23. When a patient is to be switched from continuous mandatory ventilation (CMV) to
intermittent mandatory ventilation (IMV) to facilitate weaning from mechanical ventilation, which of the following could be used in addition to IMV to assist this process? a. Continuous positive airway pressure (CPAP) b. Positive end-expiratory pressure (PEEP) c. Pressure support (PS) d. Pressure control (PC)
ANS: C
Spontaneous breaths during intermittent mandatory ventilation (IMV) can be supported with pressure support if the clinician wants to reduce the work of breathing (WOB) for the spontaneous breath. 24. Every breath from the ventilator is time or patient triggered, pressure limited, and time cycled.
This describes which of the following ventilator modes? Pressure support ventilation (PSV) Continuous positive airway pressure (CPAP) Pressure-controlled continuous mandatory ventilation (PC-CMV) Volume-controlled intermittent mandatory ventilation (VC-IMV)
a. b. c. d.
ANS: C
A mode in which the patient can receive a time triggered breath or a patient triggered breath is continuous mandatory ventilation (CMV or A/C). Pressure limited breaths that are either time or patient triggered occur in pressure-controlled continuous mandatory ventilation (PC-CMV), where the breath is also time cycled. Pressure support ventilation (PSV) breaths are always flow cycled. Continuous positive airway pressure (CPAP) breaths are always spontaneous, and volume-controlled intermittent mandatory ventilation (VC-IMV) breaths are volume limited and volume cycled. 25. If lung compliance decreases while a patient is receiving mechanical ventilation with
pressure-controlled continuous mandatory ventilation (PC-CMV), which of the following would occur? a. Peak pressure increases. b. Peak pressure decreases. c. Tidal volume increases. d. Tidal volume decreases. ANS: D
Reduced compliance results in lower volumes during pressure-controlled continuous mandatory ventilation (PC-CMV). 26. A patient arrives in the emergency department following a motor vehicle accident in which the
patient sustained a deceleration chest injury. The patient was intubated in the field for airway protection. Physical assessment reveals that the patient is spontaneously breathing at a rate of 16 breaths/min, and breath sounds reveal bibasilar fine crackles at end-inspiration. A second arterial blood gas was drawn while the patient was receiving 100% oxygen from an air entrainment large volume nebulizer. Parameter 9:35 PM 10:10 PM pH 7.53 7.50 PaCO2 (mm Hg) 27 30 PaO2 (mm Hg) 48 56 SaO2 (%) 90 91 HCO3 (mEq/L) 24 24 Supplemental oxygen Room air 100% Bland aerosol The most appropriate recommendation for this patient is which of the following? a. Continuous positive airway pressure (CPAP) with supplemental oxygen b. Pressure-controlled inverse ratio ventilation (PCIRV) with positive end-expiratory
pressure (PEEP) and sedation c. Volume-controlled continuous mandatory ventilation (VC-CMV) d. Airway pressure release ventilation (APRV) ANS: A
Both the assessment and blood gas results reveal that the patient is spontaneously breathing. However, it appears that the patient is suffering from “air hunger.” The blood gases reveal that the patient has refractory hypoxemia. With this information, the most appropriate recommendation would be to place the patient on continuous positive airway pressure (CPAP) with supplemental oxygen to improve the refractory hypoxemia by opening up atelectatic areas and maintaining them open. Since the patient is breathing spontaneously, mechanical ventilator breaths are not necessary. 27. A patient with acute respiratory distress syndrome (ARDS) has developed a pneumothorax
from elevating peak and plateau pressures. The patient is currently being ventilated in the volume-controlled continuous mandatory ventilation (VC-CMV) mode with a set rate of 12 breaths/min. However, the patient is triggering the ventilator at a rate of 25 breaths/min. The arterial blood gas reveals ventilator-induced hyperventilation with corrected hypoxemia. The most appropriate recommendation to manage this patient on the ventilator is which of the following? a. Sedate the patient. b. Decrease the set ventilator rate. c. Switch the mode to pressure-controlled intermittent mandatory ventilation (PCIMV). d. Switch the mode to pressure-controlled continuous mandatory ventilation (PCCMV). ANS: C
Switching to pressure-controlled ventilation will reduce the continued risk for alveolar overdistention, which has already caused a pneumothorax, by limiting the amount of positive pressure applied to the lung. Using the intermittent mandatory ventilation (IMV) mode will decrease the ability of the patient to cause ventilator-induced hyperventilation by triggering mandatory breaths. IMV, with a low ventilator rate setting, can very well reduce this patient’s respiratory alkalosis. Using pressure support with the pressure- controlled intermittent mandatory ventilation (PC-IMV) mode will decrease the WOB for the patient during spontaneous breaths. 28. A patient, who is nasally intubated, due to facial surgery, has been successful on her
spontaneous breathing trial. She currently has moderate hypoxemia, despite a fractional inspired oxygen (FIO2) of 40% and positive end-expiratory pressure (PEEP) of 5 cm H2O while on volume-controlled continuous mandatory ventilation (VC-CMV). The most appropriate ventilator mode for this patient is which of the following? a. Airway pressure release ventilation (APRV) b. Continuous positive airway pressure (CPAP) c. Pressure support ventilation (PSV) with positive end-expiratory pressure (PEEP) d. Intermittent mandatory ventilation (IMV) with pressure support ventilation (PSV) and positive end-expiratory pressure (PEEP) ANS: D
The patient is ready to wean and can be placed on intermittent mandatory ventilation (IMV) to allow some ventilator breaths but also allow the patient to breathe spontaneously. The pressure support will help to overcome the increased airway resistance of the small endotracheal tube, due to the nasal intubation. The positive end-expiratory pressure (PEEP) will maintain oxygenation and keep the alveoli open. 29. A dual control mode provides pressure-limited ventilation with volume delivery targeted for
every breath. If the desired volume is not met the ventilator will volume cycle. This describes which of the following ventilator modes? a. Airway pressure release ventilation (APRV) b. Pressure augmentation (Paug) c. MMV d. Pressure-regulated volume control (PRVC) ANS: B
The pressure augmentation mode is a dual control mode that provides pressure-limited ventilation with volume delivery targeted for every breath. Each breath is flow cycled when the target volume is reached. If the guaranteed volume is not achieved before flow drops to the set level, the ventilator maintains the flow at the set value until the volume is delivered, and at that point the ventilator volume cycles. Pressure-regulated volume control (PRVC) is similar in that it also targets pressure and guarantees volume; however, when the set volume is not achieved the ventilator will incrementally increase pressure to achieve the volume. 30. The ventilator mode that delivers pressure breaths that are patient or time triggered, volume
targeted, time cycled, and where the pressure is automatically adjusted to maintain delivery of the targeted volume is which of the following? a. Volume support ventilation (VSV) b. Pressure augmentation (Paug) c. MMV d. Pressure-regulated volume control (PRVC) ANS: D
Pressure-regulated volume control (PRVC) is a volume targeted, pressure control mode that delivers breaths that are patient or time triggered, volume targeted, and time cycled. During each breath delivery the ventilator measures the tidal volume delivered and compares it to the targeted tidal volume, set by the operator. If the volume delivered is less than the set tidal volume, the ventilator will increase pressure delivery progressively over several breaths until the targeted tidal volume and the delivered tidal volume are about equal. Pressure augmentation (Paug) is similar, but the method for reaching the targeted volume is different. If the tidal volume is not reached the flow will continue until the ventilator volume cycles. Volume support ventilation (VSV) is also similar to PRVC. However, there is no time trigger in this mode and every breath is flow cycled. MMV requires the operator to set minute ventilation that serves as the threshold for ventilatory support. The ventilator increases or decreases the amount of support by increasing the rate of pressure, based on whether the patient is able to maintain the set minute ventilation. 31. The ventilator mode where every breath is patient triggered, pressure targeted, and flow
cycled with a volume target is which of the following? a. Volume support ventilation (VSV) b. Pressure-regulated volume control (PRVC)
c. Airway pressure release ventilation (APRV) d. Pressure augmentation (Paug) ANS: A
The mode being described is basically pressure support with a volume target. This describes volume support ventilation (VSV). Pressure-regulated volume control (PRVC) is similar; however, the breaths can be either patient or time triggered. Pressure augmentation (Paug) is similar to VSV; however, not every breath is flow cycled. If the volume is not met during inspiration, the ventilator will change to volume cycle. Airway pressure release ventilation (APRV) is a dual mode of ventilation that allows spontaneous breathing at two levels of continuous positive airway pressure (CPAP), where pressure support can be added. 32. A leak around a patient’s ET tube cuff during pressure support ventilation (PSV) will cause
which of the following to occur? Volume cycle Time cycle Pressure cycle Flow cycle
a. b. c. d.
ANS: B
A leak around a cuff could cause a pressure support breath to never flow cycle. For this reason, most ventilators time cycle at a maximum inspiratory time of 1.5–2 s. 33. The ventilator mode where the optimal breathing frequency that the ventilator delivers is
determined by delivering a test breath to the patient is which of the following? Adaptive support ventilation (ASV) Pressure-regulated volume control (PRVC) Airway pressure release ventilation (APRV) Pressure augmentation (Paug)
a. b. c. d.
ANS: A
The optimal breathing frequency that the ventilator delivers is determined by delivering a test breath to the patient, which is used to estimate the expiratory time constant for the patient’s respiratory system. This expiratory time constant is used along with the estimated dead space volume and the calculated minute ventilation to calculate the optimal breath frequency delivered by the ventilator. The optimal tidal volume can then be calculated by dividing the patient’s calculated minute ventilation by the optimal breathing frequency.
Chapter 06: Initial Ventilator Settings Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Calculate the average tidal volume for a patient who has a minute ventilation of 10 L/min with
a respiratory rate (RR) of 12 breaths/min. 120 mL 833 mL 1000 mL 1200 mL
a. b. c. d.
ANS: B
Minute ventilation equals respiratory rate multiplied by tidal volume (VT). Therefore, tidal volume equals minute ventilation divided by respiratory rate. 2. Calculate the inspiratory time (TI) when a ventilator is set at a tidal volume (VT) of 800 mL
and a constant flow rate of 40 L/min. 0.02 s 0.5 s 1.2 s 3.2 s
a. b. c. d.
ANS: C
. 3. Calculate the inspiratory time (TI) when a ventilator is set at a tidal volume (VT) of 500 mL
and a constant flow rate of 30 L/min. a. 0.6 s b. 1 s c. 1.5 s d. 1.7 s ANS: B
. 4. Calculate the inspiratory to expiratory (I:E) ratio for a ventilator that is set to deliver 850 mL
at a frequency of 15 breaths/min with a flow rate of 45 L/min. a. 1:1.1 b. 1:2.5 c. 1:3.5 d. 1:4 ANS: B
Minute ventilation equals respiratory rate multiplied by tidal volume. 5. Calculate the inspiratory to expiratory (I:E) ratio when the inspiratory time is 0.5 s and the
respiratory rate is 30 breaths/min. a. 1:3
b. 1:4 c. 4:1 d. 3:1 ANS: A
. 6. Calculate the expiratory time (TE) when the ventilator frequency is set to 25 breaths/min and
the inspiratory time (TI) is 0.75 s. 0.75 s 1.16 s 1.65 s 2.4 s
a. b. c. d.
ANS: C
7. What is the flow rate necessary to deliver a tidal volume (VT) of 600 mL, with a constant
waveform, at a respiratory rate of 15 breaths/min with an I:E of 1:4? 36 L/min 40 L/min 45 L/min 60 L/min
a. b. c. d.
ANS: C
8. Setting flow rates high will cause which of the following to occur? a. Improve gas exchange b. Lengthen inspiratory time c. Increase air trapping d. Increase peak pressures ANS: D
The flow setting on a mechanical ventilator determines how fast the inspired gas will be delivered to the patient. During continuous mandatory ventilation (CMV), high flows shorten inspiratory time (TI) and may result in higher peak pressures and poor gas distribution. 9. Slow flow rates will cause which of the following to occur? a. Poor gas exchange b. Increase peak pressures c. Shorten expiratory time d. Decrease mean airway pressure ANS: C
Slower flows may reduce peak pressures, improve gas distribution, and increase at the expense of increasing inspiratory time (TI). Unfortunately, shorter expiratory time (TE) can lead to air trapping, while using a longer TI may cause cardiovascular side effects. 10. The flow waveform pattern that provides the shortest inspiratory time (TI) of all the available
flow patterns with an equivalent peak flow rate setting is which of the following? a. Sine
b. Constant c. Ascending ramp d. Descending ramp ANS: B
Generally, a constant flow pattern provides the shortest inspiratory time (TI) of all the available flow patterns with an equivalent peak flow rate setting. 11. The flow waveform pattern that is created during pressure targeted ventilation is which of the
following? a. Sine b. Constant c. Ascending ramp d. Descending ramp ANS: D
The descending waveform occurs naturally in pressure ventilation. 12. The flow waveform pattern that will decrease peak pressure but at the same time may increase
mean airway pressure is which of the following? Sine Rectangular Ascending ramp Descending ramp
a. b. c. d.
ANS: D
In situations where plateau pressure (PPlat) is critical, changing to a descending ramp in order to reduce peak pressures may increase the mean airway pressure. 13. A patient having an acute, severe asthma exacerbation is intubated and set up on volume-
controlled continuous mandatory ventilation (VC-CMV). To ensure volume delivery at the lowest peak pressure while providing for better air distribution, which flow waveform should be used? a. Sine b. Constant c. Ascending ramp d. Descending ramp ANS: D
In patients with high airway resistance (Raw), the descending pattern is more likely to deliver a set tidal volume (VT) at a lower pressure and provide for better distribution of air through the lung than a constant or an accelerating flow. 14. The most appropriate tidal volume setting for a 6'3" male ventilator patient with normal lungs
is which of the following? 300 mL 500 mL 700 mL 900 mL
a. b. c. d.
ANS: B
First calculate ideal body weight . Then using the range of 5–7 mL/kg IBW the tidal volume range for this patient is 445–623 mL. 15. A 5'10" male patient with normal lungs has been intubated and requires mechanical
ventilation with volume-controlled continuous mandatory ventilation (VC-CMV). The tidal volume and ventilator rate settings that should be recommended for this patient are which of the following? a. VT = 525 mL, rate = 14 breaths/min b. VT = 750 mL, rate = 12 breaths/min c. VT = 825 mL, rate = 10 breaths/min d. VT = 950 mL, rate = 8 breaths/min ANS: A
First calculate ideal body weight (IBW) for a male, which is . Then using the range of , the tidal volume range for this patient is . Minute ventilation is about 100 mL/kg IBW. Therefore, minute ventilation should be approximately 7.5 L/min. Dividing the calculated minute ventilation by the tidal volume range for this patient provides a range of rates for the tidal volumes: 14–20 breaths/min depending on the set volumes. The most appropriate volume and rate combination for this patient is . 16. A 5'2" female patient with normal lungs has been intubated and requires mechanical
ventilation with volume-controlled continuous mandatory ventilation (VC-CMV). The tidal volume (VT) and ventilator rate settings that should be recommended for this patient are which of the following? a. VT = 315 mL, rate = 20 breaths/min b. VT = 364 mL, rate = 14 breaths/min c. VT = 468 mL, rate = 12 breaths/min d. VT = 563 mL, rate = 10 breaths/min ANS: B
First calculate ideal body weight (IBW) for a female, which is . Then using the range of the tidal volume range for this patient is 260–364 mL. Minute ventilation is about 100 mL/kg IBW. Therefore, minute ventilation should be approximately 5.2 L/min. Then dividing the calculated minute ventilation by the tidal volume range for this patient provides a range of rates for the tidal volumes: 14–20 breaths/min depending on the set volumes. The most appropriate volume and rate combination for this patient is . 17. A 26-year-old, 6'6", 250 lb male patient, is still under the effects of anesthesia following knee
surgery. His body temperature is 37 C. He has no history of lung disease. The appropriate initial minute ventilation for this patient is which of the following? a. 8.9 L/min b. 9.7 L/min c. 11.4 L/min d. 13.6 L/min ANS: B
First calculate ideal body weight (IBW) for a male, using the formula . This patient’s IBW is 97 kg. Minute ventilation is about 100 mL/kg IBW, which would be 97,000 mL/min or 9.7 L/min. 18. A 47-year-old, 5'6", 112 lb female patient, is still under the effects of anesthesia following a
hysterectomy. Her body temperature is 37 C. She has no history of lung disease. The appropriate initial minute ventilation for this patient is which of the following? a. 5.1 L/min b. 6.1 L/min c. 11.2 L/min d. 13.5 L/min ANS: B
First calculate ideal body weight (IBW) for a female, using the formula . This patient’s IBW is 51 kg. Minute ventilation is about 100 mL/kg IBW, which would be 51,000 mL/min or 5.1 L/min. 19. A 39-year-old, 5'4", 138 lb female patient requires intubation and mechanical ventilation. Her
body temperature is 39 C. She has no history of lung disease. The appropriate initial minute ventilation for this patient is which of the following? a. 5.7 L/min b. 6.8 L/min c. 7.6 L/min d. 13.8 L/min ANS: B
First calculate ideal body weight (IBW) for a female, using the formula . This patient’s IBW is 57 kg. Minute ventilation is about 100 mL/kg IBW, which would be 57,000 mL/min or 5.7 L/min. VE would have to be increased by 10% for each degree above 37 C: a total increase of ; therefore, the new minute ventilation (VE) would be . 20. A patient has a body temperature of 40 C. How should the initial minute ventilation setting
be adjusted? a. Increase it by 15%. b. Decrease it by 18%. c. Decrease it by 25%. d. Increase it by 30%. ANS: D
Minute ventilation (VE) would have to be increased by 10% for each degree above 37 C. 21. The pattern that has been shown to improve the distribution of gas in the lungs for an
intubated patient on volume-controlled continuous mandatory ventilation (VC-CMV) is which of the following? a. Sine waveform b. Ascending ramp c. Descending ramp d. Square waveform ANS: C
Studies comparing the descending flow pattern with the constant flow pattern suggest that the descending flow pattern improves the distribution of gas in the lungs. 22. A 47-year-old, 6'1" male patient is admitted to the hospital due to trauma from a motor vehicle
accident. Forty-eight hours post admission, the patient is suffering from respiratory distress with severe hypoxemia and is intubated. A chest X-ray, done prior to intubation, reveals a ground glass appearance bilaterally. The physician requests the volume-controlled continuous mandatory ventilation (VC-CMV) mode for this patient. The initial settings for the ventilator should be which of the following? a. VT = 450 mL, rate = 18 breaths/min, PEEP = 8 cm H2O b. VT = 600 mL, rate = 10 breaths/min, PEEP = 5 cm H2O c. VT = 750 mL, rate = 15 breaths/min, PEEP = 10 cm H2O d. VT = 900 mL, rate = 12 breaths/min, PEEP = 5 cm H2O ANS: A
First calculate ideal body weight (IBW) for a male, using the formula 106 + 6(ht 60). This patient’s IBW is 84 kg. Minute ventilation is about 100 mL/kg IBW, which would be 8.4 L/min. Since the patient appears to have acute respiratory distress syndrome (ARDS) the tidal volume should be set to between 4 and 6 mL/kg. This would make the appropriate tidal volume range 336–504 mL. This eliminates all of the choices except “A.” Dividing the tidal volume range into 8.4 L/min gives the set rate range at 17–25 breaths/min. This also eliminates all but choice “A.” 23. A 65-year-old, 73-inch-tall, 195 lb male patient was admitted 2 days ago for renal failure. The
patient has a history of chronic obstructive pulmonary disease (COPD) and has a pulse of 122 breaths/min, BP 153/88, and temperature 37 C. The patient is intubated for acute-on-chronic respiratory failure with hypoxemia. The physician requests volume-controlled continuous mandatory ventilation (VC-CMV). The initial settings for the ventilator should be which of the following? a. VT = 700 mL, rate = 12 breaths/min, PEEP = 3 cm H2O b. VT = 900 mL, rate = 10 breaths/min, PEEP = 5 cm H2O c. VT = 450 mL, rate = 20 breaths/min, PEEP = 8 cm H2O d. VT = 800 mL, rate = 15 breaths/min, PEEP = 10 cm H2O ANS: A
First calculate ideal body weight (IBW) for a male, using the formula 106 + 6(ht 60). This patient’s IBW is 84 kg. Minute ventilation is about 100 mL/kg IBW, which would be 8.4 L/min. Since the patient has a history of chronic obstructive pulmonary disease (COPD), the tidal volume should be set to between 8 and 10 mL/kg with rates of between 8 and 12 breaths/min. This would make the appropriate tidal volume range 672–840 mL. This eliminates the two choices where the volume is outside of this range, leaving choices “A” and “D.” Choice “D” can be eliminated because the rate of 15 is outside the suggested rates for COPD patients. Rapid rates will lead to air trapping in patients with high airway resistance. 24. A 57-year-old, 5'3", 165 lb female patient arrives in the open heart unit following coronary
artery bypass surgery. The patient has a history of diabetes and no history of pulmonary disease. The most appropriate initial volume-controlled continuous mandatory ventilation (VC-CMV) settings are which of the following? a. VT = 220 mL, rate = 25 breaths/min, PEEP = 10 cm H2O b. VT = 360 mL, rate = 15 breaths/min, PEEP = 5 cm H2O
c. VT = 550 mL, rate = 12 breaths/min, PEEP = 12 cm H2O d. VT = 750 mL, rate = 10 breaths/min, PEEP = 8 cm H2O ANS: B
First calculate ideal body weight (IBW) for a female, using the formula . This patient’s IBW is 55 kg. Minute ventilation is about 100 mL/kg IBW, which would be 5.54 L/min. Since the patient is post-op, the tidal volume should be set to between 5 and 8 mL/kg with rates of between 10 and 20 breaths/min. This would make the appropriate tidal volume range 275–440 mL. This fact eliminates choices “A,” “C,” and “D.” The positive endexpiratory pressure (PEEP) may also be too high for a post-op open heart patient in choices “A,” “C,” and “D.” 25. With which flow waveform pattern will the mean airway pressure be the highest? a. Sine b. Square c. Ascending ramp d. Descending ramp ANS: D
The descending ramp flow pattern keeps mean airway pressure high and may improve gas distribution. 26. A mechanically ventilated patient is going to be placed on pressure support ventilation
following an acceptable spontaneous weaning trial. The patient is a 5'9" male who weighs 185 lb. During volume-controlled continuous mandatory ventilation (VC-CMV) his average peak inspiratory pressure (PIP) was about 26 cm H2O and the plateau pressure (PPlat) was 16 cm H2O. What initial pressure support level should be set? a. 5 cm H2O b. 10 cm H2O c. 15 cm H2O d. 20 cm H2O ANS: B
The easiest way to establish the initial setting for pressure support ventilation (PSV) is to set it equal to the transairway pressure
.
27. An intubated patient with chronic obstructive pulmonary disease (COPD) is breathing on
pressure support ventilation (PSV) 13 cm H2O with positive end-expiratory pressure (PEEP) 5 cm H2O and a flow cycle setting of 25%. The pressure–time scalar shown in the figure is evaluated by the respiratory therapist. What action should the respiratory therapist take at this time?
a. b. c. d.
The patient and ventilator are synchronized and no change should be made. The inspiratory flow rate should be increased to match the patient’s needs. The flow cycle setting should be increased to allow more time for exhalation. The pressure support setting should be increased to match the peak pressure.
ANS: C
The slight rise at the end of inspiration on the pressure–time scalar in the figure shows that the patient is actively exhaling before the flow-cycle criterion is being met. This problem can be avoided by using a higher flow-cycle criterion that will end-inspiration sooner and allow for longer expiratory time to decrease air trapping. 28. When changing the control variable from volume control (VC) to pressure control (PC), the
initial inspiratory pressure should be set based on which of the following methods? Body surface area multiplied by 4 Plateau pressure measurement taken during VC ventilation Maximum peak inspiratory pressure during VC ventilation Maximum peak inspiratory pressure minus plateau pressure during VC ventilation
a. b. c. d.
ANS: B
Initial pressure is set at the plateau pressure (Pplat) value during volume-controlled continuous mandatory ventilation (VC-CMV) and must be adjusted as necessary to achieve tidal volume (VT). 29. A 63-year-old, 5'11", 185 lb male patient with a history of chronic obstructive pulmonary
disease (COPD) is admitted to the hospital due to liver failure. Over the course of the 48 hours he has developed respiratory distress. The respiratory therapist performs a physical assessment and finds the following: heart rate 135 beats/min, respiratory rate 28 with accessory muscle use. Breath sounds are decreased bilaterally with coarse crackles in the right base. A chest Xray from 24 hours ago shows bilateral lower lobe infiltrates. The patient has a nonproductive cough. The respiratory therapist draws an arterial blood gas that reveals: pH 7.31; partial pressure of carbon dioxide (PaCO2) 57 mm Hg; partial pressure of oxygen (PaO2) 58 mm Hg; arterial oxygen saturation (SaO2) 87%; bicarbonate (HCO ) 27 mEq/L while receiving oxygen via nasal cannula 3 L/min. The respiratory therapist should recommend which of the following for this patient? a. Continue with current therapy and monitor the patient closely. b. Place the patient on a nonrebreather mask with 15 L/min oxygen. c. Intubate and place on pressure-controlled continuous mandatory ventilation (PCCMV), peak inspiratory pressure (PIP) 40 cm H2O, positive end-expiratory pressure (PEEP) 8 cm water (H2O), fractional inspired oxygen (FIO2) 1.0. d. Use BiPAP with IPAP 10 cm H2O, EPAP 5 cm H2O, and bleed in 4 L/min oxygen. ANS: D
This patient is showing signs of ventilatory failure as evidenced by his acute-on-chronic respiratory acidosis with uncorrected hypoxemia. This patient should be tried on noninvasive positive pressure ventilation (NPPV) prior to intubation to try to avoid it if possible. Using a nonrebreather mask would not address the patient’s ventilatory problem and may cause oxygen-induced hypoventilation. Continuing with current therapy would not address the problem of impending ventilatory failure. If intubated and mechanically ventilated with pressure-controlled continuous mandatory ventilation (PC-CMV), starting off at 40 cm H2O is too high. When the peak inspiratory pressure (PIP) or plateau pressure (Pplat) from volume ventilation are not available, an initial pressure of 10–15 cm H2O should be set followed by volume measurements and pressure adjustments when appropriate. 30. The mode of ventilation that provides pressure-limited, time-cycled breaths that use a set tidal
volume as a feedback control is which of the following? a. Pressure support ventilation (PSV) b. Pressure-regulated volume control (PRVC) c. Pressure-controlled continuous mandatory ventilation (PC-CMV) d. Bilevel positive airway pressure (Bilevel PAP) ANS: B
Pressure support ventilation (PSV) is pressure-limited and flow-cycled. Pressure-regulated volume control (PRVC) is a dual control mode of ventilation that provides the benefits of pressure breathing along with targeting a set volume. These breaths are pressure-limited, timecycled, and use tidal volume as a feedback. The pressure is adjusted by the ventilator to meet the set volume. Pressure-controlled continuous mandatory ventilation (PC-CMV) is pressurelimited and time-cycled but does not have a volume feedback system. Bilevel PAP is similar to PC-CMV in that it is pressure-limited and time-cycled with no volume feedback. 31. The mode of pressure ventilation that is patient- or time-triggered and flow-cycled is which of
the following? Volume support (VS) Pressure support ventilation (PSV) Pressure-controlled continuous mandatory ventilation (PC-CMV) Bilevel positive airway pressure (bilevel PAP)
a. b. c. d.
ANS: D
Volume support (VS) and pressure support ventilation (PSV) are both patient-triggered and flow-cycled. Pressure-controlled continuous mandatory ventilation (PC-CMV) is patient- or time-triggered and time-cycled. Bilevel PAP is patient- or time-triggered and flow-cycled. 32. A patient receiving mechanical ventilation via pressure-regulated volume control (PRVC) has
a set target volume of 500 mL with an upper pressure limit setting of 35 cm H2O. During the respiratory therapist’s first patient-ventilator system check, 25 cm H2O was needed to deliver the set volume. Several hours later the pressure to deliver the set volume is 15 cm H2O. The respiratory therapist should do which of the following? a. Switch the patient to pressure support ventilation (PSV). b. No action should be taken. c. The set volume should be reduced. d. The upper pressure limit should be reduced. ANS: D
The upper pressure limit should be reduced so that the lungs are protected from pressures that would be too high for the recovering lungs. There is nothing in this scenario that gives any clues to the fact that the patient should be switched to PSV. Not taking any action in this situation could cause harm to the patient if the pressure were to rise suddenly, as with a cough or forcible exhalation.
Chapter 07: Final Considerations in Ventilator Setup Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. What fractional inspired oxygen (FIO2) setting should be set on the ventilator when the patient
currently has a partial pressure of oxygen (PaO2) of 53 mm Hg while receiving 50% oxygen and the desired PaO2 is 90 mm Hg? a. 0.64 b. 0.74 c. 0.85 d. 0.95 ANS: C
2. A patient’s baseline arterial blood gas (ABG) reveals a partial pressure of oxygen (PaO2) of 78
mm Hg while receiving 35% supplemental oxygen. What should the ventilator fractional inspired oxygen (FIO2) be set at to obtain a target PaO2 of 95 mm Hg? a. 0.34 b. 0.43 c. 0.55 d. 0.67 ANS: B
3. A patient receiving 60% oxygen from an air entrainment mask has a partial pressure of
oxygen (PaO2) of 45 mm Hg. The patient is being intubated and the ventilator set up. What is the appropriate fractional inspired oxygen (FIO2) to achieve a PaO2 of 60 mm Hg? a. 0.65 b. 0.75 c. 0.8 d. 0.95 ANS: C
4. The goal of selecting a specific oxygen concentration is to try to achieve clinically acceptable
arterial oxygen tensions within which of the following ranges? a. 40–55 mm Hg b. 50–60 mm Hg c. 60–100 mm Hg
d. 100–120 mm Hg ANS: C
The goal of selecting a specific fractional inspired oxygen (FIO2) for a patient is to achieve a clinically acceptable arterial oxygen tension (e.g., 60–100 mm Hg). 5. Following successful cardiac resuscitation, a patient being placed on mechanical ventilation
should have which of the following fractional inspired oxygen (FIO2) settings? a. 0.5 b. 0.6 c. 0.8 d. 1.0 ANS: D
Using a high oxygen concentration following a cardiac arrest can provide a way of restoring normal oxygenation and replacing tissue oxygen storage when oxygen debt and lactic acid accumulations occur, as with this patient. 6. What is the range for setting flow triggering? a. 1–10 L/min b. 10–15 L/min c. 12–16 L/min d. 20–30 L/min ANS: A
Flow triggering is set in a range of 1–10 L/min below the base flow depending on the selected ventilator. 7. A patient is intubated due to an acute exacerbation of chronic obstructive pulmonary disease
(COPD). The patient is now breathing with pressure support ventilation 5 cm H2O and continuous positive airway pressure (CPAP) 5 cm H2O. The patient is unable to flow trigger every inspiration. Unintended positive end-expiratory pressure (auto-PEEP) is measured at 10 cm H2O. The most appropriate action to take is which of the following? a. Decrease the CPAP to 3 cm H2O. b. Increase the CPAP to 8 cm H2O. c. Increase pressure support to 10 cm H2O. d. Change the flow trigger setting to 1 L/min. ANS: B
Patients may have trouble triggering a breath when unintended positive end-expiratory pressure (auto-PEEP) is present. When this occurs, adjusting the sensitivity may not alleviate the patient’s inability to trigger the ventilator. When auto-PEEP occurs in mechanically ventilated, spontaneously breathing patients with airflow obstruction, setting extrinsic PEEP to a level equal to about 80% of the patient’s auto-PEEP level may allow the ventilator to sense the patient’s inspiratory efforts. Decreasing the extrinsic PEEP level will not alleviate this problem. Altering the pressure support or the flow trigger will not alleviate this problem. 8. How much patient effort is needed to trigger a ventilator breath when there is 8 cm H2O of
unintended positive end-expiratory pressure (auto-PEEP) and a pressure trigger setting of 2 cm H2O? a. 2 cm H2O
b. 6 cm H2O c. 8 cm H2O d. 10 cm H2O ANS: D
The effort required to trigger a breath equals the sum of the auto-PEEP and the pressure trigger setting. 9. A humidifier used with a mechanical ventilator should deliver a minimum of how much
humidity? a. 10 mg H2O/L at 35–37 C b. 20 mg H2O/L at 31–35 C c. 30 mg H2O/L at 31–35 C d. 47 mg H2O/L at 35–37 C ANS: C
The humidification system used during mechanical ventilation should provide at least 30 mg H2O/L of absolute humidity at a range of about 31–35 C for all available flows up to 20–30 L/min. 10. Calculate the humidity deficit when a heat-moisture exchanger (HME) provided 14 mg/L of
water to the set tidal volume. 14 mg/L of water 23 mg/L of water 30 mg/L of water 37 mg/L of water
a. b. c. d.
ANS: C
11. In which situation should the heat-moisture exchanger (HME) be replaced with a heated
humidification system? With all tracheostomy tubes After 3 days of ventilation After 24 hours of ventilation Thick secretions not cleared by suctioning
a. b. c. d.
ANS: D
If secretions appear thick after two consecutive suctioning procedures, the heat-moisture exchanger (HME) should be removed and the patient switched to a heated humidification system. 12. Following intubation and placement on volume-controlled continuous mandatory ventilation
(VC-CMV), a patient’s average peak inspiratory pressure (PIP) is 26 cm H2O following suctioning. The appropriate settings for the low- and high-pressure alarms are which of the following? a. Low pressure = 6 cm H2O, high pressure = 46 cm H2O b. Low pressure = 15 cm H2O, high pressure = 41 cm H2O c. Low pressure = 20 cm H2O, high pressure = 36 cm H2O d. Low pressure = 24 cm H2O, high pressure = 31 cm H2O ANS: C
Low-pressure alarms are usually set about 5–10 cm H2O below peak inspiratory pressure (PIP). High-pressure alarms are set about 10 cm H2O above PIP. The only answer that fits both of these criteria is answer “C.” 13. A patient is being ventilated with pressure-controlled intermittent mandatory ventilation (PC-
IMV) of 12 breaths/min. The apnea alarm time setting should be which of the following? 4s 10 s 15 s 20 s
a. b. c. d.
ANS: B
Apnea alarms are usually set so the patient will not miss two consecutive machine breaths . The TCT would be 5 s/cycle (60 s/12 breaths/min = 5 s). Considering that the alarm should be activated after two missed mandatory breaths, then that would be 10 s or 2 TCT. 14. The ventilator volume is set at 575 mL. The low exhaled tidal volume (VT) alarm should be
set at which of the following? 150 mL 350 mL 400 mL 500 mL
a. b. c. d.
ANS: D
The low exhaled tidal volume (VT) alarm should be set at 10–15% below the set VT. 15. A patient set up on pressure support ventilation (PSV) has an average minute volume of 5.8 L.
What should the low exhaled minute volume alarm be set at? a. 5 L b. 4 L c. 3 L d. 2 L ANS: A
The low exhaled minute volume alarm should be set between 10% and 15% below the average minute volume. 16. The mechanical ventilator event that is considered potentially life-threatening or a level two
event is which of the following? a. Intrinsic positive end-expiratory pressure (PEEP) b. High respiratory rate c. Humidifier malfunction d. Exhalation valve failure ANS: C
Intrinsic PEEP = level 3; High respiratory rate = level 3; Humidification malfunction = level 2; Exhalation valve failure = level 1. 17. The respiratory therapist in the intensive care unit (ICU) responds to a patient’s room because
the ventilator is alarming. The most appropriate immediate action is which of the following?
a. b. c. d.
Replace the ventilator immediately. Silence the alarms and call for help. Ensure the patient is being ventilated. Troubleshoot the alarm settings.
ANS: C
When a ventilator alarm rings, the respiratory therapist (RT) must first ensure that the patient is being ventilated. If the RT doubts this, the patient should be disconnected from the ventilator and ventilated using a manual resuscitation bag. The RT should silence the alarms at that time and call for help. 18. Identify the patient who could benefit from sigh breaths. a. Patient on pressure-controlled continuous mandatory ventilation (PC-CMV) with
peak inspiratory pressure (PIP) = 38 cm H2O b. Patient on volume-controlled continuous mandatory ventilation (VC-CMV) with a
plateau pressure (Pplateau) = 36 cm H2O c. Spontaneously breathing patient receiving continuous positive airway pressure
(CPAP) d. 70 kg ideal body weight (IBW) patient on 400 mL with Pplateau = 25 cm H2O ANS: D
Mechanical ventilator sigh breaths are not recommended with higher tidal volumes or in the presence of plateau pressures . Sigh breaths may be harmful to spontaneously breathing patients receiving continuous positive airway pressure (CPAP) for the treatment of hypoxemia. Therefore, only the 70 kg ideal body weight (IBW) patient on 400 mL (5.7 mL/kg) with the plateau pressure of 25 cm H2O could benefit from sigh breaths. 19. All of the following are appropriate situations for the use of sigh or deep breaths except
which? During chest physiotherapy During an extubation procedure During continuous positive airway pressure (CPAP) with spontaneous breathing Before and after endotracheal tube suctioning
a. b. c. d.
ANS: C
Sigh breaths may be harmful to spontaneously breathing patients receiving continuous positive airway pressure (CPAP) for the treatment of hypoxemia. Sigh breaths are appropriate during chest physical therapy (CPT), extubation, and before and after suctioning. 20. How much pressure and time is necessary during a lung recruitment maneuver? a. 20–35 cm H2O for 30–40 s b. 30–40 cm H2O for 15–25 s c. 35–45 cm H2O for 40–60 s d. 40–50 cm H2O for 35–45 s ANS: C
The recruitment maneuver used to expand collapsed areas of the lung involves using a sustained high pressure of 35–45 cm H2O for 40–60 s.
21. Essential capabilities of an adult intensive care unit (ICU) ventilator include all of the
following except: expiratory pause. pressure control modes. flow rates up to 250 L/min. respiratory rates up to 60 breaths/min.
a. b. c. d.
ANS: C
Flow rates up to 180 L/min are suggested for adult ICU ventilators. Expiratory pause is used to measure intrinsic positive end-expiratory pressure (PEEP). The pressure control modes are essential for the ventilation of patients with low lung compliance. Respiratory rates of between 1 and 6 breaths/min are essential. 22. A 70-year-old, 61-inch-tall female patient was admitted with an acute exacerbation of chronic
obstructive pulmonary disease (COPD). After 12 hours of oxygen therapy, bronchodilator therapy, and intravenous corticosteroids, the patient began to show signs of clinical deterioration. Her chest X-ray revealed an enlarged heart and bilateral infiltrates. Her arterial blood gas shows acute on chronic respiratory failure. It is decided that this patient requires intubation and mechanical ventilation. The most appropriate ventilator settings for this patient include which of the following? a. Volume-controlled continuous mandatory ventilation (VC-CMV) rate 15, VT 200 mL, FIO2 1.0, positive end-expiratory pressure (PEEP) 5 cm H2O b. VC-CMV rate 12, VT 400 mL, FIO2 0.4, PEEP 3 cm H2O c. Pressure-controlled intermittent mandatory ventilation (PC-IMV) rate 10, peak inspiratory pressure (PIP) 30 cm H2O, FIO2 0.60, PEEP 3 cm H2O d. PC-IMV rate 12, PIP 35 cm H2O, FIO2 0.30, PEEP 8 cm H2O ANS: B
The tidal volume setting for patients with chronic obstructive pulmonary disease (COPD) should be 5–8 mL/kg with a rate of 8–16 breaths/min. Positive end-expiratory pressure (PEEP) should be less than or equal to 5 cm H2O. The ideal body weight (IBW) for this patient is 50 kg. Therefore, her tidal volume (VT) setting should be between 250 and 400 mL. Fractional inspired oxygen (FIO2) should be <0.50 with a PEEP of 3–5 cm H2O. The only answer that fits these criteria is “B.” 23. Methods to minimize air trapping in mechanically ventilated patients include which of the
following? a. Using a longer inspiratory time (TI) b. Switching to pressure support ventilation (PSV) c. Increasing inspiratory flow d. Administering a mucolytic agent ANS: C
To minimize air trapping, or intrinsic positive end-expiratory pressure (PEEPI), the following steps may be taken: switch to pressure-controlled continuous mandatory ventilation (PCCMV) with a short inspiratory time (TI), use a lower tidal volume (VT), maintain a clear airway, administer bronchodilators for bronchospasm, and increase inspiratory flow to lengthen expiratory time (TE).
24. A chronic obstructive pulmonary disease (COPD) patient with an ideal body weight of 65 kg
is brought to the emergency department. The patient is short of breath and using accessory muscles. Aerosolized bronchodilators are administered. The arterial blood gas reveals the following: pH 7.31, partial pressure of carbon dioxide (PaCO2) 72 mm Hg, partial pressure of oxygen (PaO2) 88 mm Hg, oxygen saturation (SaO2) 90%, bicarbonate (HCO ) 32 mEq/L on nasal cannula 2 L/min. The respiratory therapist should recommend which of the following at this time? a. Intubate volume-controlled continuous mandatory ventilation (VC-CMV) rate 15 breaths/min, tidal volume (VT) 650 mL, fractional inspired oxygen (FIO2) 0.50, positive end-expiratory pressure (PEEP) 6 cm H2O. b. Noninvasive positive pressure ventilation (NIV) with bilevel positive airway pressure (bilevel PAP) rate 8 breaths/min, inspiratory positive airway pressure (IPAP) 10 cm H2O, expiratory positive airway pressure (EPAP) 4 cm H2O. c. Intubate pressure-controlled intermittent mandatory ventilation (PC-IMV) rate 10 breaths/min, peak inspiratory pressure (PIP) 30 cm H2O, FIO2 0.60, PEEP 3 cm H2O. d. Administer 30% oxygen via air entrainment mask and continuous bronchodilator therapy. ANS: B
Unless critical emergency, an initial attempt with noninvasive ventilation should be tried using inspiratory positive airway pressure (IPAP) 10–12 cm H2O and expiratory positive airway pressure (EPAP) 3–5 cm H2O. 25. Sigh breaths could be beneficial during which of the following situations? a. Continuous positive airway pressure (CPAP) used for the treatment of hypoxemia b. Mechanical ventilation with c. Ventilating acute respiratory distress syndrome (ARDS) patient with plateau
pressure d. Pressure supported ventilation with tidal volume ANS: D
Sigh breaths are not indicated for patients on continuous positive airway pressure (CPAP) for hypoxemia because it may be harmful. Sighs are not recommended for patients being ventilated with tidal volumes >7 mL/kg or in the presence of plateau pressures >30 cm H2O. Sighs may be beneficial to patients who are receiving pressure supported ventilation and who have low tidal volumes with mild hypoxemia. 26. A 45-year-old, 73-inch-tall, 200 lb male patient is admitted to the emergency department with
an exacerbation of myasthenia gravis. The respiratory therapist assesses the patient and finds the patient’s maximum inspiratory pressure is 15 cm H2O and his vital capacity is 1200 mL. It is decided that the patient requires ventilatory support. The most appropriate ventilator settings for this patient are which of the following? a. Pressure support ventilation (PSV) 5 cm H2O, continuous positive airway pressure (CPAP) 10 cm H2O, FIO2 0.50 b. Pressure-controlled continuous mandatory ventilation (PC-CMV), f = 16 breaths/min, peak inspiratory pressure (PIP) = 35 cm H2O, positive end-expiratory pressure (PEEP) 3 cm H2O, fractional inspired oxygen (FIO2) 0.45 c. Noninvasive positive pressure ventilation—bilevel positive airway pressure (NIV
—BiPAP), f = 14 breaths/min, inspiratory positive airway pressure (IPAP) = 28 cm H2O, expiratory positive airway pressure (EPAP) = 5 cm H2O, FIO2 0.30 d. Volume-controlled intermittent mandatory ventilation (VC-IMV), f = 12 breaths/min, tidal volume (VT) = 725 mL, PSV 5 cm H2O, PEEP 5 cm H2O, FIO2 0.24 ANS: D
The patient is 73 inches and weighs 200 lb. Thus, . The patient’s body surface area (BSA) is 2.16 m2. The estimated minute ventilation is . Using 7–10 mL/kg the set tidal volume should be between 617 and 880 mL. The positive end-expiratory pressure (PEEP) should be 5 cm H2O and the fractional inspired oxygen (FIO2) should be 21% or close to it unless there is hypoxemia. A frequency of 12 with a tidal volume (VT) of 725 gives a minute volume of 8.7 L. This will give the patient full ventilatory support. Pressure support ventilation (PSV) is not appropriate because the patient appears too weak to breathe spontaneously. Noninvasive positive pressure ventilation (NIV) is not appropriate because of the increased risk of aspiration. 27. A 36-year-old female patient with a history of asthma is admitted to the ICU from the
emergency department. Her respirations are 30, very labored, with accessory muscle use and bilateral inspiratory and expiratory wheezing. There is bilateral hyperresonance during chest percussion. A blood gas taken in the ICU after 1 hour of continuous aerosolized albuterol (15 mg) reveals: pH 7.38, partial pressure of carbon dioxide (PaCO2) 42 mm Hg, partial pressure of oxygen (PaO2) 53 mm Hg, oxygen saturation (SaO2) 88%, bicarbonate (HCO ) 25 mEq/L with nasal cannula 6 L/min. The patient is 5'5" and weighs 135 lb. The most appropriate action at this time is which of the following? a. Continue current therapy with 20 mg albuterol and reassess in 1 hour. b. Noninvasive positive pressure ventilation (NIV) with bilevel positive airway pressure (bilevel PAP), f = 12, inspiratory positive airway pressure (IPAP) 28 cm H2O, expiratory positive airway pressure (EPAP) 3 cm H2O, fractional inspired oxygen (FIO2) 0.30 c. Intubate, use pressure-controlled continuous mandatory ventilation (PC-CMV), f = 8, peak inspiratory pressure (PIP) 28 cm H2O, TI 0.75 s, positive end-expiratory pressure (PEEP) 3 cm H2O, FIO2 1.0 d. Intubate, use volume-controlled continuous mandatory ventilation (VC-CMV), f = 12, tidal volume (VT) 600 mL, PF 40 L/min, PEEP 5 cm H2O, FIO2 0.60 ANS: C
The assessment and arterial blood gases (ABG) for this patient reveal impending respiratory failure. This patient should be intubated and may possibly require sedation and paralysis, depending on the ability to ventilate with synchrony. Therefore, continuation of the current therapy is not appropriate. Noninvasive positive pressure ventilation (NIV) is not appropriate with asthma patients who are in respiratory failure and may be unable to provide airway protection. The settings for the volume-controlled continuous mandatory ventilation (VCCMV) are not appropriate because the tidal volume is set too high, the frequency too low, and the peak flow too low. This would not allow enough time for exhalation and may cause barotrauma. The pressure-controlled continuous mandatory ventilation (PC-CMV) mode will allow for more control over the pressures. The short expiratory time will allow time for exhalation that will decrease the likelihood of hyperexpansion of the lungs.
28. Patients with acute severe asthma requiring mechanical ventilation are difficult to manage
because of which of the following? Diaphragmatic paralysis Increased lung compliance Decreased airway resistance Uneven alveolar hyperexpansion
a. b. c. d.
ANS: D
Increased airway resistance from bronchospasm, increased secretions, and mucosal edema cause air trapping, which can cause uneven hyperexpansion of various lung units. This can cause rupture or compress other areas of the lungs leading to pneumothorax, pneumomediastinum, subcutaneous emphysema, and other forms of barotrauma. 29. During mechanical ventilation, a patient with a closed head injury develops the Cushing
response. This may be immediately managed by using which of the following? a. Pressure-controlled continuous mandatory ventilation (PC-CMV) with positive
end-expiratory pressure (PEEP) b. Sedation and paralysis c. Permissive hypercapnia d. Iatrogenic hyperventilation ANS: D
The Cushing response is the normal response to acute increases in intracranial pressure (ICP). This includes hypertension with bradycardia. Iatrogenic hyperventilation, although controversial, is recommended when there is acute uncontrolled increased ICP. The partial pressure of carbon dioxide in the arteries (PaCO2) should be maintained between 25 and 30 mm Hg or titrated to the ICP if it is being monitored. This is a temporary solution and should be gradually reversed within 24–48 hours, allowing acid–base balance to restore itself. The use of pressure-controlled continuous mandatory ventilation (PC-CMV) and positive endexpiratory pressure (PEEP) can increase ICP further. Sedation and paralysis should only be used in extreme cases when the ventilator and patient are asynchronous (usually with severe asthma). Permissive hypercapnia may result in further increases in ICP. 30. A male patient who is 5'10" and weighs 190 lb arrives at the hospital having suffered a closed
head injury in a motor vehicle accident. The patient is unconscious and a computer tomogram of the head reveals an intracranial bleed. The patient receives an intracranial pressure (ICP) monitor following neurosurgery. Initial ventilator settings should include which of the following? a. Volume-controlled continuous mandatory ventilation (VC-CMV), respiratory frequency (f) 15 breaths/min, tidal volume (VT) 750 mL, positive end-expiratory pressure (PEEP) 5 cm H2O, fractional inspired oxygen (FIO2) 1.0 b. Pressure-controlled continuous mandatory ventilation (PC-CMV), f 15 breaths/min, peak inspiratory pressure (PIP) 35 cm H2O, PEEP 10 cm H2O, FIO2 1.0 c. Volume-controlled intermittent mandatory ventilation (VC-IMV), f 6 breaths/min, VT 300 mL, pressure support (PS) 10 cm H2O, PEEP 5 cm H2O, FIO2 0.50 d. Pressure-controlled intermittent mandatory ventilation (PC-IMV), f 12 breaths/min, PIP 20 cm H2O, PS 10 cm H2O, PEEP 5 cm H2O, FIO2 0.40 ANS: A
The initial settings for a closed head injury patient include pressure-controlled (PC) or volume-controlled (VC) continuous mandatory ventilation (CMV), tidal volumes between 8 and 12 mL/kg, respiratory frequency (f) 15–20 breaths/min, positive end-expiratory pressure (PEEP) 0–5 cm H2O with caution and higher only if there is severe hypoxemia, and fractional inspired oxygen (FIO2) 1.0 to start and titrate to keep partial pressure of oxygen (PaO2) between 70 and 100 mm Hg. This eliminates both intermittent mandatory ventilation (IMV) choices. The PC-CMV choice has a peak inspiratory pressure (PIP) and PEEP that are too high for this type of patient because it would increase intracranial pressure (ICP). Choice “A” fits within the guideline for ventilation of the closed head injury patient. 31. An 18-year-old, 5'6", 125 lb female patient was admitted to the hospital 2 days ago for spinal
meningitis. She developed sepsis and suffered hypercapnic respiratory failure. The patient was intubated and placed on volume-controlled continuous mandatory ventilation (VC-CMV), respiratory frequency (f) 12 breaths/min, tidal volume (VT) 600 mL, positive end-expiratory pressure (PEEP) 5 cm H2O, fractional inspired oxygen (FIO2) 0.40. Twenty-four hours later, the patient’s oxygen requirements have dramatically increased and her lung compliance has dramatically dropped, while her chest X-ray showed development of bilateral fluffy infiltrates. The most appropriate actions to take include which of the following? a. Keep VT the same, increase f to 25 breaths/min, increase PEEP to 12 cm H2O. b. Decrease VT to 250 mL, increase f to 15 breaths/min, increase PEEP to 15 cm H2O. c. Increase VT to 550 mL, decrease f to 8 breaths/min, increase PEEP to 10 cm H2O. d. Decrease VT to 400 mL, decrease f to 8 breaths/min, decrease PEEP to 3 cm H2O. ANS: B
During the acute phase of the disease, adequate ventilation should be provided using a tidal volume (VT) in the range of 4–6 mL/kg while plateau pressure (Pplateau) is maintained at with rates of 15–25 breaths/min. For this patient the VT range should be between 244 and 488 mL with a rate between 15 and 25 breaths/min. Answer “B” fits into this guideline. 32. While initially ventilating a patient with acute respiratory distress syndrome (ARDS), the
extrinsic positive end-expiratory pressure (PEEPE) should be maintained using which of the following methods? a. 50% of intrinsic positive end-expiratory pressure (PEEPI) b. Open lung approach c. Offset intrinsic PEEP d. Minimize mean airway pressure. ANS: B
During the early phase of acute respiratory distress syndrome (ARDS), it is important to keep extrinsic positive end-expiratory pressure (PEEPE) high enough to at least exceed the inflection point on a slow or static pressure volume. It is generally accepted by clinicians that the deflation limb of a slow pressure–volume loop best approximates the end-expiratory pressure range required to prevent alveolar collapse. Maintaining PEEPE above this pressure range helps to prevent opening and closing of small airways and alveoli. This is referred to as the open lung approach to ventilatory management. 33. The statement that is true concerning the use of permissive hypercapnia in the management of
patients with acute respiratory distress syndrome (ARDS) includes which of the following? a. The pH may be allowed to drop as low as 7.1.
b. Tromethamine (THAM) may be used to keep the pH above 7.2. c. Partial pressure of carbon dioxide (PaCO2) needs to rise rapidly to achieve success. d. PaCO2 should not be allowed to rise above 60 mm Hg. ANS: B
Acceptable endpoints for the management of acute respiratory distress syndrome (ARDS) based on arterial blood gases (ABGs) are partial pressure of carbon dioxide . Note that these values may vary among institutions. Some physicians prefer to use tromethamine (THAM) or sodium bicarbonate when pH drops below 7.20. 34. The application of positive pressure for patients with left ventricular failure is beneficial
because of which of the following? Increases venous return Decreases preload to the heart Increases afterload to the heart Improves perfusion to the myocardium
a. b. c. d.
ANS: B
The use of positive pressure in patients with left ventricular failure will reduce venous return and therefore reduce preload to the left ventricle. 35. A 72-year-old male patient (height 6'2", weight 95 kg) with a history of congestive heart
failure (CHF) presents to the emergency department complaining of shortness of breath and inability to lie down to sleep. Physical assessment reveals a very anxious patient with a pulse of 140, respirations 32, and labored with diaphoresis. Breath sounds are decreased with bibasilar coarse crackles. The patient has a productive cough of pink frothy secretions. The patient is placed on a nonrebreather mask and the resulting arterial blood gases (ABG) show: pH 7.25, partial pressure of carbon dioxide (PaCO2) 55 mm Hg, partial pressure of oxygen (PaO2) 54 mm Hg, oxygen saturation (SaO2) 86%, bicarbonate (HCO ) 24 mEq/L. The most appropriate immediate action to take includes which of the following? a. Face mask continuous positive airway pressure (CPAP) 10 cm H2O b. Intubate, volume-controlled continuous mandatory ventilation (VC-CMV), respiratory frequency (f) 20, tidal volume (VT) 810 mL, positive end-expiratory pressure (PEEP) 8 cm H2O, fractional inspired oxygen (FIO2) 1.0 c. Intubate, volume-controlled intermittent mandatory ventilation (VC-IMV), f 6, VT 425 mL, PEEP 10 cm H2O, FIO2 0.80 d. Noninvasive positive pressure ventilation (NIV) with bilevel positive airway pressure (bilevel PAP), inspiratory positive airway pressure (IPAP) 15 cm H2O, expiratory positive airway pressure (EPAP) 5 cm H2O, FIO2 0.60 ANS: D
The patient is suffering from cardiogenic pulmonary edema from congestive heart failure (CHF) and has both hypercapnic and hypoxemic respiratory failure. The use of noninvasive positive pressure ventilation (NIV) with bilevel positive airway pressure (bilevel PAP) while waiting for pharmacological treatment to take effect would be appropriate. Face mask continuous positive airway pressure (CPAP) may not provide enough support to allow the patient to reduce the partial pressure of carbon dioxide (PaCO2). Although intubation is a more aggressive alternative, the choices provided are not within the guidelines for ventilation of patients with CHF. These guidelines include a tidal volume (VT) between 8 and 12 mL/kg. That would be between 405 and 648 mL. This eliminates the answer with 810 mL tidal volume. The fractional inspired oxygen (FIO2) initially should be 1.0; this eliminates the choice with 0.80. 36. A high pressure ventilator alarm is sounding and you are unsure if ventilation is occurring.
What action should you take first? Hit the alarm silent button. Increase the oxygen concentration to 100%. Manually ventilate the patient. Increase the peak pressure alarm.
a. b. c. d.
ANS: C
When a ventilator malfunctions during use, the clinician must first ensure that the patient is being ventilated. When in doubt, the clinician should disconnect the patient from the ventilator, start manual ventilation using a manual resuscitation bag, silence the alarms, and call for help.
Chapter 08: Initial Patient Assessment Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The first step in the assessment and documentation of patient–ventilator interaction following
placement of a patient on a mechanical ventilator is which of the following? Verifying physician’s orders Verifying a passing operational verification procedure Checking the integrity of the ventilator circuit and the humidifier system Assessment of the patient’s vital signs, breath sounds, and level of consciousness
a. b. c. d.
ANS: A
The first step in the process of assessment and documentation of patient–ventilator interaction after a patient has been placed on a mechanical ventilator involves the respiratory therapist verifying the physician’s orders. The second step is to verify that the ventilator passed an operational verification procedure (OVP). The OVP involves checking the integrity of the ventilator circuit and the humidification system. The patient assessment is performed during the patient–ventilator system check. 2. The operational verification procedure (OVP) involves checking the ventilator circuit for
leaks. Ventilator settings that could be used to perform this procedure include which of the following? a. Tidal volume (VT) = 500 mL, Flow rate = 60 L/min, High pressure limit = 50 cm H2O b. VT = 1000 mL, Flow rate = 20 L/min, High pressure limit = maximum c. VT = 500 mL, Flow rate = 20 L/min, High pressure limit = maximum, Inspiratory pause = 2 s d. VT = 200 mL, Flow rate = Maximum, High pressure limit = 50 cm H2O, Inspiratory pause = 1 s ANS: C
To check for leaks in the ventilator circuit the operator should set the tidal volume to 500 mL, the gas flow low (e.g., 20 L/min), the maximum pressure limit high (e.g., 100–120 cm H2O), and an inspiratory pause of 1–2 s. 3. How often should the fractional inspired oxygen (FIO2) of an adult be measured? a. Twice daily b. Continuously c. Every patient-ventilator system check d. Every other patient-ventilator system check ANS: C
The fractional inspired oxygen (FIO2) for a ventilated adult should be measured during each patient-ventilator system check. Most ICU ventilators have oxygen analyzers that provide continuous monitoring of FIO2. 4. How long after beginning mechanical ventilation on a patient should an arterial blood gas
sample be drawn?
a. b. c. d.
5 minutes 10 minutes 15 minutes 20 minutes
ANS: C
An arterial blood gas sample should be obtained about 15 minutes following the initiation of mechanical ventilation. This is vital for the evaluation of the effectiveness of ventilation and oxygenation. 5. A female patient who is 5'7" tall and weighs 68 kg is being mechanically ventilated with
volume-controlled continuous mandatory ventilation (VC-CMV), set rate 12, patient trigger rate 25 breaths/min, tidal volume (VT) 500 mL, set flow rate 60 L/min, fractional inspired oxygen (FIO2) 40%, positive end-expiratory pressure (PEEP) 5 cm H2O. The patient is currently in distress using accessory muscles of inspiration. The respiratory therapist performs a patient-ventilator system check. The flow–time waveform shows a failure of the expiratory flow to return to zero before the next breath is triggered. The most appropriate action for the respiratory therapist to take includes which of the following? a. Sedate the patient. b. Switch to pressure-controlled continuous mandatory ventilation (PC-CMV). c. Decrease set rate to 8 breaths/min. d. Switch to volume-controlled intermittent mandatory ventilation (VC-IMV). ANS: D
There are two clues to the fact that this patient is having problems because of unintended positive end-expiratory pressure (auto-PEEP): the patient’s trigger rate of 25 breaths/min and the flow–time curve not returning to zero before the next breath is triggered. Sedating the patient is not the most appropriate action to take in this situation. Sedating and paralyzing the patient are reserved as last resorts for respiratory distress from patient-ventilator asynchrony. Switching to pressure-controlled continuous mandatory ventilation (PC-CMV) will most likely not change the situation too much, unless the pressure is markedly reduced to reduce the tidal volume. Decreasing the set rate to 8 breaths/min will not affect the patient’s trigger rate and therefore will not change the situation. Switching to a mode where there is more spontaneous breathing is an acceptable strategy for dealing with auto-PEEP. 6. Calculate the volume delivered to the patient when the tubing compliance (CT) is 2.5 mL/cm
H2O, the tidal volume (VT) at the exhalation port is 550 mL, and the peak inspiratory pressure (PIP) is 28 cm H2O. a. 70 mL b. 330 mL c. 480 mL d. 620 mL ANS: C
Volume lost = PIP CT and Delivered VT = Measured VT Volume lost 7. A 6'2" male patient is being ventilated in the volume-controlled continuous mandatory
ventilation (VC-CMV) mode with a set tidal volume (VT) of 650 mL. There is 40 mL of mechanical dead space. Calculate the final alveolar ventilation. a. 432 mL b. 445 mL
c. 510 mL d. 535 mL ANS: A
8. An increasing PIP may indicate which of the following? a. Decreasing lung compliance b. Decreasing airway resistance c. Leak in the ventilator circuit d. Increasing dynamic compliance ANS: A
Compliance is equal to tidal volume divided by peak inspiratory pressure (PIP). If the PIP is rising, the compliance is decreasing. Therefore, the answer is “A.” An increasing PIP would be caused by a rise in airway resistance and decreased dynamic compliance. A leak in the system would be indicated by a decreased PIP. 9. A pathophysiological condition that causes an increase in peak inspiratory pressure (PIP)
while transairway pressure (PTA) remains the same is which of the following? Acute respiratory distress syndrome (ARDS) Asthma Emphysema Chronic bronchitis
a. b. c. d.
ANS: A
An increase in peak inspiratory pressure (PIP) with a constant transairway pressure (PTA) is due to an increase in plateau pressure (Pplat). The most common reason for a rise in Pplat is acute respiratory distress syndrome (ARDS). The three other choices are all obstructive diseases that would cause an increase in the PTA with no significant change in Pplat. 10. During the course of several patient-ventilator system checks a respiratory therapist notices
that the patient’s peak inspiratory pressure (PIP) is rising, while the plateau pressure (Pplat) has remained the same. This most likely indicates which of the following? a. Decrease in dynamic compliance b. Increase in airway resistance c. Decrease in static compliance d. Increase in elastic recoil of alveolar walls ANS: B
The difference between the peak inspiratory pressure (PIP) and plateau pressure (Pplat) readings (PIP Pplat) is the transairway pressure (PTA). PTA is the amount of pressure required to overcome airway resistance (Raw) (Raw = PTA/Flow). Notice that PTA includes the resistance of the endotracheal tube (ET). A higher than expected difference between PIP and Pplat suggests an increased Raw. 11. The data on the following ventilator flow sheet for a patient being ventilated in the volume-
controlled continuous mandatory ventilation (VC-CMV) mode demonstrates which of the following? Time PIP (cm Pplat (cm H2O) PEEP (cm Exhaled VT Flow rate
0800 1000 1100 1130 a. b. c. d.
H2O) 35 39 45 50
30 34 39 44
H2O) 5 5 5 5
(mL) 1000 1000 1000 1000
(L/min) 60 60 60 60
Airway resistance is increasing. Lung compliance is decreasing. Dynamic compliance is increasing. Water is accumulating in the patient circuit.
ANS: B
This ventilator flow sheet shows that while the peak inspiratory pressure (PIP) and plateau pressure (Pplat) are both increasing over the course of the 3 hours, the transairway pressure has remained almost unchanged (either 5 cm H2O or 6 cm H2O). This means that there has been little change in airway resistance between 0800 and 1130. What is demonstrated is that there is an increase in the Pplat and that reflects an increase in the elastic resistance of the alveolar walls and thoracic cage against the volume being delivered. This is due to decreasing lung compliance or stiffening of the lungs. The other answers would cause an increase in the PTA. 12. A patient’s transairway pressure (PTA) is rising while the plateau pressure (Pplat) remains
unchanged. The treatment plan that could correct this problem includes which of the following? 1. Administer a bronchodilator. 2. Insert a chest tube. 3. Increase extrinsic positive end-expiratory pressure (PEEPE). 4. Suction airway secretions. a. 2 only b. 2 and 4 only c. 1 and 4 only d. 1 and 3 only ANS: C
An increase in the transairway pressure (PTA) reflects the need for an increased amount of pressure to overcome airway resistance (Raw). Raw most often increases when the patient’s airway needs suctioning, the patient is biting on the tube, the tube is kinked, or the patient has mucosal edema or bronchospasms (or both). Bronchospasm is treated with the administration of a bronchodilator, and retained airway secretions may be removed by suctioning. The presence of a pneumothorax requiring a chest tube would manifest an increase in plateau pressure (Pplat) along with other signs not present in this scenario. If the Pplat had been increased or if there was intrinsic positive end-expiratory pressure (PEEPI), increasing extrinsic positive end-expiratory pressure (PEEPE) might be a viable solution. 13. The respiratory therapist is evaluating the following ventilator flow sheet. The
recommendation that is most appropriate in this situation is which of the following? Time PIP (cm Pplat (cm PEEPE (cm Exhaled VT Flow rate H2O) H2O) H2O) (mL) (L/min) 0800 35 30 5 1000 60
1000 1100 1130 a. b. c. d.
39 45 50
34 39 44
5 5 5
1000 1000 1000
60 60 60
Increase extrinsic positive end-expiratory pressure (PEEPE). Suction the airway. Switch out the heat-moisture exchanger (HME). Administer a bronchodilator.
ANS: A
What is demonstrated here is that there is an increase in the plateau pressure (Pplat) and this reflects a decreasing lung compliance or stiffening of the lungs. Adding extrinsic positive endexpiratory pressure (PEEPE) to this patient could result in a decrease in the Pplat. Since the transairway pressure (PTA) has remained stable over the 3.5 hours, there is no increase in airway resistance and no need to suction the airway, switch out the heat-moisture exchanger (HME), or administer a bronchodilator. 14. Following initiation of volume-controlled continuous mandatory ventilation (VC-CMV)
ventilation, the patient’s average peak inspiratory pressure (PIP) is 23 cm H2O. The high pressure limit alarm should be set at which of the following? a. 28 cm H2O b. 33 cm H2O c. 38 cm H2O d. 43 cm H2O ANS: B
The high pressure limit alarm should be set to about 10 cm H2O. 15. Identify the plateau pressure (Pplat) for the pressure-controlled continuous mandatory
ventilation (PC-CMV) breaths in the figure.
a. Point A b. Point B
c. Point C d. Point D ANS: D
Point D occurs where there is no flow, as evidenced on the flow–time curve, and there has been some time for the ventilator pressure and lung pressure to equilibrate. 16. The volume–time curve is demonstrating which of the following?
a. b. c. d.
Auto-PEEP System leak Plateau pressure Volume triggering
ANS: B
The volume curve is not returning to zero. This means that there is a system leak somewhere in the patient-ventilator circuit that should be assessed. 17. The respiratory therapist observes the volume–time curve shown in the figure. What action
should the respiratory therapist take at this time?
a. b. c. d.
Add extrinsic positive end-expiratory pressure (PEEPE). Look for a system leak. Switch to flow triggering. Detach the ventilator and manually resuscitate.
ANS: D
The volume–time curve shows a leak in the system. Before beginning to troubleshoot to and find the location of the leak, the patient should be taken off the ventilator circuit and mechanically ventilated.
18. A 31-year-old woman is admitted to the emergency department following a motor vehicle
accident. The paramedics brought her into the ER in respiratory distress. She was intubated in the field and started on mechanical ventilation as soon as she arrived. Breath sounds were clear on the left and absent on the right. Percussion revealed resonance on the left and hyperresonance on the right. The patient’s trachea was shifted to the left. The most likely cause of this patient’s clinical presentation is which of the following? a. Acute respiratory distress syndrome (ARDS) b. Flail chest c. Pneumothorax d. Pleural effusion ANS: C
Absent breath sounds on the right side with hyperresonance means there is excessive air in the pleural cavity on the right side. A tracheal shift to the left indicates that there is either a rightsided pneumothorax or left-sided atelectasis. The presence of the hyperresonance with the tracheal shift and absent breath sounds points to the pneumothorax. 19. A 46-year-old male patient is 2 days post-op for surgery to repair an aortic aneurysm. He is
currently receiving mechanical ventilation. Auscultation of the anterior and posterior chest reveals bilateral late inspiratory crackles. Percussion is dull in both lower lobes. A STAT radiograph reveals bibasilar infiltrates. The most likely cause of this patient’s clinical presentation is which of the following? a. Asthma b. Pneumonia c. Pneumothorax d. Pleural effusion ANS: B
Late inspiratory crackles and infiltrates on the chest X-ray are indicative of consolidation due to pneumonia. A patient having an asthma exacerbation would present with wheezing, hyperresonance on percussion, and increased radiolucency on X-ray. A patient with a pneumothorax would have unilateral absence of breath sounds, hyperresonance on percussion over the affected area, and lack of vascular markings over the affected area on X-ray. A pleural effusion manifests itself on X-ray as a blunting of the costophrenic angle on the affected side, a pleural friction rub just above the fluid level, and dullness to percussion over the pleural effusion. 20. The respiratory therapist is performing a physical assessment of a patient receiving pressure
support ventilation. The patient is short of breath, has a respiratory rate of 28 breaths/min, a dull percussion note over the right base that becomes resonant over the right upper lobe, and resonance over the left lung. Chest movement on the right side is decreased. The STAT chest X-ray reveals a blunting of the right costophrenic angle. The pulmonary disorder that is causing this clinical presentation is which of the following? a. Acute respiratory distress syndrome (ARDS) b. Emphysema c. Pneumothorax d. Pleural effusion ANS: D
The dullness over the right base along with the resonance over the right upper lobe means that there is something either in or around the right lower lobe that is causing the dullness. The blunting of the right costophrenic angle along with the dull percussion over the right base points to a right-side pleural effusion. 21. To reduce the risk for tracheal damage associated with overinflated tube cuffs, cuff pressures
should not exceed what range of pressures? 10–15 mm Hg 15–20 mm Hg 20–25 mm Hg 25–30 mm Hg
a. b. c. d.
ANS: C
Intracuff pressures should not exceed
.
22. The respiratory therapist is monitoring the cuff pressure of a tracheostomy tube inserted in a
patient who is receiving mechanical ventilation. The cuff pressure is measured at 41 cm H2O. The respiratory therapist should immediately do which of the following? a. Inject more air through the pilot balloon. b. Release some of the air from the cuff. c. Insert a new tracheostomy tube. d. Do nothing; everything is acceptable. ANS: B
The endotracheal or tracheostomy cuff pressure is typically checked during the initial evaluation of the patient and once every 8–12 hours to ensure that cuff pressures do not exceed 20–25 mm Hg (27–34 cm H2O). It is generally accepted that maintaining the cuff pressure below 34 cm H2O (25 mm Hg) reduces the risk for tracheal damage associated with overinflated tube cuffs. 23. A 49-kg female patient intubated with a size 7 mm inner diameter (ID) endotracheal tube is
being mechanically ventilated in the volume-controlled continuous mandatory ventilation (VC-CMV) mode. During patient rounds, both the low-pressure and low-volume alarms are sounding persistently on the ventilator. Upon observation of the patient, the respiratory therapist hears murmuring from the patient, with audible sounds during inspiration. The cause of this condition is which of the following? a. Circuit leak b. Endotracheal tube (ET) cuff leak c. Circuit disconnection d. Incorrect ET tube size ANS: B
If a leak is present during a positive pressure breath, air can be heard escaping from the patient’s mouth. If there is a large enough leak, the ventilator’s low-pressure and low-volume alarms will sound. A circuit leak or disconnection would cause the low alarms to sound but not cause the leak around the endotracheal tube cuff. An incorrect endotracheal tube may cause a leak around the cuff. However, a size 7 mm ID is appropriate for this particular size patient.
24. An 87-kg male patient, orally intubated with a size 7.5 mm inner diameter (ID) endotracheal
tube, is being mechanically ventilated in the pressure-controlled continuous mandatory ventilation (PC-CMV) mode. During patient rounds, both the low-pressure and low-volume alarms are sounding persistently on the ventilator. Upon observation of the patient, the respiratory therapist hears murmuring from the patient, with audible sounds during inspiration. The respiratory therapist notes the position of the endotracheal tube is 21 cm at the gum line, measures the cuff pressure, and adds 3 mL of air to the cuff. To make an appropriate seal, it requires 44 cm H2O. The respiratory therapist should do which of the following? a. Change to a larger size endotracheal tube. b. Add air to the cuff and clamp the pilot tube. c. Check the position of the endotracheal tube. d. Reposition the endotracheal tube in the mouth. ANS: A
The endotracheal tube (ET tube) used with this patient is too small. This is evident from the fact that it is requiring 44 cm H2O to seal the airway and also because a size 7.5 mm ET tube should be used for a small adult female. This patient should have at least a size 8 mm ET tube. The placement of the tube is appropriate for the size, being 21 cm at the gum line, so repositioning is not necessary. Since the respiratory therapist has already added, measured, and noted that the airway can be sealed, but with a higher than normal pressure, we know that there is no problem with the pilot balloon. 25. How can the amount of cuff volume/pressure lost in the connecting tube be minimized during
cuff measurement using a three-way stopcock, a manometer, and a syringe? Using a four-way stopcock Overinflating the cuff prior to measurement Simultaneously inflating the cuff and manometer Pressurizing the manometer to 25 mm Hg prior to use
a. b. c. d.
ANS: D
Pressurizing the manometer to 25 mm Hg before measuring the cuff pressure will ensure that the pressure/volume in the cuff will not be lost into the connecting tubing. Once pressurized, the three-way stopcock, syringe, and manometer system can be inserted into the pilot. With all three ways open, the cuff can be inflated or deflated while the pressure is being measured. 26. The flow sheet below, for a patient on pressure-controlled continuous mandatory ventilation
(PC-CMV), demonstrates which of the following? Time PIP (cm H2O) PEEP (cm H2O) 0800 28 8 1000 28 8 1200 28 8 a. b. c. d.
Lung compliance is increasing. Dynamic compliance is decreasing. Airway resistance is decreasing. There is a leak in the ventilator circuit.
ANS: B
Exhaled VT (mL) 575 558 500
During pressure-controlled continuous mandatory ventilation (PC-CMV), a decrease in volume delivered is characteristic in a decreased dynamic compliance. If lung compliance increased or airway resistance decreased, the exhaled tidal volume would have increased. A leak in the ventilator circuit would also drop the peak inspiratory pressure (PIP). 27. The normal airway resistance range is which of the following? a. 0.6–2.4 cm H2O/(L/s) b. 16–24 cm H2O/(L/s) c. 26–34 cm H2O/(L/s) d. 70–100 cm H2O/(L/s) ANS: A
Normal Raw ranges from 0.6 to 2.4 cm H2O/(L/s). 28. A patient’s transairway pressure (PTA) is rising while the plateau pressure (Pplat) remains
unchanged. The treatment plan that could correct this problem includes which of the following? 1. Administer a bronchodilator. 2. Insert a chest tube. 3. Measure unintended positive end-expiratory pressure (auto-PEEP). 4. Suction airway secretions. a. 2 and 3 only b. 2 and 4 only c. 1 and 4 only d. 1, 2, and 3 only ANS: C
Airway resistance can be estimated for a ventilated patient using transairway pressure (PTA). When the PTA rises, the airway resistance is rising. When plateau pressure (P ) is constant, this means that the static compliance has not changed. In this question the PTA is rising while the P
remains the same. This is due to an increase in Raw and can be corrected by
administering a bronchodilator and/or suctioning the airways. An increase in P could occur from a pneumothorax, which would require the insertion of a chest tube and also from dynamic hyperinflation, which can be measured as unintended positive end-expiratory pressure (auto-PEEP). 29. Which of the following indicates an increase in airway resistance in a patient receiving
mechanical ventilation with a constant tidal volume? Increased peak inspiratory pressure (PIP) and transairway pressure (PTA) Increased static compliance Increased plateau pressure (Pplat) and stable PIP Decreased dynamic compliance
a. b. c. d.
ANS: A
Airway resistance can be estimated for a ventilated patient using transairway pressure (PTA). When peak inspiratory pressure (PIP) increases and plateau pressure (Pplat) remains relatively unchanged, there is an increase in PTA. An increased Pplat and a stable PIP indicate a decrease in static compliance.
30. The pressure at which large numbers of alveoli are recruited in a patient with acute respiratory
distress syndrome (ARDS) is located on the static pressure-volume curve at which of the following points? a. Upper inflection point b. Lower inflection point c. Peak inspiratory pressure d. Between the lower and upper inflection points ANS: B
The lower inflection point marks a significant change in the slope of the curve and may indicate the pressure at which large numbers of alveoli are recruited. 31. The pressure at which large numbers of alveoli become overinflated in a patient with acute
respiratory distress syndrome (ARDS) is located on the static pressure–volume curve at which of the following? a. Upper inflection point b. Lower inflection point c. Peak inspiratory pressure d. Between the lower and upper inflection points ANS: A
The upper inflection point indicates a point at which large numbers of alveoli are becoming overinflated. 32. The static pressure–volume curve shown in the figure indicates the presence of which of the
following?
a. b. c. d.
Atelectasis Pneumonia Pneumothorax Bronchospasm
ANS: D
The static compliance (CS) line shown in the figure is normal. However, the dynamic compliance (CD) curve shows that with increasing volumes there are very high pressure increases. This shows a right shift and flattening of the CD curve and is indicative of increasing airway resistance. Bronchospasm causes an increase in airway resistance. Atelectasis, pneumonia, and pneumothorax will cause both the CS and CD curves to shift right and flatten.
33. To help prevent inflated alveoli from collapsing and reexpanding with each breath, the
positive end-expiratory pressure (PEEP) level should be set at which point on the deflation part of the loop? a. Above the upper inflection point b. Below the upper inflection point c. Above the lower inflection point d. Below the lower inflection point ANS: C
Setting positive end-expiratory pressure (PEEP) above the lower inflection point on the deflation part of the loop may help prevent inflated alveoli from collapsing and reexpanding with each breath. 34. The flow sheet below, for a patient on pressure-controlled continuous mandatory ventilation
(PC-CMV), demonstrates which of the following? Time 0800 1000 1200 a. b. c. d.
PIP (cm H2O) 28 28 28
PEEP (cm H2O) 8 8 8
Exhaled VT (mL) 435 493 500
Overinflated endotracheal tube Lung compliance is decreasing. Airway resistance is decreasing. Dynamic compliance is worsening.
ANS: C
During pressure-controlled continuous mandatory ventilation (PC-CMV), increased tidal volume (VT) delivery with the same pressure indicates an improvement in compliance and/or a decrease in airway resistance (Raw). 35. The low-pressure and low-tidal volume alarms are sounding on a mechanically ventilated
patient. Measurement of the cuff pressure reveals 18 cm H2O. What action should be taken? Replace the endotracheal tube with a larger size. Add enough air to the cuff to maintain the cuff pressure at 34 cm H2O. Increase the set pressure to increase the tidal volume and compensate for the leak. Add air until a slight leak is heard while auscultating the larynx, then measure pressure.
a. b. c. d.
ANS: D
The minimum leak technique (MLT) should be used whenever possible to avoid tracheal necrosis associated with cuff overinflation. The size of the tube and patient is not given, so one cannot say whether or not the endotracheal (ET) tube is too small. 34 cm H2O is the maximum pressure that should be in a cuff. However, since all airways are different, the most effective way to minimize the risk for tracheal problems is to use MLT. 36. Before a ventilator is used, an operational verification check is performed. A simple variation
of this procedure is also performed under which of the following circumstances? a. Before a blood gas sample is obtained b. When the physician’s order specifies a change in ventilator settings c. Before a patient is reconnected to a ventilator after the ventilator circuit has been
changed or disassembled for any reason d. Before the patient’s hemodynamic status is monitored ANS: C
Options A, B, and D refer to times when a patient-ventilator system checks are performed. BOX 8-2 Simple Verification of Ventilator Operation
37. A physical examination of the chest is performed on a patient who is being mechanically
ventilated. Breath sounds and percussion are normal except over the right middle lobe, where late inspiratory crackles are heard. This area is dull to percussion. An evaluative chest radiograph image reveals infiltrates in the right middle lobe. Based on these findings alone, which of the following is the most likely problem? a. Pneumothorax in the right hemithorax b. Congestive heart failure c. Right middle lobe pneumonia d. Asthma affecting the right side only ANS: C
For patients with pneumonia, the chest is dull to percussion, breath sounds are decreased, and crackles occur late in inspiration over the affected area.
Chapter 09: Ventilator Graphics Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Identify the sinusoidal (or sine) waveform in the figure below.
a. b. c. d.
Figure A Figure B Figure C Figure D
ANS: C
The sinusoidal waveform looks very much like the first half of a mathematical sine wave. 2. The two waveforms that are common for pressure scalars are which of the following? a. Sinusoidal and ascending ramp b. Rectangular and exponential rise c. Descending ramp and ascending ramp d. Exponential decay and descending ramp ANS: B
Pressure waveforms are usually the rectangular or rising exponential type. 3. The most important factor to affect the degree of resistance in the airways is which of the
following? Flow rate of the gas Viscosity of the gas Length of the airways Diameter of the airways
a. b. c. d.
ANS: D
The most important factor affecting the degree of airway resistance is the diameter of the airways. The mathematical law that determines this fact is Poiseuille’s law. A large diameter airway will have low airway resistance and there will be a greater flow of gas. A small diameter airway will have high resistance and there will be a lower flow.
4. The peak inspiratory flow rate on the flow–time scalar below is which of the following?
a. b. c. d.
25 L/min 40 L/min 46 L/min 55 L/min
ANS: C
If you draw a line across the top of the square wave of the inspiratory flow scalar, the flow rate equals 46 L/min. 5. What is the inspiratory time shown in the flow–time scalar below?
a. b. c. d.
0.5 s 1s 1.5 s 2s
ANS: B
Inspiratory flow delivery stops at 1 s on this flow–time scalar. 6. What is the expiratory time shown in the flow–time scalar below?
a. b. c. d.
1s 1.5 s 2s 2.5 s
ANS: B
The first breath ends at 1 s and the second breath begins at 2.5 s. Therefore, the expiratory time is 2.5 s 1 or 1.5 s. 7. What is the trigger variable for the “A” breath shown in the figure below?
a. b. c. d.
Flow Time Pressure Volume
ANS: B
There is no patient trigger noted; therefore, the trigger in this case is time. 8. Calculate the static compliance using the information from the scalar below.
a. b. c. d.
10 mL/cm H2O 16 mL/cm H2O 20 mL/cm H2O 80 mL/cm H2O
ANS: C
The volume is 400 mL, the plateau pressure (PPlat) is 25 cm H2O, and the positive endexpiratory pressure (PEEP) is set at 5 cm H2O. Static compliance = volume returned/Pplat. 9. What is the inspiratory time for the ventilator breath shown in section B of the figure below?
a. b. c. d.
0.5 s 1.0 s 1.5 s 2.0 s
ANS: A
Inspiration in section B of the figure is approximately 0.5 s. This can be found by drawing a straight line through the beginning of the breath on all three of the scalars and a second line at the end of inspiration on each of the scalars as shown below:
10. Calculate the airway resistance (Raw) using the information from the scalar below.
a. 0.9 cm H2O/(L/s) b. 1.1 cm H2O/(L/s) c. 22.4 cm H2O/(L/s) d. 60 cm H2O/(L/s) ANS: C
Airway resistance (Raw) = Peak inspiratory pressure (PIP) Plateau pressure (Pplat)/flow (L/s). PIP = 40 cm H2O; Pplat = 25 cm H2O; flow = 40 L/min or 0.67 L/s; Raw = 15/0.67 = 22.4 cm H2O/(L/s).
11. The respiratory therapist observes the pressure–time scalar seen below. Wave A was generated
at 1300 hour and wave B at 1600 hour. The action that is most appropriate for this situation is which of the following?
a. b. c. d.
Add positive end-expiratory pressure (PEEP). Change the endotracheal tube (ET). Change to pressure-controlled continuous mandatory ventilation (PC-CMV). Administer a bronchodilator.
ANS: D
When comparing the two waveforms it should be noted that the plateau pressures (Pplat) are the same for both, 15 cm H2O. However, the peak inspiratory pressure (PIP) is higher in waveform B, 35 cm H2O, as opposed to waveform A, 27 mm H2O. This indicates an increase in transairway pressure (PTA) and therefore, airway resistance. The most appropriate answer is to administer a bronchodilator. If the ET tube was too small the PTA would have been consistently high from the start of mechanical ventilation. Adding PEEP or switching to pressure-controlled continuous mandatory ventilation (PC-CMV) would be appropriate if the Pplat was increasing. 12. The ventilator graphics generated by mechanical ventilation with pressure-controlled
continuous mandatory ventilation (PC-CMV), rate 18, peak inspiratory pressure (PIP) 25 cm H2O, positive end-expiratory pressure (PEEP) 5 cm H2O, are shown in the scalars below. Interpretation of these scalars reveals which of the following?
a. b. c. d.
The flow rate is set too high and should be reduced. There is air trapping that could be due to a high respiratory rate. The ventilator settings are appropriate and there are no problems. There is a leak in the system that needs to be identified and corrected.
ANS: B
Breaths are beginning prior to the patient completely exhaling. This is shown on the flow– time scalar by the expiratory flow not having enough time to return to zero before the next breath is delivered. It is possible that this is caused by the set rate of 18 breaths/min and/or by an increased airway resistance. One can also conclude that there is unintended positive endexpiratory pressure (auto-PEEP) preset in this situation. 13. Identify the improperly set ventilator parameter using the scalars shown below.
a. b. c. d.
Mode Flow rate Sensitivity Tidal volume
ANS: C
The breaths shown are both patient triggered. Negative deflections on the pressure–time scalar are present for both complete breaths shown. There is also a negative deflection between the two that did not result in a ventilator breath. A closer look at the amount of pressure required to trigger a ventilator breath shows that it is set too insensitive. In this situation the patient needs to generate a pressure of 10 cm H2O below the baseline to trigger a breath. The negative deflection in the center of the pressure–time scalar demonstrates that the patient could not generate enough negative pressure to trigger a breath. Therefore, the sensitivity is not set properly. 14. The respiratory therapist sees the following scalars on the screen of a ventilator providing
support to a patient in the ICU. What action should the respiratory therapist take?
a. Switch to the volume-controlled intermittent mandatory ventilation (VC-IMV)
mode. b. Increase the flow rate to 60 L/min. c. Decrease the sensitivity to 2 cm H2O. d. Increase the tidal volume to 550 mL. ANS: C
The breaths shown are both patient-triggered. Negative deflections on the pressure–time scalar are present for both complete breaths shown. There is also a negative deflection between the two that did not result in a ventilator breath. A closer look at the amount of pressure required to trigger a ventilator breath shows that it is set at 10 cm H2O. The negative deflection in the center of the pressure–time scalar demonstrates that the patient could not generate enough negative pressure to trigger a breath. Therefore, the sensitivity needs to be reduced to 2 cm H2O. 15. The volume curve on a volume–time scalar is consistently dropping below the baseline during
exhalation. The first action to take is which of the following? Measure the plateau pressure. Measure the endotracheal (ET) tube cuff pressure. Check the ventilator circuit for a leak. Assess the patient for active exhalation.
a. b. c. d.
ANS: D
When the volume drops below the baseline during exhalation, the cause could be active exhalation or an inspiratory time that is too long. Assessing the patient for active exhalation is the only viable answer given the choices. By doing the assessment the respiratory therapist can determine whether active exhalation is the cause. 16. A patient is receiving full ventilatory support with volume ventilation. At 0700 the respiratory
therapist observes the pressure–, volume–, and flow–time scalars shown in “A” below. Six hours later the respiratory therapist observes the scalars shown in “B.” The most appropriate action to take is which of the following?
a. b. c. d.
Increase the positive end-expiratory pressure (PEEP) level. Check the circuit for a leak. Administer a bronchodilator. Switch to pressure ventilation.
ANS: C
All three scalars show signs of increased airway resistance. The pressure–time scalar shows an increase in peak inspiratory pressure (PIP). The volume–time scalar shows that it is taking longer for the patient to exhale all the volume. The flow–time scalar shows that the expiratory flow is very slow and takes a long time to rise to the zero baseline. 17. An inadequate flow setting during volume ventilation will cause which of the following to
occur? The volume curve will drop below the zero baseline. The volume curve will not drop to the zero baseline. The exhaled flow will take longer to rise to the zero baseline. The pressure–time curve will appear concave during inspiration.
a. b. c. d.
ANS: D
When the flow rate setting is inadequate, the pressure–time scalar takes a concave shape during inspiration. A volume curve dropping below baseline is indicative of active exhalation. A volume curve that ends above baseline indicates a leak. An exhaled flow curve that takes the entire expiratory time to rise back to zero baseline is indicative of increased airway resistance. 18. The respiratory therapist observes the following pressure–time and flow–time scalars
following a patient being intubated and placed on a mechanical ventilator using volume ventilation. The most appropriate action is which of the following?
a. b. c. d.
Increase the set flow rate. Switch to pressure control. Increase the set tidal volume. Change to a decelerating flow pattern.
ANS: A
When the flow rate setting is inadequate, the pressure–time scalar takes on a concave shape during inspiration when the patient is actively inhaling. In this case the demand exceeds the ventilator setting and capability. The inspiratory demand of the patient will be provided for by increasing the set flow. 19. The type of flow curve produced by volume ventilation with constant flow is which of the
following? Sinusoidal Rectangular Descending ramp Exponential decay
a. b. c. d.
ANS: B
Volume ventilation with a constant flow will produce a rectangular flow curve unless a different flow pattern is chosen. Pressure ventilation creates a descending curve that varies with both lung characteristics and patient flow demand. 20. During pressure-controlled continuous mandatory ventilation (PC-CMV) the respiratory
therapist observes the pressure–time scalar shown below. The most appropriate action to take is which of the following?
a. b. c. d.
Adjust the inspiratory time. Increase the flow rate setting. Adjust the inspiratory rise time control. Increase the peak inspiratory pressure setting.
ANS: C
The pressure–time scalar shows a pressure spike at the beginning of the pressure curve before the pressure adjusts to the set value. Adjusting the inspiratory rise time control will slow the rate at which pressure and flow exit the ventilator. This will reduce or eliminate the pressure spike. 21. An increase in airway resistance during pressure ventilation will result in which of the
following? Plateau pressure (PPlat) will increase. Volume curve will resemble an igloo. Inspiration will end prior to flow tapering to zero. Pressure curve will become concave on inspiration.
a. b. c. d.
ANS: C
With increased airway resistance the flow–time scalar will show a curve that is flatter in appearance. Flow will not drop to zero by the time the set inspiratory time is reached. Consequently, the ventilator and lung pressures do not equilibrate and this can affect the overall volume delivered to the patient. 22. A reduction in compliance during pressure ventilation will cause which of the following? a. Delivered tidal volume will decrease. b. Volume curve will end under the zero line. c. Inspiration will end prior to flow tapering to zero. d. Pressure curve will become concave on inspiration. ANS: A
When compliance is reduced during pressure ventilation the volume delivered will be reduced proportionally. The volume curve ending under the zero line is indicative of active exhalation. Inspiration ending prior to the flow tapering to zero is consistent with an increase in airway resistance. The pressure curve becoming concave on inspiration is consistent with inadequate flow. 23. Delayed termination during pressure support ventilation (PSV) can be avoided with patients
who have chronic obstructive pulmonary disease (COPD) by doing which of the following? Increase inspiratory time Increase flow-cycle percent Change the flow pattern Decrease peak inspiratory pressure
a. b. c. d.
ANS: B
The presence of active exhalation during pressure support ventilation (PSV) indicates that the patient is trying to end the breath early. This is referred to as delayed termination and is associated with patient-ventilator asynchrony. This phenomenon is often seen with patients who have increased airway resistance, as in chronic obstructive pulmonary disease (COPD). Since inspiratory time is determined by flow cycling in PSV, increasing the flow-cycle setting will shorten inspiration, allowing more time for exhalation. 24. What is the flow-cycle setting for the pressure support ventilation (PSV) breaths shown in the
scalars below?
a. b. c. d.
10% 25% 40% 50%
ANS: D
The peak inspiratory flow is 40 L/min. Inspiration ends at 20 L/min. The flow cycle is therefore set at 50%. 25. Calculate the static compliance using the information from the pressure–volume loop below.
a. b. c. d.
15 mL/cm H2O 20 mL/cm H2O 25 mL/cm H2O 30 mL/cm H2O
ANS: D
The alveolar pressure is between 21 and 22 cm H2O and the set positive end-expiratory ventilation (PEEP) is 5 cm H2O. The tidal volume is 500 mL. 26. What is the cause of the change from pressure–volume loop A to pressure–volume loop B
during volume-controlled continuous mandatory ventilation (VC-CMV)?
a. b. c. d.
Decreased compliance Increased compliance Decreased airway resistance Increased airway resistance
ANS: A
The volume delivered remains the same for both the loops. However, the pressure has increased from approximately 20–35 cm H2O. The alveolar pressure (PA) has increased also. This is indicative of a decrease in compliance. 27. During a patient-ventilator system check the respiratory therapist notices that the pressure–
volume loop begins at zero on the x-axis but does not return to zero during expiration. The cause of this is which of the following? a. Active exhalation b. Inadequate sensitivity c. Ventilator circuit leak d. Decreased compliance ANS: C
When the loop on a pressure–volume loop does not return to zero during exhalation, there is a leak in the ventilator circuit. 28. Identify the type of flow waveform the ventilator is delivering from the flow–volume loop
below.
a. b. c. d.
Ascending ramp Rectangular Descending ramp Exponential decay
ANS: B
The inspiration is above the baseline and expiration is below the baseline in the flow–volume loop. The inspiratory flow pattern is rectangular. 29. A patient is receiving ventilation with volume-controlled continuous mandatory ventilation
(VC-CMV). During a patient-ventilator system check the respiratory therapist sees the flow– volume loop below. The most appropriate action is to do which of the following?
a. b. c. d.
Add positive end-expiratory pressure (PEEP). Switch to pressure-controlled continuous mandatory ventilation (PC-CMV). Administer a bronchodilator. Check the endotracheal (ET) tube cuff pressure.
ANS: C
The flow–volume loop shown in this question reflects increasing airway resistance. The expiratory flow part of the loop shows the scooped-out appearance. This is typical of a patient with airway obstruction. Administration of a bronchodilator will help to relieve some of the airway obstruction due to bronchospasm. Since the problem is obstructive and not restrictive, adding positive end-expiratory pressure (PEEP) or switching to pressure-controlled continuous mandatory ventilation (PC-CMV) will not address the issue. The flow–volume loop shows no leak in the system. 30. The type of breath shown in the flow–volume loop below is which of the following?
a. b. c. d.
Pressure support ventilation (PSV) Continuous positive airway pressure (CPAP) Pressure-controlled continuous mandatory ventilation (PC-CMV) Spontaneous without support
ANS: D
Part of the flow–volume curve occurs to the left of the y-axis; this reflects a drop in pressure during inspiration (pressure value becomes negative) and an increase in pressure with exhalation (pressure becomes positive). 31. Which of the following conditions causes a pressure–volume loop during volume-controlled
continuous mandatory ventilation (VC-CMV) to extend farther to the right and flatten out? Asthma Bronchitis Emphysema Pneumonia
a. b. c. d.
ANS: D
The extension to the right and flattening out of the pressure–volume loop during VC-CMV is indicative of decreasing compliance. This could be caused by pneumonia. Asthma, bronchitis, and emphysema all have increased airway obstruction. 32. The term used to specify the flow, pressure, and volume waveforms that are graphed relative
to time is called hysteresis. loop. waveform. scalar.
a. b. c. d.
ANS: D
Hysteresis can be thought of as a lagging of one of two associated phenomena; that is, two associated phenomena fail to coincide or occur simultaneously. The term scalar is used to specify the flow, pressure, and volume waveforms that are graphed relative to time (i.e., pressure, flow, and volume scalars). Basically, six shapes (waveforms) are produced with scalars during mechanical ventilation. The term loop is used to describe a graph of two variables plotted on the x and y coordinates, such as pressure–volume and flow–volume loops.
Chapter 10: Assessment of Respiratory Function Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. A pulse oximeter differentiates oxyhemoglobin from deoxygenated hemoglobin by which of
the following methods? Relating cyclical changes in light transmission through the sampling site Shining and comparing two wavelengths of light through the sampling site Direct measurement by a heated polarographic electrode applied to the skin Using a color sensing device that absorbs one wavelength of light through the skin
a. b. c. d.
ANS: B
A pulse oximeter uses spectrophotometry to differentiate between oxyhemoglobin and deoxygenated hemoglobin. Two wavelengths of light (660 and 940 nm) are shined through a sample site. Oxyhemoglobin absorbs more light at 940 nm (infrared [IR] light) than does deoxygenated hemoglobin. Deoxyhemoglobin absorbs more light at 660 nm. The use of cyclical changes in light transmission measured at the sampling site is the method to determine the pulse rate with a pulse oximeter. A heated polarographic electrode is used for transcutaneous partial pressure of oxygen (PtcO2) measurements. A color sensing device is used to detect the amount of carbon dioxide in exhaled gas. 2. An arterial blood gas should be done to confirm pulse oximetry findings less than a minimum
of a. b. c. d.
. 60% 70% 80% 90%
ANS: C
When a patient’s oxygen saturation measured by pulse oximeter (SpO2) is less than 80% an arterial blood gas should be drawn to confirm the patient’s oxygenation status because a pulse oximeter is generally accurate for oxygen saturations greater than 80%. 3. A pulse oximeter reading will be most accurate when used with a patient in which of the
following situations? An intensive care unit patient with hyperbilirubinemia A hypotensive patient receiving peripheral vasoconstrictors An emergency department patient with evidence of smoke inhalation An open heart patient receiving extracorporeal membrane oxygenation
a. b. c. d.
ANS: A
Hyperbilirubinemia does not appear to affect pulse oximetry measurements as do low perfusion states, which are caused by the use of peripheral vasoconstrictors or extracorporeal membrane oxygenation (ECMO). Carbon monoxide poisoning will lead to an overestimation of oxygen saturation measured by pulse oximeter (SpO2).
4. A patient arrives in the emergency department via ambulance following rescue from a house
fire. The instrument that would be most appropriate to assist the respiratory therapist in assessing this patient’s oxygenation status is which of the following? a. Capnograph b. Pulse oximeter c. Calorimeter d. CO-oximeter ANS: D
Laboratory CO-oximeters measure four types of hemoglobin: oxyhemoglobin (O2Hb), deoxygenated hemoglobin (HHb), carboxyhemoglobin (COHb), and methemoglobin (MetHb). This is beneficial for patients who are suffering from smoke inhalation. The COoximeter provides the actual O2Hb and the COHb. Carbon monoxide produces an erroneously high oxygen saturation measured by pulse oximeter (SpO2). Therefore, if smoke inhalation is suspected, a CO-oximeter should be used to evaluate the oxygen saturation. Capnography is the measurement of carbon dioxide concentrations in exhaled gases and is used to assess proper airway placement. Calorimetry allows the clinician to estimate energy expenditure from measurements of oxygen consumption (O2) and carbon dioxide production (CO2). This measurement may be useful when weaning a patient from mechanical ventilation. 5. While trying to use a finger probe to assess a patient’s oxygenation status, the respiratory
therapist finds that the pulse rate and the ECG monitor heart rate are not consistent and the oxygen saturation measured by pulse oximeter (SpO2) reading is blank. The patient is awake, alert, and in no obvious respiratory distress. The respiratory therapist should first take which of the following actions? 1. Change the probe site. 2. Draw an arterial blood gas. 3. Adjust the probe position on the finger. 4. Remove the probe and perform a capillary refill test. a. 1 and 2 only b. 2 and 3 only c. 3 and 4 only d. 1 and 4 only ANS: C
The fact that the patient is awake, alert, and in no respiratory distress decreases the likelihood that the problem is with the patient. Therefore, the first action in this case should not be to draw an arterial blood gas (ABG). In cases where the pulse oximeter cannot identify a pulsatile signal, the oxygen saturation measured by pulse oximeter (SpO2) reading may not be present. This could be alleviated by adjusting the probe position on the finger. Absent SpO2 readings could also be due to low perfusion states. Performing a capillary refill test on the finger being used for the probe would show whether or not the finger has adequate blood flow. If this is true, the next step would be to change the site. 6. Pulse oximetry is most useful in which of the following situations? a. Determining when to extubate an adult b. Prescribing oxygen therapy for neonates c. Monitoring patients undergoing chest physical therapy d. Establishing initial oxygen necessity for homecare patients ANS: C
The oxygen status of a patient being considered for extubation needs to be assessed by an arterial blood gas, not by pulse oximetry, because not only does the patient’s oxygen status need assessment, but the acid–base balance does as well. Pulse oximetry is not used as a basis for prescribing oxygen therapy in neonates. Neonatologists prefer to base oxygen therapy decisions on arterial partial pressure of oxygen (PaO2) rather than oxygen saturation. Pulse oximetry is useful for monitoring the oxygen status of patients undergoing chest physical therapy because it gives immediate results and is used for continuous monitoring. Pulse oximetry may not be as useful in prescribing oxygen therapy for homecare patients. 7. During which phase of a capnograph does alveolar gas containing carbon dioxide (CO2) mix
with gas from the anatomical airways and the CO2 concentration rises? Phase 1 Phase 2 Phase 3 Phase 4
a. b. c. d.
ANS: B
In phase 1, the initial gas exhaled is from the conducting airways, which contain low levels of carbon dioxide (CO2) from inspired air. During phase 2, alveolar gas containing CO2 mixes with gas from the anatomical airways and the CO2 concentration rises. In phase 3, the curve plateaus as alveolar gas is exhaled. In phase 4, the concentration falls to zero. 8. During which phase of a capnogram does inhalation occur? a. Phase 1 b. Phase 2 c. Phase 3 d. Phase 4 ANS: D
During inhalation the capnogram will have a zero reading because there is no exhalation of carbon dioxide (CO2). As soon as the exhalation phase begins there is rise of the waveform. In phase 1, the initial gas exhaled is from the conducting airways, which contain low levels of CO2 from inspired air. During phase 2, alveolar gas containing CO2 mixes with gas from the anatomical airways and the CO2 concentration rises. In phase 3, the curve plateaus as alveolar gas is exhaled. In phase 4, the concentration falls to zero because inspiration is occurring. 9. The respiratory therapist has just stopped postural drainage for a 24-year-old patient with
cystic fibrosis because of shortness of breath and slight cyanosis in the “head-down” position. The respiratory therapist should recommend which of the following adjustments to therapy? a. Continue postural drainage and monitor patient with capnography. b. Use only upright or flat postural drainage positions and draw an arterial blood gas (ABG). c. Administer oxygen via nasal cannula and monitor with pulse oximetry. d. Use a transcutaneous partial pressure of oxygen (PtcO2) monitor to assess the extent of hypoxemia. ANS: C
The presence of slight cyanosis and shortness of breath in the “head-down” position is indicative of hypoxemia. The respiratory therapist should administer supplemental oxygen via nasal cannula (possibly 1–2 L/min) and monitor the patient with a continuous pulse oximetry. Capnography is not useful in detecting hypoxemia. Using flat postural drainage positions where the head is not lower than the shoulders has not been proven to be effective. 10. A patient receiving mechanical ventilation is being continuously monitored for oxygen
saturation measured by pulse oximeter (SpO2) for the past 48 hours. When initially applied, the SpO2 and the arterial oxygen saturation (SaO2), as well as the pulse on the pulse oximeter, ECG, and manual pulse, were consistent. During clinical rounds, the respiratory therapist notices that although the probe is appropriately placed and capillary refill is normal, the SpO2 reading is down to 90% from 95%. The most appropriate immediate action is to do which of the following? a. Replace the probe. b. Reposition the patient. c. Draw an arterial blood gas. d. Move the probe to a different site. ANS: C
The oxygen saturation measured by pulse oximeter (SpO2) has dropped from 95% to 90%. Since the SpO2 and arterial oxygen saturation (SaO2) previously correlated, this situation could mean that the patient is becoming hypoxemic. The probe is appropriately placed, so changing sites is not appropriate. The patient has already been checked for and has adequate circulation to the site of the probe, so moving the probe to a site with more perfusion is not appropriate. Therefore, the patient needs to have an arterial blood gas to ascertain the SaO2 and partial pressure of oxygen (PaO2). 11. The partial pressure of end tidal carbon dioxide (PetCO2) reading is taken at what point in the
figure?
a. b. c. d.
Point A Point B Point C Point D
ANS: C
Point C shows the concentration of carbon dioxide (CO2) at the end of the alveolar phase, just before inspiration begins. This occurs in phase 3 of the four phases of a capnogram. Point A depicts phase 1, which is the initial gas exhaled from the conducting airways. As a person exhales, the amount of CO2 in the exhaled gas increases. The amount of CO2 exhaled levels off at point B. This coincides with phase 4 or the alveolar plateau. Point D is showing the fall in CO2 that occurs during inspiration. 12. A patient in the intensive care unit is receiving mechanical ventilation, has a pulmonary artery
catheter in place, and is being monitored continuously with a capnometer. The patient’s arterial partial pressure of carbon dioxide (PaCO2) is 41 mm Hg and the partial pressure of end tidal carbon dioxide (PetCO2) is 36 mm Hg. There is a sudden decrease in the PetCO2 to 18 mm Hg causing an alarm to sound. The most likely cause of this development is which of the following? a. Hypovolemia b. Apneic episode c. Pulmonary embolism d. Increased cardiac output ANS: C
Pulmonary embolism will cause a decrease in blood flow to the lungs. This increases alveolar dead space and leads to a decrease in the partial pressure of end tidal carbon dioxide (PetCO2). Hypovolemia would also cause a decrease in the PetCO2, but it would not occur as suddenly as it did in this situation. The fact that the patient has an indwelling pulmonary artery catheter increases the risk of developing a pulmonary embolism, which often will have a quick onset. An apneic episode would have increased the PetCO2. An increased cardiac output would increase the PetCO2 because increases in cardiac output result in better perfusion of the alveoli and a rise in PetCO2. 13. The capnogram in the figure is indicative of which of the following conditions?
a. b. c. d.
Chronic obstructive pulmonary disease (COPD) Cardiac arrest Hyperventilation Pulmonary embolism
ANS: A
Phase 3 becomes indistinguishable when physiological dead space increases, as in chronic obstructive pulmonary disease (COPD), and causes the capnogram to appear as it does in the figure. A cardiac arrest would lower the graph line to zero. Hyperventilation will decrease the alveolar plateau, but its shape would remain the same as a normal capnogram. A pulmonary embolism would also cause a drop in the alveolar plateau.
14. For a given minute ventilation, partial pressure of end tidal carbon dioxide (PetCO2) is a
function of which of the following? 1. Metabolic rate 2. Cardiac output 3. Alveolar dead space 4. Physiological shunt a. 1 and 3 only b. 2 and 4 only c. 2, 3, and 4 only d. 1, 2, and 3 only ANS: D
Changes in metabolic rate cause changes in partial pressure of end tidal carbon dioxide (PetCO2). For instance, fever and shivering increase the metabolism and increase the PetCO2. A change in cardiac output will change PetCO2 because the heart transports the blood that carries the carbon dioxide (CO2) to the lungs for elimination. Increases in cardiac output will increase PetCO2. A change in dead space ventilation will also cause changes in the PetCO2. Increasing dead space will decrease the PetCO2. 15. The normal range for arterial-to-end tidal partial pressure of carbon dioxide [P(a-et)CO2] is
which of the following? 2–4 mm Hg 4–6 mm Hg 6–8 mm Hg 8–10 mm Hg
a. b. c. d.
ANS: B
The arterial-to-end tidal partial pressure of carbon dioxide [P(a-et)CO2] for tidal breathing should be approximately 4–6 mm Hg. 16. During shift report, the day shift respiratory therapist informs the night shift respiratory
therapist about a freshly postoperative patient who is receiving full support via mechanical ventilation. At the time of the last patient-ventilator system check the patient had not awaken from anesthesia. During first round on the day shift the respiratory therapist notes the capnography shown in the figure. The most appropriate action to take would be to do which of the following?
a. Administer a bronchodilator. b. Begin the weaning process. c. Fix the leak in the sampling line.
d. Reinflate the ET tube cuff. ANS: B
The figure shows a patient whose capnography is demonstrating spontaneous respiratory efforts during mechanical ventilation. This corresponds to the patient’s waking up from anesthesia. With all else stable, the next step would be to begin the weaning process. 17. The area under the curve of a single-breath carbon dioxide (SBCO2) curve represents which of
the following? Tidal volume Alveolar dead space Physiological dead space Effective alveolar ventilation
a. b. c. d.
ANS: D
The area under the single-breath carbon dioxide (SBCO2) curve represents alveolar volume. This is known as phase 3 on the SBCO2 curve. Phase 1 is the anatomical dead space volume. Phase 2 is a transitional phase between anatomical dead space and alveolar volume. 18. The change in the single-breath carbon dioxide (CO2) curve from “A” to “B” shown in the
figure may be a result of which of the following?
a. b. c. d.
Hypervolemia Decreased positive end-expiratory pressure (PEEP) Increased mean airway pressure Excessive bronchodilator administration
ANS: C
The change in the figure shows an increase in phase 1 and a decrease in phase 2 of the singlebreath carbon dioxide (SBCO2) curve. An increase in phase 1 may be caused by an increase in anatomical dead space. This is possible as a result of increased airway obstruction or excessive positive end-expiratory pressure (PEEP). Therefore, answers “B” and “D” cannot be correct. A decrease in phase 2 means there is a decrease in venous return or an increase in intrathoracic pressure. This could be caused by hypovolemia or an increased intrathoracic pressure as seen with increased mean airway pressures. Therefore, answer “A” cannot be correct. Answer “C” is a measure of increased intrathoracic pressure and is the correct answer. 19. Which of the following situations will cause an increase in the single-breath carbon dioxide
(SBCO2) curve? a. Decreased metabolic rate and decreased ventilation
b. Decreased metabolic rate and increased ventilation c. Increased metabolic rate and increased ventilation d. Increased metabolic rate and decreased ventilation ANS: D
The same cause for an increase in arterial partial pressure of carbon dioxide (PaCO2) will increase the single-breath carbon dioxide (SBCO2) curve. An increase in metabolic rate will increase the carbon dioxide (CO2) production in the body. This, accompanied by either no change in ventilation or a decrease in ventilation, will cause the amount of CO2 in the body to increase and thus cause the amount of CO2 exhaled to increase. The only combination that will do this is “D,” increased metabolic rate and decreased ventilation. 20. The area represented by the letter “Y” in the figure is which of the following?
a. b. c. d.
End tidal carbon dioxide (EtCO2) Alveolar ventilation Alveolar dead space Airway dead space
ANS: C
The end tidal carbon dioxide (EtCO2) is represented by the very end of the waveform. The alveolar ventilation is represented by the area under the curve, which is “X.” The alveolar dead space is represented by the difference between the arterial partial pressure of carbon dioxide (PaCO2) and the EtCO2 line, which is “Y.” The airway dead space is represented by “Z.” 21. A patient is receiving mechanical ventilation with a fractional inspired oxygen (FIO2) of 0.85
and a positive end-expiratory pressure (PEEP) of 5 cm H2O. His arterial partial pressure of oxygen (PaO2) is 68 mm Hg, arterial oxygen saturation (SaO2) is 88%, and partial pressure of end tidal carbon dioxide (PetCO2) is 32 mm Hg. Over the next few minutes his PEEP is titrated resulting in the following data: Time FIO2 SpO2 (%) PetCO2 (mm Hg) PEEP (cm H2O) 0600 0.85 5 88 30 0630 0.85 8 88 30 0650 0.85 10 90 32 0720 0.80 12 93 34 0740 0.80 15 90 25 At 0740 the single-breath carbon dioxide (SBCO2) curve shifted to the right. What action should the respiratory therapist take at this time? a. Increase the FIO2 to 0.90.
b. Reduce the set tidal volume. c. Continue to increase the PEEP. d. Reduce the PEEP to 12 cm H2O. ANS: D
The increase in positive end-expiratory pressure (PEEP) to 15 cm H2O seems to have decreased pulmonary perfusion because of overinflation of the alveoli. This is evident by the decrease in the partial pressure of end tidal carbon dioxide (PetCO2) to 25 mm Hg and the right shift in the single-breath carbon dioxide (SBCO2) curve. Increasing the fractional inspired oxygen (FIO2) will not address this problem. Reducing the set tidal volume will increase the PetCO2 but will not improve the pulmonary circulation. Continuing to increase the PEEP will further reduce pulmonary perfusion and cause more dead space. Reducing the PEEP back to 12 cm H2O will optimize the PEEP and reduce overinflation. 22. Exhaled nitric oxide is used to monitor the effectiveness of which drug used in the treatment
of asthma? Anticholinergic bronchodilators adrenergic bronchodilators Inhaled corticosteroids Leukotriene inhibitors
a. b. c. d.
ANS: C
Exhaled nitric oxide (NO) is currently used as a marker for airway inflammation associated with asthma. Monitoring the level of exhaled NO can also be used to monitor the effectiveness of inhaled corticosteroid in the treatment of asthmatic patients. 23. The condition that is associated with a reduction in exhaled nitric oxide is which of the
following? Alveolitis Cystic fibrosis Chronic bronchitis Airway viral infection
a. b. c. d.
ANS: B
See Box 10-3 in the text for a list of conditions that reduce and elevate levels of exhaled nitric oxide. 24. What type of electrode is used by a transcutaneous partial pressure of oxygen (PtcO2) device? a. Galvanic b. Polarographic c. Paramagnetic d. Stow–Severinghaus ANS: B
A heated Clark or polarographic electrode is used to monitor the transcutaneous partial pressure of oxygen. The Stow–Severinghaus electrode is used in the measurement of transcutaneous carbon dioxide (CO2) partial pressure. Polarographic and Galvanic electrodes are types of oxygen analyzers that use chemical reactions to measure oxygen concentrations in gas mixtures.
25. To properly operate, the transcutaneous partial pressure of oxygen electrode needs to be at
what temperature range? 32–35 C 36–39 C 42–45 C 46–49 C
a. b. c. d.
ANS: C
The transcutaneous partial pressure of carbon dioxide (PtcO2) electrode is heated to between 42 C and 45 C to produce capillary vasodilation below the surface of the electrode. This will improve diffusion of gases across the skin. If the PtcO2 temperature is lower than this range, the results will not be reliable. A temperature higher than this range will produce skin burns. 26. A transcutaneous partial pressure of oxygen (PtcO2) reading is reliable in which of the
following situations? Hypothermia Septic shock Infant respiratory distress syndrome Elevated peripheral (cutaneous) resistance
a. b. c. d.
ANS: C
A reduction in cutaneous circulation will dramatically affect the measurement of transcutaneous partial pressure of oxygen (PtcO2). This situation is caused by hypothermia, septic shock, and elevated peripheral resistance. PtcO2 measurements have been shown to be reliable for neonates. 27. What type of electrode is used by a transcutaneous partial pressure of carbon dioxide (PtcCO2)
device? Galvanic Polarographic Paramagnetic Stow–Severinghaus
a. b. c. d.
ANS: D
The Stow–Severinghaus electrode is used in the measurement of transcutaneous carbon dioxide partial pressure. A Clark or polarographic electrode is used to monitor the transcutaneous partial pressure of oxygen. Polarographic and Galvanic electrodes are types of oxygen analyzers that use chemical reactions to measure oxygen concentrations in gas mixtures. 28. During calibration of a transcutaneous monitor the respiratory therapist notices a signal drift.
The respiratory therapist should do which of the following? Increase the probe temperature. Replace the monitor and call for repair. Add more electrolyte gel to the patient’s skin. Change the electrolyte and sensor’s membrane.
a. b. c. d.
ANS: D
A signal drift on a transcutaneous monitor should be addressed by changing the electrode and sensor’s membrane. The electrode and the sensor’s membrane should be changed weekly due to the evaporation of the electrolyte solution caused by the heating of the electrode. Increasing the probe temperature may cause patient burns if it is over 45 C. The signal drift does not necessarily mean that the monitor itself needs to be taken out of service. Adding more gel to the patient’s skin will help with gas diffusion during measurement only. 29. How often should the respiratory therapist reposition the sensor of a transcutaneous monitor? a. 30 min to 1 hour b. 1–3 hours c. 4–6 hours d. 7–9 hours ANS: C
Burns can occur because the site of measurement needs to be heated to between 42 C and 45 C. Repositioning the sensor every 4–6 hours will help avoid this problem. 30. The clinical data that should be recorded when making transcutaneous measurements include
which of the following? 1. Electrode temperature 2. Skin temperature 3. Probe placement 4. Fractional inspired oxygen (FIO2) a. 1 and 3 only b. 1 and 2 only c. 2, 3, and 4 only d. 1, 2, 3, and 4 ANS: D
The electrode temperature must be documented to ensure that the temperature stays within the range of 42–45 C. The skin temperature should be noted to assess the patient’s peripheral perfusion. The probe placement should be noted to ensure that the probe is being moved to different sites every 4–6 hours. The fractional inspired oxygen (FIO2) should be documented to determine the need for an increase or decrease in the amount of supplemental oxygen the patient is receiving. 31. Components of an indirect calorimeter may include which of the following?
1. Pressure manometer 2. Pneumotachometer 3. Pressure-sensitive transducer 4. Oxygen and carbon dioxide analyzers a. 1 and 3 only b. 2 and 4 only c. 1, 3, and 4 only d. 2, 3, and 4 only ANS: B
Indirect calorimeters contain analyzers for measuring the concentration of inspired and expired gases, oxygen (O2) and carbon dioxide (CO2), pneumotachometers, turbine flowmeters, or ultrasonic vortex flowmeters to measure volume and flow, temperaturesensitive, solid-state transducers to measure barometric pressure and exhaled gas temperatures. 32. An energy expenditure (EE) of 60 kcal/hr/m2 for an adult is indicative of which of the
following conditions? Burns Sedation Starvation Hypothermia
a. b. c. d.
ANS: A
An energy expenditure (EE) of 30–40 kcal/hr/m2 is normal for an adult. The EE of 60 kcal/hr/m2 is greater than 120% of predicted and is considered a hypermetabolic state. Burns create a hypermetabolic state. Starvation, sedation, and hypothermia create hypometabolic states. 33. An energy expenditure (EE) of 20 kcal/hr/m2 for an adult is indicative of which of the
following conditions? Pregnancy Starvation Hyperthyroidism Stimulant drugs
a. b. c. d.
ANS: B
An energy expenditure (EE) of 30–40 kcal/hr/m2 is normal for an adult. The EE of 20 kcal/hr/m2 is less than 80% of predicted and is considered a hypometabolic state. Starvation creates a hypometabolic state. Pregnancy, hyperthyroidism, and stimulant drugs create hypermetabolic states. 34. The respiratory quotient (RQ) value associated with substrate utilization patterns in normal,
healthy individuals is which of the following? 0.7 0.8 0.9 1.0
a. b. c. d.
ANS: B
A healthy adult consuming a typical American diet will have a respiratory quotient (RQ) range from 0.80 to 0.85. An RQ of 0.7 is indicative of lipid metabolism as seen in prolonged starvation or severe sepsis. The RQ for the metabolism of pure carbohydrates is 1.0. An RQ of 0.9 would mean that the individual is consuming a higher amount of carbohydrates than a normal diet. 35. A patient whose carbon dioxide (CO2) production is 390 mL/min and oxygen (O2)
consumption is 375 mL/min is most likely experiencing which of the following? a. Ketosis b. Severe sepsis c. Hyperventilation
d. Too much carbohydrate intake ANS: C
The respiratory quotient (RQ) is the ratio of carbon dioxide (CO2) production to oxygen (O2) consumption. This patient has an RQ (390/375) of 1.04. Ketosis causes the RQ to be less than 0.7. Severe sepsis is associated with RQ levels of approximately 0.7. Hyperventilation is associated with RQ levels greater than 1.0. Pure carbohydrate RQ is 1.0. 36. A mechanically ventilated patient with chronic obstructive pulmonary disease is in the process
of being weaned from mechanical ventilation. A diet containing which of the following will be most beneficial to this process? a. High protein, low fats, and carbohydrates b. Low fats and proteins, high carbohydrates c. Low carbohydrate with increased fats and proteins d. Equal amounts of carbohydrates, fats, and proteins ANS: C
Diets with a high percentage of carbohydrates will raise the amount of carbon dioxide (CO2) a patient produces. This will overburden a patient with limited ventilatory reserves, as with chronic obstructive pulmonary disease (COPD). The added CO2 is greater than the patient’s ventilatory capacity, and when attempting to maintain spontaneous breathing the patient will fail to wean. 37. The newest types of mechanical ventilators use which of the following devices to measure
airway pressures? Barometers Aneroid manometers Electromechanical transducers Variable orifice pneumotachometers
a. b. c. d.
ANS: C
Barometers are used to measure atmospheric (barometric) pressure. Older ventilators incorporated an aneroid manometer into the ventilator circuit. Variable orifice pneumotachometers are used to measure flow. The devices that are used in the current ventilators today are the electromechanical transducers, which include piezoelectric transducers, variable capacitance transducers, and strain gauge transducers. 38. Which of the following actions is indicated when a disparity exists between SpO2, SaO2, and
the clinical presentation of a patient? a. Move the probe to an alternate site to check for SpO2. b. Replace the pulse oximeter probe. c. Measure arterial oxygen saturation by CO-oximetry. d. Disregarding the SaO2. ANS: C
Laboratory CO-oximeters measure all four types of hemoglobin by using separate wavelengths of light to identify each species, whereas pulse oximeters use only two wavelengths to quantify the amount of O2HB and HHB present. 39. To measure plateau pressure, inspiration should be held for how many seconds? a. 1–2
b. 2–3 c. 3–4 d. 4–5 ANS: A
Plateau pressure requires the establishment of a period of no-flow for 1–2 s to allow pressure equilibration by the redistribution of the tidal volume and stress relaxation. This maneuver increases inspiratory time and if held longer than 2 s may cause barotrauma. 40. Select the ventilator flowmeter that will read accurately when used with heliox. a. Turbine b. Vortex ultrasonic c. Variable capacitance d. Variable orifice pneumotachometer ANS: B
Vortex ultrasonic flowmeters are not affected by the viscosity, density, or temperature of the gas being measured. The turbine and variable orifice pneumotachometer will not be accurate when using heliox because of its decreased density. A variable capacitance device is a transducer used to measure airway pressure. 41. Bidirectional flow can be measured by which of the following devices? a. Turbine flowmeter b. Piezoelectric transducer c. Ultrasonic vortex flowmeter d. Variable orifice pneumotachometer ANS: D
The turbine and ultrasonic flowmeters are inaccurate with bidirectional flows. The piezoelectric transducer measures airway pressures. The variable orifice pneumotachometer is a bidirectional flow measuring device. 42. During the application of positive end-expiratory pressure (PEEP), the monitoring of which
pressure will alert the respiratory therapist specifically to alveolar overdistention? Peak inspiratory pressure (PIP) Plateau pressure (Pplat) Mean airway pressure Transairway pressure (PTA)
a. b. c. d.
ANS: B
The plateau pressure (Pplat) is the pressure required to overcome only elastance. When positive end-expiratory pressure (PEEP) is applied, the alveolar pressure will rise. This will result in a higher Pplat. If overdistention occurs the Pplat will rise immediately. Peak inspiratory pressure (PIP) reflects the total force that must be applied to overcome both elastance and airway resistance offered by the patient-ventilator system. The mean airway pressure represents the average pressure recorded during the entire respiratory cycle. It is influenced by PIP, PEEP, inspiratory time, and total cycle time. The mean airway pressure is not a specific monitor for optimizing PEEP. The PIP will increase in the face of alveolar overdistention, but it is not specific enough to rely on as the sole measurement to identify overdistention. The transairway pressure is the difference between the PIP and the Pplat and represents the amount of pressure needed to overcome airway resistance (all frictional forces). The transairway pressure will not reflect alveolar overdistention because when alveolar overdistention happens both the PIP and the Pplat will rise, and the difference between the two will remain constant unless there is an unrelated change in airway resistance. 43. A patient-ventilator system check reveals the following information: peak inspiratory pressure
(PIP) 27 cm H2O, positive end-expiratory pressure (PEEP) 5 cm H2O, plateau pressure (Pplat) 14 cm H2O, inspiratory time (TI) 0.75 s, and set frequency 20/min. Calculate the mean airway pressure. a. 6.75 cm H2O b. 7.75 cm H2O c. 11.75 cm H2O d. 12.37 cm H2O ANS: B
44. A patient-ventilator system check reveals the following information: peak inspiratory pressure
(PIP) 32 cm H2O, positive end-expiratory pressure (PEEP) 12 cm H2O, plateau pressure (Pplat) 20 cm H2O, inspiratory time (TI) 1 s, and set frequency 12/min. Calculate the mean airway pressure. a. 4 cm H2O b. 8 cm H2O c. 12 cm H2O d. 14 cm H2O ANS: D
45. Calculate the dynamic compliance given the following clinical data: tidal volume 500 mL,
peak inspiratory time (PIP) 35 cm H2O, plateau pressure (Pplat) 20 cm H2O, positive endexpiratory pressure (PEEP) 5 cm H2O, and tubing compliance (CT) 2.5 mL/cm H2O. a. 11.8 mL/cm H2O b. 14.2 mL/cm H2O
c. 25 mL/cm H2O d. 46.2 mL/cm H2O ANS: B
Dynamic compliance = tidal volume (VT) 5) 2.5]/(35 5) = 14.2 mL/cm H2O.
[(PIP PEEP) CT]/(PIP PEEP) = 500
[(35
46. Calculate dynamic compliance given the following clinical data: tidal volume 600 mL, peak
inspiratory pressure (PIP) 28 cm H2O, plateau pressure (Pplateau) 15 cm H2O, positive endexpiratory pressure (PEEP) 10 cm H2O, and CT 2 mL/cm H2O. a. 30.2 mL/cm H2O b. 31.3 mL/cm H2O c. 38 mL/cm H2O d. 44.1 mL/cm H2O ANS: B
Dynamic compliance = tidal volume (VT) [(PIP PEEP) CT]/(PIP PEEP) = 600 10) 2]/(28 10) = (600 36)/18 = 31.3 mL/cm H2O.
[(28
47. Calculate the static compliance given the following clinical data: tidal volume 500 mL, peak
inspiratory pressure (PIP) 35 cm H2O, plateau pressure (Pplat) 25 cm H2O, positive endexpiratory pressure (PEEP) 12 cm H2O, measured unintended positive end-expiratory pressure (auto-PEEP) 3 cm H2O, and tubing compliance (CT) 2.5 mL/cm H2O. a. 17.5 mL/cm H2O b. 34 mL/cm H2O c. 36 mL/cm H2O d. 47.5 mL/cm H2O ANS: D
Static compliance = tidal volume (VT) [(Pplat PEEP) CT]/(Pplat PEEP) = 500 2.5]/25 15 = (500 25)/10 = 47.5 mL/cm H2O.
[(25
15)
48. Calculate the static compliance given the following clinical data: tidal volume 600 mL, peak
inspiratory pressure (PIP) 40 cm H2O, plateau pressure (Pplat) 30 cm H2O, positive endexpiratory pressure (PEEP) 15 cm H2O, and tubing compliance (CT) 2 mL/cm H2O. a. 14.5 mL/cm H2O b. 38 mL/cm H2O c. 55 mL/cm H2O d. 58 mL/cm H2O ANS: B
Static compliance = Tidal volume (VT) [(Pplat PEEP) CT]/(Pplat PEEP) = 600 15) 2]/30 15 = 570/15 = 38 mL/cm H2O.
[(30
49. Calculate the airway resistance given the following clinical data: flow rate 60 L/min, peak
inspiratory pressure (PIP) 42 cm H2O, plateau pressure (Pplat) 15 cm H2O, and positive endexpiratory pressure (PEEP) 5 cm H2O. a. 10 cm H2O/(L/s) b. 30 cm H2O/(L/s) c. 37 cm H2O/(L/s) d. 42 cm H2O/(L/s)
ANS: B
60 L/min = 1 L/s. Raw = (PIP Pplat)/(L/s) = (42 15)/1 = 30 cm H2O/(L/s). 50. Calculate the airway resistance given the following clinical data: flow rate 60 L/min, PIP 28
cm H2O, Pplat 21 cm H2O, and PEEP 8 cm H2O. 7 cm H2O/(L/s) 13 cm H2O/(L/s) 20 cm H2O/(L/s) 28 cm H2O/(L/s)
a. b. c. d.
ANS: A
60 L/min = 1 L/s. Raw = (PIP Pplat)/(L/s) = (28 21)/1 = 7 cm H2O/(L/s). 51. The energy required to move gas through the airways and expand the thorax is known as
which of the following? Airway resistance Dynamic compliance Intrinsic work of breathing Extrinsic work of breathing
a. b. c. d.
ANS: C
Intrinsic work of breathing is a result of work done to overcome normal elastic and resistive forces and work to overcome a disease process affecting normal workloads in the lungs and thorax. Airway resistance is the opposition to airflow from nonelastic forces of the lung. Dynamic compliance is a measurement of the ease of movement of gas through the airways. The work of breathing is a result of the airway resistance, dynamic compliance, and static compliance. 52. An increase in intrinsic work of breathing due to a decrease in static compliance is caused by
which of the following? Emphysema Bronchospasm Pulmonary fibrosis Airway inflammation
a. b. c. d.
ANS: C
Static compliance is influenced by the elastic characteristics of the lungs and thorax. A decrease in static compliance is due to either the lungs becoming stiffer or the thorax’s inability to stretch to accommodate volume in the lungs. Pulmonary fibrosis is a pathophysiological condition that causes the alveoli to become stiffer due to scarring. Therefore, pulmonary fibrosis will increase a patient’s work of breathing due to decreases in the static compliance. Emphysema causes an increase in static compliance due to the loss of elastic properties of the lungs and also an increase in airway resistance because of bronchospasm, airway inflammation, and airway edema. Bronchospasm and airway inflammation lead to increased airway resistance and decreased dynamic compliance. 53. The best assessment of the function of the diaphragm during inspiration is obtained by
measuring which of the following? a. Airway resistance b. Pressure–time product
c. Pressure–volume curve d. Maximum inspiratory pressure ANS: B
The pressure–time product is a way of estimating the contributions of the diaphragm during inspiration. It is probably a better indication of a patient’s effort to breathe than measurement of work derived from pressure–volume curve. Airway resistance is a measure of how much opposition there is to gas movement through the airways. An increase in airway resistance will cause the diaphragm to work harder. However, airway resistance is not a direct way of assessing the function of the diaphragm. Maximum inspiratory pressure provides nonspecific information about the function of the respiratory muscles in general, not specifically the diaphragm. 54. At which point in the pressure–time curve of a spontaneous breath should the
transdiaphragmatic pressure be greatest? Mid-inspiration Mid-expiration End of exhalation Beginning of inspiration
a. b. c. d.
ANS: A
The transdiaphragmatic pressure is the difference between the gastric and esophageal pressures, as measured during the respiratory cycle. The greatest distance between these two pressures during the respiratory cycle is at the middle of inspiration, when the esophageal pressure is at its lowest point. At mid-expiration the gastric and esophageal pressure difference is at its smallest point. See Figure 10-25. 55. Which of these two parameters does a pulse oximeter measure?
1. O2Hb 2. Hb 3. COHb 4. MetHb a. 1 and 2 b. 1 and 3 c. 2 and 3 d. 3 and 4 ANS: A
Pulse oximetry provides continuous, noninvasive measurements of arterial oxygen saturation. A sensor is placed over a digit, an earlobe, the forehead or the bridge of the nose; this sensor measures the absorption of selected wavelengths of light beamed through the tissue (Fig. 101). For example, oxyhemoglobin can be differentiated from deoxygenated hemoglobin by shining two wavelengths of light (660 and 940 nm) through the sampling site. As Figure 10-2 illustrates, at a wavelength of 660 nm (red light), deoxygenated hemoglobin absorbs more light than oxyhemoglobin. Conversely, oxyhemoglobin absorbs more light at 940 nm (infrared light [IR]) than does deoxygenated hemoglobin. 56. The initial gas exhaled from the conducting airways reading is taken at what point in the
figure?
a. b. c. d.
Point A Point B Point C Point D
ANS: A
Point C shows the concentration of carbon dioxide (CO2) at the end of the alveolar phase, just before inspiration begins. This occurs in phase 3 of the four phases of a capnogram. Point A depicts phase 1, which is the initial gas exhaled from the conducting airways. As a person exhales, the amount of CO2 in the exhaled gas increases. The amount of CO2 exhaled levels off at point B. This coincides with phase 4 or the alveolar plateau. Point D is showing the fall in CO2 that occurs during inspiration.
Chapter 11: Hemodynamic Monitoring Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Which of the following describes the filling pressure of the ventricle at the end of ventricular
diastole? Preload Afterload Dicrotic notch Ejection fraction
a. b. c. d.
ANS: A
The definition of preload is the filling pressure of the ventricle at the end of ventricular diastole. 2. Which measurement is typically used to indicate right ventricular preload? a. Right atrial pressure (RAP) b. Pulmonary artery occlusion pressure (PAOP) c. Right ventricular end-diastolic pressure (RVEDP) d. Ejection fraction ANS: C
Preload is the filling pressure of the ventricle at the end of ventricular diastole and is estimated by measuring the end-diastolic pressures. In the case of right ventricular preload the measurement would be right ventricular end-diastolic pressure. 3. Which of the following can be used to estimate the contractility of the ventricles? a. Ejection fraction b. Systemic vascular resistance c. Pulmonary vascular resistance d. Right and left ventricular end-diastolic pressure ANS: A
The ejection fraction is a way of estimating the force that the ventricle generates during each cardiac cycle. It is calculated as the ratio of the stroke volume to the ventricular end-diastolic volume. Systemic vascular resistance is used to describe the afterload that the left ventricle must overcome to eject blood into the systemic circulation. The pulmonary vascular resistance reflects the afterload that the right ventricle must overcome to eject blood into the pulmonary circulation. The right ventricular end-diastolic pressure is used as an indicator of the right ventricular preload and the left ventricular end-diastolic pressure is used to indicate left ventricular preload. 4. Calculate the ejection fraction of a female patient with a stroke volume of 40 mL and an end-
diastolic volume of 125 mL. a. 0.32 b. 3.1 c. 85 d. 165
ANS: A
Ejection fraction is calculated using the ratio of stroke volume to the ventricular end-diastolic volume. In this case the ejection fraction is . 5. Which of the following is an indication of left ventricular afterload? a. Ejection fraction b. Systemic vascular resistance c. Pulmonary vascular resistance d. Left ventricular end-diastolic pressure ANS: B
The systemic vascular resistance is the resistance the left ventricle must contract against to eject blood into the systemic circulation. Ejection fraction is a measurement of contractility. Pulmonary vascular resistance is the resistance the right ventricle must contract against to eject blood into the pulmonary circulation. Left ventricle end-diastolic pressure (LVEDP) is used to estimate left ventricular preload. 6. What is the most determining factor for preload? a. Contractility b. Venous return c. Ejection fraction d. Vascular resistance ANS: B
Preload, the filling pressure of the ventricle at the end of ventricular diastole is dependent on the level of venous return and in addition the compliance of the ventricles. Contractility is the force that the ventricle generates during each cardiac cycle and is estimated using the ejection fraction. Vascular resistance is a measurement used to determine the afterload of a ventricle, or the force the heart needs to overcome to eject the blood from the ventricles. 7. Which of the following will cause an increase in systemic vascular resistance? a. Decrease left ventricular preload. b. Increase right ventricular preload. c. Increase left ventricular afterload. d. Decrease right ventricular afterload. ANS: C
Afterload is increased when aortic pressure and systemic vascular resistance are increased, by aortic valve stenosis, and by ventricular dilation. When afterload increases, there is an increase in end-systolic volume and a decrease in stroke volume. Afterload does not immediately alter preload; however, preload changes secondarily to changes in afterload. Increasing afterload reduces stroke volume and increases left ventricular end-diastolic pressure (LVEDP) (i.e., increases preload). This occurs because the increase in end-systolic volume is added to the venous return into the ventricle and this increases end-diastolic volume. This increase in preload activates the Frank-Starling mechanism to partially compensate for the reduction in stroke volume caused by the increase in afterload. 8. Which of the following is the main component of a hemodynamic monitoring system? a. Plethysmograph b. Pneumotachometer
c. Sphygmomanometer d. Strain gauge transducer ANS: D
Hemodynamic monitoring systems consist of equipment that detects small physiological signal (vascular pressure) changes and converts them to electrical impulses, which can then be amplified and recorded on a cathode ray tube (CRT) monitor or strip chart recorder. A strain gauge transducer is utilized to measure vascular pressure. 9. Which of the following is the function of the transducer in the invasive vascular monitoring
system? Measure the flow of fluid in the catheter. Convert the fluid pressure to an electrical signal. Connect to the thermistor to measure cardiac output. Amplify the electrical signal so it may be seen on the monitor.
a. b. c. d.
ANS: B
The transducer has two main compartments. One, called the dome, contains the fluid that enters it from a plastic line connected to the indwelling catheter. The dome is separated from the electrical portion of the transducer by a flexible diaphragm. Changes in fluid pressure result in movement of the diaphragm, which causes an increase or decrease in the length of the wires of the Wheatstone bridge contained in the electrical portion of the transducer. The transducer is therefore able to detect small physiological signal changes and convert them to electrical impulses or signals. 10. Which of the following statements is true concerning the insertion of a radial arterial line?
1. The catheter tip must face upstream. 2. The catheter tip must face downstream. 3. The transducer must be higher than the catheter tip. 4. The transducer must be level with the catheter tip. a. 1 and 3 only b. 1 and 4 only c. 2 and 3 only d. 2 and 4 only ANS: B
When a catheter faces the source of blood flow it is “looking” upstream. An arterial line placed in the radial artery needs to face the blood flow to accurately measure pressures that are a result of left heart work. If the catheter faces downstream it reads the pressures ahead of it. To accurately measure pressure, the transducer needs to be at the same height or level with the tip of the catheter. If the transducer is higher than the catheter tip the fluid will be flowing away from the transducer and will produce a reading lower than the actual pressure. 11. While checking an indwelling central venous pressure (CVP) catheter the respiratory therapist
observes that the transducer is at the epistatic line. The respiratory therapist should do which of the following at this time? a. Zero the pressure transducer. b. Raise the pressure transducer. c. Accept the CVP reading obtained. d. Recalibrate the pressure transducer.
ANS: C
The epistatic line is located at the mid-thoracic line. The central venous pressure (CVP) transducer needs to be placed at this line to accurately measure CVP. The epistatic line is located about 5 cm behind the angle of Louis. This is the place where the transducer must be zero-balanced. Since the transducer is at the epistatic line in this question the pressure measured will be accurate and should be accepted. 12. While attempting to draw blood from an indwelling arterial catheter, the respiratory therapist
notices a dampened waveform and has difficulty withdrawing blood for sampling. What should the respiratory therapist’s immediate action be? a. Flush the catheter. b. Remove the catheter. c. Reposition the catheter. d. Recalibrate the transducer. ANS: B
The presence of both a persistently dampened waveform and difficulty withdrawing blood indicates that there is a clot. To avoid any adverse effects the catheter should be removed. Flushing the catheter could cause the blood clot to move into the patient’s circulation and has the potential to cause an infarction in the brain, heart, or lungs. Repositioning the catheter will not remove the clot. Recalibrating the transducer will not remove the clot. 13. The respiratory therapist preparing to insert an arterial line in the right radial artery performs
an Allen test. The result of the Allen test is 20 s. The respiratory therapist should do which of the following? a. Insert the cannula into the right radial artery. b. Repeat the Allen test on the right hand. c. Perform an Allen test on the left hand. d. Recommend a surgical cutdown at the right radial site. ANS: C
The purpose of the Allen test is to assess the adequacy of the collateral circulation to the hand, specifically ulnar circulation. A positive Allen test is a refill time of 5–10 s. This patient has a negative Allen test (23 s). Therefore, ulnar collateral circulation is insufficient and the right radial artery of this patient must not be cannulated. Another site, the left radial, should be assessed for collateral circulation. 14. Which of the following is not a common complication of systemic artery catheterization? a. Phlebitis b. Ischemia c. Hematoma d. Hemorrhage ANS: A
Phlebitis is inflammation of a vein. Since the catheter in this situation is in an artery, phlebitis is not possible as a result of a system artery catheterization. Ischemia, hematoma, and hemorrhage are all complications of systemic artery catheterization. 15. Which of the following measurements can be used to estimate right ventricular preload? a. Cardiac output b. Central venous pressure
c. Pulmonary artery pressure d. Pulmonary artery occlusion pressure ANS: B
Central venous pressure (CVP) is used to estimate the right ventricular preload. Pulmonary artery occlusion pressure (PAOP) reflects the preload of the left ventricle. The pulmonary artery pressure is generated by the right ventricle ejecting blood into the pulmonary circulation, which acts as a resistance to the output from the right ventricle. The pulmonary artery pressure (PAP) is a measurement of right ventricular afterload. Cardiac output is the amount of blood that the heart pumps out each minute. 16. Absolute confirmation of placement of a central venous pressure catheter is done with which
of the following? Chest X-ray Checking the centimeter mark Ensuring appropriate waveform Drawing a blood sample through the catheter
a. b. c. d.
ANS: A
A chest X-ray is used most often to confirm the placement of the central venous pressure (CVP) catheter. Checking the centimeter mark may be deceiving because the catheter may be curling up inside a vessel. Ensuring the waveform is not always accurate because other values may be low enough to appear to be a CVP measurement. Due to arterial blood gas acid–base changes and oxygenation problems, the blood sample drawn may appear to be mixed venous, when in fact it is not. 17. Which of the following is not a complication that may occur during the insertion of a central
venous pressure line? a. Bleeding b. Infection c. Pneumothorax d. Vessel damage ANS: B
It usually takes several hours to days for an infection to develop, so infection would not occur during the insertion of the central venous pressure (CVP) catheter. Bleeding, pneumothorax, and vessel damage are all complications that may occur during the insertion of the catheter. 18. Which of the following are vessels that often require a surgical cutdown when used for
pulmonary artery catheter access? 1. Femoral vein 2. Subclavian vein 3. Internal jugular vein 4. Antecubital vein a. 1 and 2 only b. 1 and 4 only c. 2 and 4 only d. 2 and 3 only ANS: C
The subclavian, internal jugular, external jugular, femoral, or antecubital veins may be used for access for pulmonary artery catheters. A surgical cut-down is often necessary when the subclavian or antecubital veins are used. This is done so that the vein may be visualized directly to facilitate catheter entry. It is especially useful in cases of hypovolemic shock and trauma when peripheral cannulation is difficult or impossible. 19. During the introduction of a pulmonary artery catheter the waveform seen in the figure is
visible on the monitor. This waveform represents which of the following locations?
a. b. c. d.
Right atrium Right ventricle Pulmonary artery Pulmonary capillary
ANS: A
This figure shows a pressure range of 2–6 mm Hg which is consistent with the right atrium. It also shows the characteristic respiratory fluctuations. The systolic pressure for the right ventricle is as high as 25 mm Hg, which is not seen in the figure. The systolic and diastolic ranges for pulmonary artery pressure are 15–35 and 5–15 mm Hg, respectively. This is higher than what is shown in the figure. Pulmonary capillary pressure when wedged is usually between 5 and 12 mm Hg, which is somewhat higher than what is shown in the figure. 20. During the insertion of a pulmonary artery catheter, the balloon needs to be inflated with air
when it enters which of the following? Right atrium Right ventricle Pulmonary artery Intrathoracic vessel
a. b. c. d.
ANS: D
The balloon must be inflated as soon as it enters the intrathoracic vessel so that the catheter may be flow-directed by the balloon through the blood into the right atrium, right ventricle, and pulmonary artery. The inflation of the balloon also protects the heart from endocardial and pulmonary artery damage and ventricular arrhythmias. 21. Which of the following include the most appropriate insertion sites for a pulmonary catheter
in a patient with phlebitis? 1. Internal jugular vein 2. Subclavian vein 3. Antecubital vein 4. Femoral vein
a. b. c. d.
2 and 4 only 1 and 2 only 3 and 4 only 1, 2, and 3 only
ANS: B
The reason the antecubital and femoral veins are not appropriate for the insertion for this patient is because one of the common problems associated with these sites is phlebitis. Using either of these sites in a patient who already has phlebitis would put the patient at risk for worsening the patient’s condition. 22. Which of the following can occur with excessive pulmonary artery catheter movement? a. Catheter whip b. Balloon rupture c. Catheter knotting d. Dampened waveform ANS: C
Excessive catheter movement can cause catheter knotting. Catheter whip is caused by high cardiac output or abnormal vessel diameter. Balloon rupture is due to loss of balloon elasticity or overinflation. Dampening of the waveform can be caused by air in line, a clot in the system, kinks in line, a catheter tip against the vessel wall, over-wedging, or blood on the transducer. 23. The waveform of a pulmonary catheter, shown in the figure, is located in which of the
following?
a. b. c. d.
Right atrium Pulmonary artery Right ventricle Pulmonary capillary with a wedge
ANS: B
The figure shows a systolic pressure of approximately 22 mm Hg and a diastolic of approximately 8–10 mm Hg. This falls within the normal pulmonary artery pressures of . The presence of the dicrotic notch is another hint that the catheter is in the pulmonary artery. The right atrial pressure is normally between 2 and 6 mm Hg. A catheter in the right ventricle would show pressures of . The pulmonary capillary wedge pressure (PCWP or PAOP) normally varies between 2 and 15 mm Hg. 24. A pulmonary artery catheter must be wedged in which of the following locations? a. Zone 1 b. Zone 2 c. Zone 3 d. Doesn’t matter ANS: C
To be accurate, the pulmonary artery catheter must be wedged in zone 3 of the lungs. In zone 3 there is a continuous column of blood between the catheter tip and the left atrium. In zones 1 and 2, the pulmonary vessels may be partly or completely compressed by adjacent pulmonary alveolar pressures. 25. Which of the following is the range for the time a pulmonary artery catheter should be
inflated? 5–10 s 15–30 s 30–60 s 60–120 s
a. b. c. d.
ANS: B
Fifteen to thirty seconds will allow enough time to stabilize the reading and avoid balloon rupture or pulmonary infarction. 26. Calculate the arterial oxygen content for a patient with the following arterial blood gas
measurements: Hgb = 9 g%, arterial oxygen saturation (SaO2) = 96%, arterial partial pressure of oxygen (PaO2) = 97 mm Hg. a. 8.6 vol% b. 11.0 vol% c. 11.9 vol% d. 12.1 vol% ANS: C
27. Calculate the arterial oxygen content for a patient with the following arterial blood gas
measurements: Hgb = 17 g%, arterial oxygen saturation (SaO2) = 93%, arterial partial pressure of oxygen (PaO2) = 64 mm Hg. a. 10.6 vol% b. 14.6 vol% c. 16.2 vol% d. 21.4 vol% ANS: D
28. A patient with an oxygen consumption of 340 mL/min, arterial oxygen content of 17.3 vol%,
and mixed venous oxygen content of 12.8 vol% has a cardiac output of which of the following? a. 2 mL/min b. 2.6 mL/min c. 7.6 mL/min d. 11 mL/min ANS: C
29. Calculate cardiac output using the Fick principle for the following values:
Oxygen consumption Arterial oxygen content Mixed venous oxygen content a. b. c. d.
280 mL/min 19.5 vol% 12 vol%
2.1 L/min 3.7 L/min 7.5 L/min 20.5 L/min
ANS: B
30. A patient with the hemodynamic values below has a cardiac output of which of the
following? Oxygen consumption Arterial oxygen content Mixed venous oxygen content a. b. c. d.
380 mL/min 23.2 vol% 10.3 vol%
2.9 mL/min 3.4 mL/min 12.9 mL/min 24.1 mL/min
ANS: A
31. Calculate the cardiac index using the following data:
Cardiac output = 4.6 L/min Body surface area = 1.2 m2 a. 0.26 m2/L/min b. 3.8 L/min/m2 c. 5.5 L/min-m2 d. 5.8 m2/L/min ANS: B
32. Calculate a 90-kg patient’s cardiac index with the following measurements: cardiac output 3.8
L/min, body surface area 3 m2. a. 0.79 m2/L/min b. 0.9 L/min/m2 c. 1.3 L/min/m2 d. 6.9 m2/L/min ANS: C 33. Calculate the cardiac index for a patient with the following data: heart rate = 80 beats/min,
stroke volume = 55 mL, and body surface area = 2.8 m2. a. 0.57 L/min/m2 b. 1.6 L/min/m2 c. 7.2 L/min/m2 d. 19.6 L/min/m2 ANS: A
Cardiac index (CI) = cardiac output (C.O.)/body surface area (BSA) and cardiac output (C.O.) = stroke volume (SV) heart rate (HR). 34. Calculate the stroke index using the following data: cardiac output = 3.7 L/min, heart rate =
90 beats/min, and body surface area = 1.7 m2. a. 0.024 mL/m2 b. 0.41 mL/m2 c. 24 mL/m2 d. 41 mL/m2 ANS: C
Stroke volume (SV) = cardiac output (C.O.)/heart rate (HR) and stroke index (SI) = stroke volume (SV)/body surface area (BSA). 35. Calculate the stroke volume (SV) and the stroke volume index (SI) using the following
information: cardiac output = 4.5 L/min, heart rate = 110 beats/min, and body surface area = 1.3 m2. a. SV = 41 mL; SI = 31.5 mL/m2 b. SV = 45 mL; SI = 34.3 mL/m2 c. SV = 46 mL; SI = 36 mL/m2 d. SV = 49.5 mL; SI = 38 mL/m2 ANS: A
Stroke volume (SV) = cardiac output (C.O.)/heart rate (HR) and stroke index (SI) = stroke volume (SV)/body surface area (BSA) 36. If the heart rate is 80 beats/min, how long is one beat? a. 0.75 s b. 0.9 s c. 1 s d. 1.3 s ANS: D
Cardiac cycle time = heart rate (HR)/60
37. Calculate the left ventricular stroke work for a patient with a body surface area of 1.1
m2, blood pressure 105/68 mm Hg, heart rate 86 beats/min, and cardiac output of 4.3 L/min. a. 10.9 g-m/m2 b. 35.6 g-m/m2 c. 49.5 g-m/m2 d. 54.4 g-m/m2 ANS: C
38. The hemodynamic values for a patient in the cardiovascular care unit are: blood pressure (BP)
96/60 mm Hg, pulmonary artery pressure (PAP) 29 mm Hg, pulmonary capillary wedge pressure (PCWP) 14 mm Hg, stroke volume (SV) 50 mL. The patient has a body surface area of 1.6 m2. Calculate the patient’s left ventricular stroke work (LVSW). a. 12.3 g-m/m2 b. 30.6 g-m/m2 c. 33.2 g-m/m2 d. 49 g-m/m2 ANS: B
39. Calculate the right ventricular stroke work (RVSW) given the following patient data:
pulmonary artery pressure (PAP) = 35/25 mm Hg, cardiac output (C.O.) = 3.6 L/min, heart rate (HR) = 107 beats/min, and body surface area (BSA) is 1.6 m2. a. 1.7 g-m/m2 b. 6.2 g-m/m2 c. 7.1 g-m/m2 d. 30.5 g-m/m2 ANS: B 40. Calculate the right ventricular stroke work (RVSW) for a patient with the following
measurements: pulmonary artery pressure (PAP) 50/32 mm Hg, cardiac output (C.O.) 4.0 L/min, heart rate (HR) 127/min, and body surface area (BSA) 1.72 m2. a. 0.11 g-m/m2 b. 4.5 g-m/m2 c. 9.5 g-m/m2 d. 10.2 g-m/m2 ANS: C
41. The following hemodynamic measurements were obtained from a patient in the intensive care
unit: pulmonary artery pressure (PAP) = 67/25 mm Hg, pulmonary artery occlusion pressure (PAOP) = 18 mm Hg, blood pressure (BP) = 100/50 mm Hg, central venous pressure (CVP) = 17 mm Hg, cardiac output (C.O.) = 5.7 L/min, and heart rate (HR) = 75 beats/min. Calculate this patient’s pulmonary vascular resistance (PVR).
a. b. c. d. ANS: A
42. Calculate the pulmonary vascular resistance (PVR) given the following measurements
obtained during a hemodynamic study: pulmonary artery pressure (PAP) = 40/22 mm Hg, pulmonary artery occlusion pressure (PAOP) = 12 mm Hg, blood pressure (BP) = 156/80 mm Hg, central venous pressure (CVP) = 19 mm Hg, cardiac output (C.O.) = 4.8 L/min, and heart rate (HR) = 68 beats/min. a. b. c. d. ANS: B
43. The following hemodynamic measurements were obtained from a patient in the intensive care
unit: pulmonary artery pressure (PAP) = 67/25 mm Hg, pulmonary artery occlusion pressure (PAOP) = 18 mm Hg, blood pressure (BP) = 100/50 mm Hg, central venous pressure (CVP) = 17 mm Hg, cardiac output (C.O.) = 5.7 L/min, and heart rate (HR) = 75 beats/min. Calculate this patient’s systemic vascular resistance (SVR). a. b. c. d. ANS: D
44. Calculate the systemic vascular resistance (SVR) given the following measurements obtained
during a hemodynamic study: pulmonary artery pressure (PAP) = 40/22 mm Hg, pulmonary artery occlusion pressure (PAOP) = 12 mm Hg, blood pressure (BP) = 156/80 mm Hg, central venous pressure (CVP) = 19 mm Hg, cardiac output (C.O.) = 4.8 L/min, and heart rate (HR) = 68 beats/min. a. b. c. d. ANS: D
45. A patient with a mitral valve stenosis is most likely to have which of the following pulmonary
artery occlusion pressure (PAOP) values? 4 mm Hg 6 mm Hg 12 mm Hg 20 mm Hg
a. b. c. d.
ANS: D
The normal range for pulmonary artery occlusion pressure (PAOP) is 5–12 mm Hg. Mitral valve stenosis is the cause of an abnormally high PAOP. Therefore the value of 20 mm Hg is the correct answer. 46. Which of the following is the hemodynamic measurement that is indicative of a patient with
right heart failure? Pulmonary artery occlusion pressure (PAOP) = 12 mm Hg Central venous pressure (CVP) = 16 mm Hg Pulmonary artery pressure (PAP) = 35/15 mm Hg Mean arterial pressure (MAP) = 80 mm Hg
a. b. c. d.
ANS: B
The normal range for pulmonary artery occlusion pressure (PAOP) is 5–12 mm Hg, for central venous pressure (CVP) 2–6 mm Hg, for pulmonary artery pressure (PAP) 15–35/5–15 mm Hg, and for mean arterial pressure (MAP) 70–100 mm Hg. Right heart failure causes the CVP to increase significantly. Answer B shows a CVP that is greatly increased and is therefore indicative of right heart failure. 47. Which of the following disorders can cause an increase in systemic vascular resistance? a. Lung collapse b. Hypervolemia c. Chronic bronchitis d. Cardiogenic pulmonary edema ANS: B
Chronic obstructive pulmonary disease (COPD) does not, in and of itself, cause an increase in systemic vascular resistance. Cardiogenic pulmonary edema and lung collapse will decrease systemic vascular resistance. Hypovolemia will cause an increase in systemic vascular resistance due to stimulation of the baroreceptor reflex. 48. Which of the following hemodynamic parameter that is not within normal limits? a. Cardiac index (CI) = 4 L/min/m2 b. Mixed venous oxygen content (CO2) = 10 vol% c. Mean arterial pressure (MAP) = 18 mm Hg d. Pulmonary vascular resistance (PVR) = 200 dyne s cm–5 ANS: C
The normal values for the hemodynamic parameters in this question are: Cardiac index (CI) = 2.5–4 L/min/m2, mixed venous oxygen content (CO2) = 15 vol%, mean arterial pressure (MPAP) = 10–20 mm Hg, and pulmonary vascular resistance . The value that is not within normal limits is the CO2.
49. A high cardiac output can cause which of the following complications with a pulmonary
artery catheter? Pneumothorax Catheter whip Pulmonary infarction Catheter knotting
a. b. c. d.
ANS: B
All of the answers are complications associated with pulmonary artery catheters. However, catheter whip or fling is the only one associated with a high cardiac output. 50. Advancing a pulmonary artery catheter into a smaller artery may cause which of the following
complications? Pneumothorax Air embolism Pulmonary infarction Ventricular fibrillation
a. b. c. d.
ANS: C
A pneumothorax may be caused during the insertion procedure. An air embolism may be caused by the rupture of the balloon if overinflated or during insertion. A pulmonary infarction may be caused by the catheter being advanced into a smaller artery or by overinflation of the balloon, prolonged wedging, or clot formation. Ventricular fibrillation would most likely be caused during the insertion process when the endocardium is irritated by the catheter while it is passing through the heart. 51. During the inspiratory phase of spontaneous breathing, what happens to the pulmonary artery
(PA) waveform? a. There is no change in the waveform. b. The PA waveform trend increases. c. The PA waveform trend decreases. d. The PA diastolic pressure increases. ANS: C
With spontaneous breathing, the intrapleural pressure decreases during inspiration, causing the pulmonary artery (PA) wave pattern to descend. Conversely, with spontaneous expiration, intrapleural pressure increases, and the wave rises. 52. An intubated patient with no known history of congestive heart failure is in the ICU. The
patient is comatose and currently receiving mechanical ventilation via volume-controlled continuous mandatory ventilation (VC-CMV), set rate 12 breaths/min, set tidal volume (VT) 400 mL, positive end-expiratory pressure (PEEP) 18 cm H2O, fractional inspired oxygen (FIO2) 0.35, and the patient is not assisting. Hemodynamic measurements show the following: central venous pressure (CVP) 5 mm Hg, pulmonary artery pressure (PAP) 33/20 mm Hg, and pulmonary artery occlusion pressure (PAOP) 16 mm Hg. Arterial blood gas (ABG) results are: pH 7.43, arterial partial pressure of carbon dioxide (PaCO2) 38 mm Hg, arterial partial pressure of oxygen (PaO2) 90 mm Hg. The physician asks for recommendations to improve this patient’s hemodynamics. The most appropriate recommendation for this patient is which of the following? a. Initiate pressure support ventilation (PSV) 10 cm H2O with CPAP 10 cm H2O, and check cardiac output.
b. Decrease the PEEP incrementally and recheck hemodynamic measurements. c. Change to volume-controlled synchronized intermittent mandatory ventilation
(VC-SIMV) with the same settings, and recheck hemodynamic measurements. d. Change to pressure-controlled continuous mandatory ventilation (PC-CMV), peak
inspiratory pressure (PIP) 25 cm H2O, PEEP 18 cm H2O, FIO2 0.35, and check PAP. ANS: B
The patient’s central venous pressure (CVP) is within normal limits. The pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) are both elevated. These hemodynamic results are consistent with left ventricular failure. However, when looking at the ventilator settings it should be noted that the set positive end-expiratory pressure (PEEP) is >15 cm H2O. This setting will prolong changes in lung zones and produce erroneously elevated pressure readings by squeezing the pulmonary vessels and overinflating the lungs. Changing the mode to pressure support ventilation (PSV) or synchronized intermittent mandatory ventilation (SIMV) will lower the mean inspiratory pressures and minimize the hemodynamic effects of positive intrathoracic pressure. However, this patient is comatose so PSV is not an option (choice “A”) and changing to volume-controlled synchronized intermittent mandatory ventilation (VC-SIMV) with the same PEEP level (choice “C”) will have little effect on the hemodynamics. Pressure ventilation (choice “D”) will have about the same effect on the patient’s hemodynamic values as the current settings. Decreasing the PEEP incrementally and checking the hemodynamic measurements can be used to optimize the PEEP level for this patient. 53. A patient in the ICU has a chest X-ray that shows bilateral infiltrates and has the following
hemodynamic measurements: central venous pressure (CVP) 5 mm Hg, pulmonary artery pressure (PAP) 24/13 mm Hg, and pulmonary artery occlusion pressure (PAOP) 21 mm Hg. These findings are consistent with which of the following? a. Pulmonary hypertension b. Right ventricular failure c. Noncardiogenic pulmonary edema d. Cardiogenic pulmonary edema ANS: D
The central venous pressure (CVP) and pulmonary artery pressure (PAP) are both within normal limits. Therefore, there is no pulmonary hypertension and no right ventricular failure. The elevated pulmonary artery occlusion pressure (PAOP) along with the bilateral infiltrates is consistent with cardiogenic pulmonary edema due to left ventricular failure. Noncardiogenic pulmonary edema would not cause an elevated PAOP. 54. A patient in the ICU has a chest X-ray that shows bilateral infiltrates and has the following
hemodynamic measurements: central venous pressure (CVP) 3 mm Hg, pulmonary artery pressure (PAP) 21/10 mm Hg, and pulmonary artery occlusion pressure (PAOP) 8 mm Hg. These findings are consistent with which of the following? a. Acute respiratory distress syndrome b. Cardiogenic pulmonary edema c. Pulmonary hypertension d. Right heart failure ANS: A
The central venous pressure (CVP) and pulmonary artery pressure (PAP) are both within normal limits. Therefore, there is no pulmonary hypertension and no right ventricular failure. The bilateral infiltrates with a normal pulmonary artery occlusion pressure (PAOP) do not suggest cardiogenic pulmonary edema but are indicative of acute respiratory distress syndrome (ARDS). 55. Ventricular contractility can be estimated by which of the following? a. Systemic vascular resistance b. Ejection fraction c. Pulmonary vascular resistance d. Left ventricular stroke work ANS: B
The ejection fraction is a derived variable that provides an estimate of ventricular contractility. The systemic vascular resistance is an indicator of left ventricular afterload. Pulmonary vascular resistance indicates right ventricular afterload. Left ventricular stroke work reflects the pressure generated by the heart during a ventricular contraction. 56. Which of the following can cause an elevated right arterial pressure? a. Cardiac tamponade b. Third-degree heart block c. Decreased ventricular compliance d. Left ventricular failure ANS: A
BOX 11-3 Causes of Abnormal Right Atrial and Pulmonary Artery Occlusion Pressure (PAOP) Values and Patterns Abnormal Values Abnormal Patterns Elevated Right Atrial Pressure (RAP) Large a Waves Volume overload Tricuspid/mitral stenosis Right ventricular (RV) failure Decreased ventricular compliance Tricuspid stenosis or regurgitation Compliance Cardiac tamponade Loss of atrioventricular synchrony Constrictive pericarditis Third-degree block Chronic left ventricular (LV) failure Any other electrical dissociation Elevated Pulmonary Artery Occlusion Pressure Absent a Waves (PAOP) Atrial fibrillation Volume overload Atrial flutter Left ventricle failure Junctional rhythms Mitral stenosis or regurgitation Paced rhythms Cardiac tamponade Ventricular rhythms Constrictive pericarditis High PEEP Low RAP or PAOP Hypovolemia 57. Which of the following can cause a low pulmonary artery occlusion pressure? a. Constrictive pericarditis b. High PEEP c. Hypovolemia
d. Cardiac tamponade ANS: C
BOX 11-3 Causes of Abnormal Right Atrial and Pulmonary Artery Occlusion Pressure (PAOP) Values and Patterns Abnormal Values Abnormal Patterns Elevated Right Atrial Pressure (RAP) Large a Waves Volume overload Tricuspid/mitral stenosis Right ventricular (RV) failure Decreased ventricular compliance Tricuspid stenosis or regurgitation Compliance Cardiac tamponade Loss of atrioventricular synchrony Constrictive pericarditis Third-degree block Chronic left ventricular (LV) failure Any other electrical dissociation Elevated Pulmonary Artery Occlusion Pressure Absent a Waves (PAOP) Atrial fibrillation Volume overload Atrial flutter Left ventricle failure Junctional rhythms Mitral stenosis or regurgitation Paced rhythms Cardiac tamponade Ventricular rhythms Constrictive pericarditis High PEEP Low RAP or PAOP Hypovolemia
Chapter 12: Methods to Improve Ventilation in Patient-Ventilator Management Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. During mechanical ventilation of a patient with COPD, the PaCO2 = 58 mm Hg and the minute
ventilation = 5.5 L/min. The desired PaCO2 for this patient is 45 mm Hg. To what should the minute ventilation be changed? a. 4.3 L/min b. 4.8 L/min c. 6.6 L/min d. 7.1 L/min ANS: D
Desired VT = Known P CO2 · Known VT/Desired P CO2 2. A patient with CHF is being mechanically ventilated. The patient’s current PaCO2 = 28 mm
Hg, and the ventilator set rate is 16 per minute. The desired PaCO2 for this patient is 40 mm Hg. To what should the set rate be changed? a. 7/min b. 11/min c. 14/min d. 18/min ANS: B
Desired f = Known PaCO2 · Known f/Desired PaCO2 3. A patient with pneumonia and underlying COPD is being mechanically ventilated in the VC-
CMV mode with VT 650 mL. The resulting PaCO2 is 62 mm Hg. What change should be made to the VT to obtain a desired PaCO2 of 50 mm Hg for this patient? a. 400 mL b. 800 mL c. 1000 mL d. 1200 mL ANS: B
Desired VT = Known PaCO2 · Known VT/Desired PaCO2 4. The average tidal volume range in an individual with no pulmonary problems is which of the
following? 4–5 mL/kg IBW 5–8 mL/kg IBW 8–10 mL/kg IBW 12–15 mL/kg IBW
a. b. c. d.
ANS: B
Recommended guidelines are to target the VT to 5–8 mL/kg ideal body weight (IBW) while ensuring that the plateau pressure (Pplat) is maintained at less than 30 cm H2O.
5. A male patient (76-kg IBW) with no history of pulmonary disease is brought to the emergency
department for treatment of a drug overdose. He is intubated and placed on mechanical ventilation with VC-CMV, f = 12/min, VT = 450 mL. The resulting arterial blood gas values are: pH 7.32, PaCO2 53 mm Hg, and HCO 25 mEq/L. The most appropriate action to correct the acid–base disturbance is which of the following? a. Increase VT to 595 mL. b. Increase VT to 760 mL. c. Increase frequency to 16/min. d. Decrease frequency to 10/min. ANS: A
Desired VT = Known PaCO2 · Known VT/Desired PaCO2 The desired target for VT for this patient is 5–8 mL/kg IBW. Because the set VT of 450 mL is at 5.9 mL/kg, there is room to increase the VT. After calculating the desired VT using the formula, the new volume is at 7.8 mL/kg. A VT of 760 mL would be at 10 mL/kg IBW. 6. A female patient (59-kg IBW) with no history of pulmonary disease is being invasively
ventilated with VC-CMV, f = 12/min, VT = 470 mL, PEEP = 5 cm H2O, FIO2 = 0.5. ABG results with these settings are: pH 7.31, PaCO2 54 mm Hg, PaO2 92 mm Hg, SaO2 90%, HCO 24 mEq/L. The most appropriate action for the respiratory therapist to take is which of the following? a. Increase f to 16/min. b. Increase VT to 635 mL. c. Decrease VT to 400 mL. d. Decrease PEEP to 3 cm H2O. ANS: A
The target VT for an individual without pulmonary disease is 5–8 mL/kg IBW. This patient’s VT range is 295–472 mL, meaning that the upper limit of this range has been reached. The f should be changed to increase this patient’s minute ventilation. Desired f = Known PaCO2 · Known f/Desired PaCO2; desired f = 16 7. A male patient (74-kg IBW) is being ventilated with PC-CMV, f = 12/min, PIP = 20 cm H2O,
TI = 1.5 s; the resulting flow–time scalar is shown below. The patient’s measured VT is 435 mL. ABG results on these settings are: pH 7.32, PaCO2 54 mm Hg, HCO 25 mEq/L. The most appropriate action to take is which of the following?
a. Increase f to 16/min. b. Increase TI to 2.5 s.
c. Increase PIP to 27 cm H2O. d. Decrease flow rate to 40 L/min. ANS: C
The flow–time scalar shows that TI is adequate, because it shows a time of zero flow during inspiration. Therefore, changing TI would not be appropriate. The measured VT for this patient is at 5.9 mL/kg IBW; therefore, the VT could be increased. In the PC mode, this would be done with by increasing the set PIP using the following formulas: Desired VT = Known PaCO2 · Known VT/Desired PaCO2; approximately 590 mL Desired P = 26.8 cm H2O 8. A 28-year-old female (55-kg IBW) is being mechanically ventilated with VC-CMV, f =
14/min, VT = 700 mL. The patient has no history of pulmonary disease. The resulting ABG values are: pH 7.55, PaCO2 27 mm Hg, HCO 23 mEq/L. The most appropriate action to take is which of the following? a. Decrease VT to 600 mL. b. Decrease VT to 450 mL. c. Decrease f to 12/min. d. Decrease f to 10/min. ANS: B
The original volume setting exceeded the maximum VT for this patient. The VT should be set between 275 and 440 mL to achieve 5–8 mL/kg IBW. Therefore, the VT must be reduced to avoid overdistention. Using the formula: Desired VT = Known PaCO2 · Known VT/Desired PaCO2 Desired VT = 473 mL The VT of 450 mL is closest to the desired VT and is more in line with the acceptable range. 9. A male patient (83-kg IBW) is intubated and ventilated with PC-CMV, f = 12/min, set PIP =
28 cm H2O, resulting in a VT of 430 mL. The ABG results on this setting are: pH 7.35, PaCO2 45 mm Hg, and HCO 23 mEq/L. Forty-eight hours later on the same settings, the ABG results are: pH 7.54, PaCO2 27 mm Hg, and HCO 21 mEq/L with an exhaled VT of 800 mL. The most appropriate action at this time is which of the following? a. Decrease PIP to 25 cm H2O. b. Decrease PIP to 19 cm H2O. c. Decrease f to 10/min. d. Decrease f to 8/min. ANS: B
At first the patient responded appropriately to the PC-CMV settings. At that point the Cs was 15 mL/cm H2O. After 48 hours, the patient’s lungs improved and the same pressure, 28 cm H2O, resulted in a VT of 800 mL. The patient’s Cs now is 28.5 mL/cm H2O, and the combination of Cs and PIP is resulting in respiratory alkalosis. The acceptable VT range for this patient is 415–664 mL (5–8 mL/kg IBW). Because the exhaled tidal volume now exceeds this range, the volume needs to be reduced. This is accomplished by reducing the set PIP using the following formulas:
Desired VT = and set PIP = VT/CS = 19 cm H2O. 10. A patient with an IBW of 68 kg is intubated and being mechanically ventilated with VC-CMV,
f = 12/min, and VT = 470 mL. The patient has a combined respiratory rate of 25/min. The ABG results are: pH 7.56, PaCO2 26 mm Hg, and HCO 22 mEq/L. The most appropriate action is to do which of the following? a. Decrease the set f to 8/min. b. Decrease the set VT to 300 mL. c. Sedate and paralyze the patient. d. Change the mode to VC-IMV. ANS: D
The patient has ventilator-induced respiratory alkalosis, because the patient is triggering the machine breaths each time there is a spontaneous effort. Decreasing the set f will not alter the rate at which the patient is assisting. Decreasing the set VT to 300 mL will most likely result in the patient’s breathing at a faster rate because of the low volume. The patient could be sedated and paralyzed. However, the patient is not demonstrating a need for this option (i.e., extreme agitation, increased WOB, and patient-ventilator asynchrony). Changing to the VC-SIMV mode will allow the patient to breathe spontaneously and not trigger a machine breath each time. 11. Which of the following can cause metabolic acidosis? a. Overdose with salicylate b. Diuretic administration c. Nasogastric suctioning d. Lactate administration ANS: A
Ingestion of salicylate causes the production of acid, resulting in metabolic acidosis. 12. Which of the following can cause metabolic alkalosis? a. Renal failure b. Potassium deficiency c. Carbonic anhydrase inhibitors d. Ethylene glycol ANS: B
Potassium deficiency causes acid to shift into the cells, reducing the amount of acid in the blood. 13. If respiratory acidosis persists after alveolar ventilation of a patient has been increased, which
of the following could be the cause? Chronic obstructive pulmonary disease Pulmonary embolism Pulmonary edema Low PEEP levels
a. b. c. d.
ANS: B
If pure respiratory acidosis persists even after alveolar ventilation has been increased, the patient may have a problem with increased dead space. One cause of increased dead space is a pulmonary embolism or low cardiac output, resulting in low pulmonary perfusion.
14. A 59-kg IBW female patient is being mechanically ventilated in the CMV mode, f = 12/min,
VT = 400 mL, PEEP = 5 cm H2O, FIO2 = 0.5. The ABG results on these settings show a respiratory acidosis and severe hypoxemia. The respiratory therapist increases the set VT and increases the PEEP to 12 cm H2O. The resulting ABGs show improved oxygenation, but the patient still has a respiratory acidosis. The respiratory acidosis may be due to which of the following? a. Tissue hypoxia b. Increased dead space c. Increased cardiac output d. Continued hypoventilation ANS: B
If an increase in alveolar ventilation does not correct a respiratory acidosis, the condition is usually caused by pulmonary embolism, low pulmonary perfusion, or increased dead space. The reduction in pulmonary blood flow caused by high alveolar pressures can increase dead space. In this patient’s case, the increase in PEEP is most likely the reason for the continued respiratory acidosis. 15. A patient diagnosed with sepsis who is being mechanically ventilated has a combined minute
ventilation of 25 L/min with a PaCO2 of 38 mm Hg. The reason for these findings is most likely which of the following? & CO 1. Increased V 2 & 2. Decreased V CO2 3. Increased VD/VT 4. Decreased VD/VT a. 1 and 3 only b. 1 and 4 only c. 2 and 3 only d. 2 and 4 only ANS: A
& CO are elevated in patients who have fever, burns, multiple trauma, Metabolic rate and V 2 sepsis, hyperthyroidism, muscle tremors or seizures, agitation, and in those patients who have & undergone multiple surgical procedures. Regardless of the cause, it is clear that VE will be increased and WOB will be elevated. Increasing the ventilator rate will decrease the patient’s WOB, but auto-PEEP may occur. If auto-PEEP is a factor, it may be beneficial to add enough pressure support (PS) for the spontaneous breaths to reduce WOB through the ET and circuit. Other options might include switching to PC-CMV and using sedation to reduce the patient’s work. 16. In which of the following situations might iatrogenic hyperventilation be considered? a. Severe traumatic brain injury b. Initial treatment for increased intracranial pressure c. Acute head injuries with increased intracranial pressure d. Acute neurological deterioration with increased intracranial pressure ANS: D
Historically, iatrogenic hyperventilation has been used in patients with acute head injury and increased intracranial pressure (ICP). Hyperventilation lowers CO2 in the blood, which in turn is associated with constriction of cerebral blood vessels, resulting in a reduction in blood flow to the brain. Although this approach was believed by many clinicians to help lower increased ICP, therapeutic guidelines for head injuries with increased ICP do not recommend prophylactic hyperventilation (PaCO2 <25 mm Hg) during the first 24 hours. Hyperventilation during the first few days following severe traumatic brain injury may actually increase cerebral ischemia and cause cerebral hypoxemia. Hyperventilation may be required for brief periods when acute neurological deterioration is present and ICP is elevated. 17. Permissive hypercapnia could benefit patients with which of the following? a. Cerebral trauma b. Intracranial lesion c. Acute lung injury d. Cardiovascular instability ANS: C
Patients with ALI benefit from permissive hypercapnia to protect the lungs from ventilatorinduced lung injury. Contraindications to PHY include cerebral disorders, because CO2 is a powerful vasodilator. PHY is also contraindicated in patients with preexisting cardiovascular instability, because the circulatory effects of PHY can include decreased myocardial contractility, arrhythmias, vasodilation, and increased sympathetic activity. 18. A 45-year-old female (58-kg IBW) with a past medical history of asthma arrives at the
emergency department short of breath, anxious, diaphoretic, and unable to perform a peak expiratory flow measurement. She also has a combined acidosis. Breath sounds reveal the patient is not moving much air. The patient is intubated, stabilized, and transported to the ICU. The ventilator settings are: PC-CMV, f = 12/min, PIP = 30 cm H2O, FIO2 = 0.6, and PEEP = 3 cm H2O. The patient is sedated and paralyzed; the resulting ABGs are: pH 7.17, PaCO2 69.3 mm Hg, PaO2 90 mm Hg, and HCO 21 mEq/L after continuous bronchodilator therapy. The respiratory rate is increased to 20/min, and the next ABG results are: pH 7.26, PaCO2 58 mm Hg, PaO2 96 mm Hg, and HCO 22 mEq/L. The respiratory therapist should suggest which of the following at this time? a. Increase PIP to 38 cm H2O. b. Decrease PIP to 25 cm H2O. c. Continue with current therapy. d. Change to VC-CMV, f = 12/min, VT = 700 mL. ANS: C
The current therapy should be continued in an effort to prevent lung injury. 19. At what point during deep suctioning should negative pressure be applied? a. Five seconds after resistance is met b. Ten seconds after insertion of the catheter c. After 1-cm withdrawal from the point of resistance d. After 2-cm withdrawal from the point of resistance ANS: C
During deep suctioning, once resistance is met, the catheter is withdrawn approximately 1 cm before negative pressure is applied.
20. A suction catheter long enough to reach a main-stem bronchus should be what length? a. 22 cm (8.7 inches) b. 25 cm (9.8 inches) c. 46 cm (18 inches) d. 56 cm (22 inches) ANS: D
A catheter of about 56 cm (22 inches) should be long enough to reach a main-stem bronchus. 21. What size suction catheter is appropriate for use in a patient with a 7-mm ET tube? a. 8 Fr b. 10 Fr c. 12 Fr d. 14 Fr ANS: B
Multiply the ET tube size by 3; this converts the ET size to French units (Fr). Then divide the result by 2, for a size that is half or less of the ET diameter. 22. Advantages of closed suctioning include which of the following?
1. No need to prehyperoxygenate or posthyperoxygenate 2. No need to prehyperventilate or posthyperventilate 3. Decreased risk for infection for caregiver 4. No loss of PEEP during the procedure a. 1 and 2 only b. 3 and 4 only c. 1, 2, and 4 only d. 2, 3, and 4 only ANS: B 23. During a closed suctioning procedure, the patient’s heart rate changes from 95 to 58
beats/min. The respiratory therapist should take what immediate action? a. Continue the procedure until secretions are removed. b. Stop the procedure and switch to the open suctioning method. c. Stop the procedure and use the ventilator to hyperoxygenate the patient with 100%
oxygen. d. Remove the patient from the ventilator and ventilate the person with a resuscitator
bag. ANS: C
Cardiac arrhythmias can occur during aggressive suctioning. Bradycardia may occur when the catheter stimulates vagal receptors in the upper airways. The procedure should be stopped and the ventilator should be used to hyperoxygenate the patient. 24. Which of the following is recommended when administering aerosols to mechanically
ventilated patients with a small-volume nebulizer? a. Make sure the flow-by is turned on during administration. b. Keep the HME inline during the aerosol treatment. c. Use the ventilator nebulizer system when appropriate.
d. Bypass the humidifier during the aerosol treatment. ANS: C
Use the ventilator nebulizer system if it meets the SVN flow needs and cycles on inspiration. Flow-by should be turned off, because it produces a continuous flow through the circuit during exhalation while nebulization is proceeding. Remove the HME from the circuit, because it will trap the aerosol particles. Do not disconnect the humidifier. 25. When using an SVN or pMDI with NIV, where in the NIV circuit should the device be placed
to obtain the greatest aerosol deposition? a. Before the leak port b. Anywhere in the circuit c. Between the NIV and the humidifier d. Between the leak port and the face mask ANS: D
To achieve the greatest aerosol deposition when using a pMDI or SVN, the device should be placed close to the patient, between the leak port and the face mask. 26. Which of the following ventilator graphics could be used to assess the response to
bronchodilator therapy for a patient receiving mechanical ventilation with VC-CMV? 1. Pressure–time scalar 2. Flow–time scalar 3. Pressure–volume loop 4. Volume–time scalar a. 1 and 2 only b. 3 and 4 only c. 1 and 3 only d. 1, 2, and 4 only ANS: D
With VC-CMV, the volume–time scalar will remain constant. The expiratory portion of the flow–time scalar can show improvement if there is a response to the bronchodilator. The changes in PIP can be monitored with the pressure–time scalar and/or the pressure–volume loop. 27. A mechanically ventilated patient continues to have rhonchi after deep suctioning. The
respiratory therapist should recommend which of the following? Prone position Vest Airway Clearance System Prone position with the foot of the bed elevated 12 inches Supine position with the foot of the bed elevated 18 inches
a. b. c. d.
ANS: B
The Vest Airway Clearance System creates vibrations around the entire thorax, which helps mobilize secretions from all areas of the lungs. The prone position is used for patients with ARDS to assist with oxygenation and perfusion of the “good” lung areas. The head-down position may cause an increase in ICP or BP or may increase the risk for vomiting.
28. A physician and a respiratory therapist are performing bedside bronchoscopy of an invasively
ventilated patient. Fentanyl and midazolam were used for conscious sedation. After the bronchoscopy, the patient is not arousable. Which of the following should be done at this time? a. Draw a sample for arterial blood gas determinations. b. Increase the patient’s respiratory rate. c. Administer naloxone. d. Administer atropine. ANS: C
The patient requires reversal of the sedation. Naloxone or flumazenil may be used to reverse sedation. 29. An invasively ventilated patient with ARDS is on PC-CMV, PIP = 30 cm H2O, PEEP = 12 cm
H2O, FIO2 = 1.0. The patient’s returned VT is 320 mL. The ABG results on these settings are: pH 7.3, PaCO2 53 mm Hg, PaO2 62 mm Hg. The patient is placed in the prone position, and after 1 hour, ABG results show: pH 7.38, PaCO2 46 mm Hg, PaO2 83 mm Hg. The respiratory therapist should do which of the following? a. Keep the patient in the prone position. b. Place the patient in the supine position. c. Keep the patient in the prone position and decrease the FIO2. d. Place the patient in the supine position and decrease PEEP. ANS: C
This patient has shown a positive response to the prone position; therefore, the patient can be maintained in this position for 2–12 hours. A reduction in the FIO2 would be appropriate, because the level is at 1.0. 30. What effect does positive pressure ventilation have on fluid balance? a. It increases urinary output. b. It increases renal perfusion. c. It causes renal malfunction. d. It increases plasma ADH levels. ANS: D
Positive pressure ventilation increases the plasma antidiuretic hormone level. Renal malfunction does directly affect fluid balance, but it is not caused by PPV. PPV decreases urinary output because of the increased levels of ADH. PPV may also decrease renal perfusion. 31. Common causes of respiratory alkalosis include which of the following?
1. Mechanical ventilation 2. Anxiety 3. Hyperventilation 4. Parenchymal lung disease a. 1 and 2 only b. 3 and 4 only c. 1, 2, and 4 only d. 2, 3, and 4 only ANS: C
Common causes of respiratory alkalosis: Hypoxia with compensatory hyperventilation Parenchymal lung disease Medications Mechanical ventilation CNS disorders Anxiety Metabolic problems 32. Which of the following is the normal ratio of dead space–to-tidal volume (VD/VT)? a. 0.2–0.4 b. 0.4–0.6 c. 0.6–0.8 d. 0.8–1.0 ANS: A
The normal ratio of dead space-to-tidal volume (VD/VT) is 0.2–0.4. In critically ill patients, this value can be greater than 0.7.
Chapter 13: Improving Oxygenation and Management of Acute Respiratory Distress Syndrome Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. During mechanical ventilation of a patient with COPD, the PaO2 = 58 mm Hg and the FIO2 =
0.5. If the desired PaO2 is 65 mm Hg, the FIO2 needs to be changed to which of the following? 0.44 0.56 0.65 0.74
a. b. c. d.
ANS: B
2. During mechanical ventilation of a patient with CHF, the PaO2 = 38 mm Hg and the FIO2 =
0.6. If the desired PaO2 is 60 mm Hg, the FIO2 needs to be changed to which of the following? 0.65 0.75 0.85 0.95
a. b. c. d.
ANS: D
3. Thirty minutes after intubation and initiation of mechanical ventilation, a patient’s PaO2 = 55
mm Hg and the FIO2 = 0.5. To what should the FIO2 be set to obtain a PaO2 of 80 mm Hg? 0.65 0.75 0.85 0.95
a. b. c. d.
ANS: B
4. Calculate the pulmonary shunt fraction using the following data: Pb = 757 mm Hg;
hemoglobin (Hb) = 11 g/dL; FIO2 = 0.5; PaO2 = 86 mm Hg; PaCO2 = 40 mm Hg; SaO2 = 91%; = 40 mm Hg; = 71%; respiratory exchange quotient (R) = 0.8. a. 19% b. 23%
c. 26% d. 32% ANS: A
5. Calculate the pulmonary shunt fraction for a patient with the following data: Pb = 760 mm Hg;
Hb = 10 g/dL; respiratory quotient = 0.8; FIO2 = 0.6; PaO2 = 100 mm Hg; SaO2 = 93%; PaCO2 = 45 mm Hg; = 36 mm Hg; = 70%. a. 13% b. 26% c. 30% d. 41% ANS: B
6. Calculate the pulmonary shunt fraction for a patient with the following data: CAO2 = 17 vol%;
CaO2 = 16.5 vol%; = 11 vol%. 8% 15% 30% 37%
a. b. c. d.
ANS: A
7. PEEP therapy is indicated for patients with which of the following? a. PaO2 of 95 mm Hg while receiving an FIO2 of 0.3 b. PaO2 of 100 mm Hg while receiving an FIO2 of 0.8 c. Returned VT of 600 mL with a Pplat of 12 cm H2O d. Returned VT of 800 mL with a Pplat of 15 cm H2O ANS: B
The PaO2/FIO2 for answer “A” is 317, which shows no ARDS. The PaO2/FIO2 for answer “B” is 125; this is an indication for PEEP therapy (PaO2/FIO2 < 200 for ARDS). The compliance for answers “C” and “D” is 50 mL/cm H2O and 53 mL/cm H2O, respectively. These compliances are normal for intubated patients. 8. Which of the following patients may benefit from PEEP? a. COPD b. Asthma c. ARDS d. Cystic fibrosis
ANS: C
ARDS is a clinical disorder that benefits from the use of PEEP. The other three choices are obstructive lung diseases and will not benefit from the use of PEEP therapy. 9. How long after PEEP is increased should all ventilatory and available hemodynamic
parameters be measured and calculated? 5 minutes 15 minutes 25 minutes 40 minutes
a. b. c. d.
ANS: B
Approximately 15 minutes after an increase in PEEP, all ventilatory and available hemodynamic parameters are measured and calculated. 10. Assessing the outcome of PEEP at levels set above 15–20 cm H2O is best done using which of
the following? Static compliance measurements Pressure–volume loop graphics Pulmonary artery occlusion pressure Central venous pressure measurements
a. b. c. d.
ANS: C
At pressures above 15–20 cm H2O, the compliance measurement is not a good indicator of cardiovascular function, and monitoring of the pulmonary artery pressure may be indicated. 11. An absolute contraindication to PEEP is which of the following? a. Emphysema b. Bronchopleural fistula c. Untreated tension pneumothorax d. Elevated intracranial pressures ANS: C
An absolute contraindication to PEEP is a tension pneumothorax. PEEP must be used with care in patients with bronchopleural fistulas and elevated intracranial pressures. PEEP also must be used with care in patients with emphysema, because it may increase hyperinflation, which can lead to compression of adjacent capillaries. 12. The level of applied PEEP should be set at what point on the pressure–volume curve? a. At the upper inflection point of the inflation curve b. Above the lower inflection point of the deflation curve c. At the peak inspiration point of the inflation curve d. Above the upper inflection point of the deflation curve ANS: D
The level of applied PEEP should be set 3–4 cm H2O above the upper inflection point of the deflation limb of the P–V curve to help maintain an open lung. 13. What is the optimal PEEP level given the following information?
Time
0600
0615
0625
0635
0640
0650
PEEP PaO2 (FIO2 = 0.6) Cs (mL/cm H2O) BP a. b. c. d.
0 50 16 140/90
5 62 21 130/90
8 75 28 120/90
10 81 38 120/90
12 86 34 118/80
15 103 30 100/70
8 cm H2O 10 cm H2O 12 cm H2O 15 cm H2O
ANS: B
At a PEEP of 10 cm H2O, the Cs is at its highest level, and the PaO2 and BP are at acceptable levels. At 12 cm H2O, the Cs is reduced, and it declines further at a PEEP of 15 cm H2O. 14. What is the optimal PEEP level given the following information?
Time PEEP P(a-et)CO2 Compliance BP a. b. c. d.
0700 0 11 26 138/90
0710 5 10 28 128/93
0720 8 6 34 120/86
0735 10 13 30 100/70
0740 12 15 27 100/70
0755 15 15 25 105/75
8 cm H2O 10 cm H2O 12 cm H2O 15 cm H2O
ANS: A
At a PEEP of 8 cm H2O, the P(a-et)CO2 has been minimized, meaning that a maximum number of alveoli have been recruited without overdistention. At a PEEP of 10 cm H2O, the P(a-et)CO2 increases. This means that too much PEEP has been added. At the same time, the compliance drops from 34 mm Hg at a PEEP of 8 cm H2O to 30 mm Hg at a PEEP of 10 cm H2O. This correlates with a decrease in cardiac output and the drop in blood pressure. 15. Which of the following is the most appropriate PEEP level for the patient whose information
is in the table below? Time 0140 PEEP (cm H2O) 5 CO (L/min) 3.5 Mixed venous PO2 28 (mm Hg) BP 140/90 a. b. c. d.
10 cm H2O 12 cm H2O 15 cm H2O 18 cm H2O
ANS: B
1050 8 3.5 39
0155 10 3.6 43
0200 12 3.6 45
0205 15 3.2 42
0210 18 3.2 27
133/90
124/90
120/80
115/78
100/70
At a PEEP of 12 cm H2O, the cardiac output is at its highest level (3.6 L/min), and the mixed venous PO2 is at its highest level. This correlates with an enhancement in cardiac performance. However, at a PEEP of 15 cm H2O, both these indices, as well as the blood pressure, are reduced, meaning that the alveoli are overdistended and the point of optimal PEEP is no longer present. 16. The level of PEEP that is most appropriate for a patient with the information shown below is
which of the following? Time PEEP (cm H2O) Cs (mL/cm H2O) P(a-et)CO2 (mm Hg) PaO2/FIO2 a. b. c. d.
0725 5 27 8.8 159
0730 8 28 6.2 190
0742 10 34 4.8 237
0748 12 29 4.9 237
0755 15 29 6.5 221
0800 18 25 10 204
8 cm H2O 10 cm H2O 12 cm H2O 15 cm H2O
ANS: B
At a PEEP of 10 cm H2O, the static compliance is at its highest level (34 mL/cm H2O), and the arterial to end tidal CO2 tension gradient is at its lowest (4.8 mm Hg). This means that at a PEEP of 10 cm H2O, this patient’s FRC has been restored and the effectiveness of ventilation has been optimized. With PEEP higher than 10 cm H2O, these values show that the alveoli are being overstretched. The PaO2/FIO2 is also at its highest level of 237. 17. A patient is being ventilated with a PEEP of 10 cm H2O and an FIO2 of 0.4. The arterial blood
gas results show that the patient remains hypoxemic, and the respiratory therapist increases the PEEP to 18 cm H2O, maintaining the FIO2 at 0.4. The patient’s static compliance changes from 28 to 22 mL/cm H2O just after this change. The respiratory therapist should do which of the following? a. Decrease PEEP to 10 cm H2O and increase the FIO2 to 0.6. b. Decrease PEEP to 15 cm H2O and measure static compliance. c. Keep PEEP at 18 cm H2O and increase the FIO2 to 0.6. d. Increase PEEP to 20 cm H2O and measure static compliance. ANS: B
The increase in PEEP from 10 to 18 cm H2O caused overdistention of the gas exchange units. This is evidenced by the decrease in compliance from 28 to 22 mL/cm H2O. PEEP should be increased in increments of 3–5 cm H2O at a time. Therefore, the respiratory therapist should step the PEEP back to 13–15 cm H2O and check the static compliance. 18. A patient with ARDS has the slow pressure–volume loop shown below. Based on this loop, at
what level should PEEP be set?
a. b. c. d.
10 cm H2O 12 cm H2O 18 cm H2O 22 cm H2O
ANS: D
The rapid change in the slope of the deflation curve identifies the upper inflection point on the deflation portion of the curve as approximately 20 cm H2O. PEEP should be set 2–3 cm H2O above the upper inflection point, which is 22 cm H2O.
19. What is the Pflex on the following pressure–volume loop?
a. b. c. d.
10 cm H2O 15 cm H2O 19 cm H2O 23 cm H2O
ANS: C
The Pflex, or lower inflection point on the inspiratory limb, is the point on the curve where the slope of the inspiratory line changes significantly (see the following figure).
20. Regardless of the procedure used to establish an appropriate PEEP level, ventilating pressures
should not be allowed to exceed which of the following? Upper inflation point on the inspiratory limb (UIPi) 2–3 cm H2O above the UIPi 30 cm H2O Lower inflection point on the inspiratory limb
a. b. c. d.
ANS: A
Regardless of the procedure used to establish an appropriate PEEP level, ventilating pressures should not be allowed to exceed the UIP on the UIPi, because injury to lungs can occur if the lungs become overstretched. The appearance of the UIP on the graphic display may be influenced by the type of recruitment procedure used. For example, in one study, when the VT was set low (5–6 mL/kg), the UIP was 26 cm H2O. 21. Despite the risk, it is still important to use PEEP, because it can prevent alveolar collapse
during exhalation and reopening, even when a low VT is used. It now is theorized that it is important to use the pressure–volume loop to set-PEEP . a. at the upper inflection point detected during inflation of the lung b. above the upper inflection point detected during deflation of the lung c. at the lower inflection point detected during inflation of the lung d. at the peak inspiration point detected during inflation of the lung ANS: B
Regardless of the procedure used to establish an appropriate PEEP level, ventilating pressures should not be allowed to exceed the UIP on the UIPi, because injury to lungs can occur if the lungs become overstretched. The appearance of the UIP on the graphic display may be influenced by the type of recruitment procedure used. 22. During a patient case study, increasing increments of PEEP showed no significant effects until
15 cm H2O was used, at which time the PaO2 improved markedly. This represents the point at which . a. cardiac output decreased b. airway resistance decreased c. hemoglobin saturation improved d. alveolar recruitment probably occurred
ANS: D
Recruitment maneuvers can produce varying results among patients. In patients who respond to an RM, PaO2 increases, PaCO2 decreases, and the change in pressure (P) required to cause an acceptable VT decreases. 23. In which ventilator mode should a patient receiving a sustained inflation technique be placed? a. VC-CMV b. APRV c. PC-IMV d. CPAP/spontaneous ANS: D
To perform the sustained inflation technique, the ventilator needs to be set in the CPAP/spontaneous mode, because no mechanical breaths should be given during the procedure. The patient also requires sedation and short-term paralysis during this procedure. 24. To perform a slow-flow (quasi-static) technique for determining the appropriate PEEP level,
the most appropriate ventilator flow setting is which of the following? 2 L/min 6 L/min 10 L/min 14 L/min
a. b. c. d.
ANS: A
Although flow rates up to 9 L/min can be used, the higher flow rates cause a slight shift to the right of the resulting P–V curve. The single-breath slow flow should be 2 L/min. 25. The highest pressure attained during the slow-flow (quasi-static) technique should be
cm H2O. a. 25 b. 35 c. 45 d. 55 ANS: C
The slow flow for static P-V measurement uses a single breath delivered at 2 L/min until the pressure reaches 45 cm H2O. 26. The point on a static pressure–volume curve (SPV) where the alveoli begin to open is referred
to as which of the following? a. Lower inflection point on the inflation limb b. Upper inflection point on the inflation limb c. Upper inflection point on the deflation limb d. Lower inflection point on the deflation limb ANS: A
At the lower inflection point on the inflation limb, the slope of the line changes significantly. It originally was believed that this point represents the opening of most of the collapsed alveoli. However, it is the point at which the alveoli begin to open. Even at the upper inflection point on the inflation limb, the alveoli are still being recruited in some parts of the lungs.
27. The “sigmoid” shape of the static pressure–volume lung recruitment maneuver indicates
which of the following? All parts of the lungs open with the same pressure. Independent portions of the lungs open with the same pressure. Dependent portions of the lungs open with different pressures. Lung units open at different times with different pressures.
a. b. c. d.
ANS: D
The shape of the pressure–volume curve suggests that different areas of the lung open at different pressures during the recruitment maneuver. As pressure is exerted every few seconds, different areas of the lungs are recruited. This occurs between the lower inflection point on the inspiratory limb up to the upper inflection point on the inspiratory limb. 28. “Loose atelectasis,” or compression atelectasis, is most often associated with a. ALI b. ARDS c. anesthesia d. pulmonary fibrosis
.
ANS: C
Compression atelectasis, the result of gravitational pressure from lung and heart tissue, often occurs with anesthesia. 29. A recruitment maneuver (RM) is being performed on a patient receiving mechanical
ventilation with PCV. During the maneuver the mode remains in PCV, rate = 10/min, I:E = 1:2, and PIP = 35 cm H2O. The following information is documented during the RM: Time 0800 0805 0810 0815 0820 0825 0830 0835 0840 PEEP 10 15 20 25 30 25 20 15 10 24 29 34 25 22 27 31 36 32 Static compliance BP 126/68 124/66 118/58 110/55 106/58 112/60 118/62 115/60 117/62 HR 108 108 105 100 100 102 105 106 105 After the RM, the lungs are reinflated. At what level should the PEEP be set for this patient? a. 12 cm H2O b. 17 cm H2O c. 22 cm H2O d. 27 cm H2O ANS: A
This is the PCV with increased PEEP recruitment technique. The point of decreased compliance on deflation represents the UIPd of the lungs. Once the lungs have been reinflated to allow reopening of lung units, PEEP is decreased until a pressure 2 cm H2O above the UIPd is obtained. For this patient, that would be 12 cm H2O. 30. The patient with which of the following assessment findings meets the criteria for beginning
weaning from PEEP? PaO2 = 85 mm Hg; FIO2 = 0.6; Cs = 20 mL/cm H2O; PEEP = 12 cm H2O PaO2 = 100 mm Hg; FIO2 = 0.9; Cs = 22 mL/cm H2O; PEEP = 10 cm H2O PaO2 = 150 mm Hg; FIO2 = 0.7; Cs = 25 mL/cm H2O; PEEP = 12 cm H2O PaO2 = 95 mm Hg; FIO2 = 0.3; Cs = 30 mL/cm H2O; PEEP = 15 cm H2O
a. b. c. d.
ANS: D
The criteria for initiation of weaning from PEEP include: (1) an acceptable PaO2 (90 mm Hg) on an FIO2 0.4; (2) hemodynamic stability; (3) absence of sepsis; (4) improved CL (e.g., CS > 25 mL/cm H2O); and (5) PaO2/FIO2 ratio >250–300. Choice “A” does not meet the minimum PaO2 or the minimum FIO2 and has a low Cs. Choice “B” has the appropriate PaO2, but the FIO2 is high and the Cs is low. Choice “C” has a high PaO2, but the FIO2 is 0.7, the calculated PaO2/FIO2 ratio is 214, and the compliance is just at the acceptable level. Choice “D” has all acceptable criteria, including a calculated PaO2/FIO2 ratio of 317. 31. An invasively ventilated patient with ARDS is on PC-CMV, PIP = 30 cm H2O, PEEP = 12 cm
H2O, FIO2 = 1.0. The patient’s returned VT is 320 mL. The ABG results on these settings are: pH 7.3, PaCO2 53 mm Hg, PaO2 62 mm Hg. The patient is placed in the prone position, and after 1 hour, ABG results show: pH 7.38, PaCO2 46 mm Hg, PaO2 83 mm Hg. The respiratory therapist should do which of the following? a. Keep the patient in the prone position. b. Place the patient in the supine position. c. Keep the patient in the prone position and decrease the FIO2. d. Place the patient in the supine position and decrease PEEP. ANS: C
This patient has shown a positive response to the prone position; therefore, the patient can be maintained in this position for 2–12 hours. A reduction in the FIO2 would be appropriate, because the level is at 1.0. 32. A patient with extensive infiltrates throughout the right lung should be placed in which of the
following positions to improve oxygenation? Left lung down laterally Right lung down laterally Left lung down with right lung 45 degrees from supine Right lung down with left lung 45 degrees from supine
a. b. c. d.
ANS: A
To improve oxygenation without uneven distribution of PEEP to the normal lung, the patient should be placed with the “good lung” down.
Chapter 14: Ventilator-Associated Pneumonia Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Pneumonia that was not incubating at the time of admission is one that develops a minimum
of how many hours after admission? 12 hours 24 hours 48 hours 72 hours
a. b. c. d.
ANS: C
Pneumonias that develop 48 hours after a patient is admitted or placed on a mechanical ventilator are hospital-acquired pneumonias. 2. The type of organism that most often causes ventilator-acquired pneumonia is which of the
following? Fungi Bacteria Viruses Protozoa
a. b. c. d.
ANS: B
Ventilator-associated pneumonia (VAP) is most often caused by bacterial infections, but it can also be caused by fungal infections or associated with viral epidemics. 3. A patient was intubated in the emergency department just after arrival at the hospital from
home. This patient develops VAP 36 hours after intubation. What type of pneumonia is this considered? a. Early-onset VAP b. Late-onset VAP c. Healthcare-associated pneumonia d. Nonhospital-acquired pneumonia ANS: D
The development of pneumonia within 48 hours of admission and intubation is a result of an infection that was incubating at the time of admission. 4. The mortality rate for VAP associated with prolonged hospital stays is which of the following? a. 5–25% b. 15–40% c. 25–50% d. 45–75% ANS: C
The mortality rate for ventilator-associated pneumonia is 25–50%. 5. Sixty percent of all VAP infections are caused by which of the following?
a. b. c. d.
Aerobic gram-negative bacilli Anaerobic gram-negative bacilli Aerobic gram-negative rods Anaerobic gram-positive cocci
ANS: A
Aerobic gram-negative bacilli have accounted for nearly 60% of all VAP infections. The most common of these are Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter sp. 6. The most common gram-positive bacterium that causes ventilator-associated pneumonia is
which of the following? Streptococcus pneumoniae Enterococcus faecalis Methicillin-resistant Staphylococcus aureus Pseudomonas aeruginosa
a. b. c. d.
ANS: C
The predominant gram-positive bacterium that causes VAP is methicillin-resistant Staphylococcus aureus (MRSA). Pseudomonas aeruginosa is a gram-negative bacterium. 7. Patients with chronic obstructive pulmonary disease (COPD) are at higher risk for infection
with which of the following organisms? 1. Haemophilus influenzae 2. Pseudomonas aeruginosa 3. Moraxella catarrhalis 4. Staphylococcus aureus a. 1 and 2 only b. 1 and 3 only c. 2 and 4 only d. 3 and 4 only ANS: B
Patients with COPD have an increased risk for infection with H. influenzae, S. pneumoniae, and M. catarrhalis, whereas patients with cystic fibrosis are susceptible to P. aeruginosa and S. aureus infections. 8. The incidence of ventilator-associated pneumonia for all intubated patients is a. 8–28% b. 15–35% c. 25–50% d. 38–76% ANS: A
The incidence of VAP ranges from 8% to 28% for all intubated patients. 9. The mortality rate for VAP depends on which of the following?
1. Length of stay on the ventilator 2. Presence of underlying disease 3. Prior antimicrobial therapy 4. Presence of a heated humidifier
.
a. b. c. d.
1 and 2 only 2 and 3 only 1 and 4 only 2, 3, and 4 only
ANS: B
The overall attributable mortality rate for VAP depends on the infecting organism or organisms, the presence of underlying disease, and prior antimicrobial therapy. 10. Healthy individuals usually have which of the following bacteria in their upper airways? a. Haemophilus sp. b. Acinetobacter sp. c. Pseudomonas aeruginosa d. Staphylococcus aureus ANS: A
The upper airways of healthy individuals typically contain nonpathogenic bacteria, such as the viridans group of streptococci, Haemophilus sp., and anaerobes. 11. Effective treatment of ventilator-associated pneumonia can be ensured by diagnosis based on
findings from which of the following? Chest radiographs Hematological studies Bronchial alveolar lavage Patient signs and symptoms
a. b. c. d.
ANS: C
The American Thoracic Society and the Infectious Diseases Society of America suggest that quantitative cultures of the lower respiratory secretions be obtained by bronchial alveolar lavage or protected specimen brush to ensure effective treatment of patients with VAP. Chest radiographs, hematological studies, and patient signs and symptoms should be used to start empiric antibiotic therapy before the quantitative cultures are performed. 12. Calculate the Clinical Pulmonary Infection Score (CPIS) for a patient with the following
assessments: 56-year-old female, post motor vehicle accident, intubated, and mechanically ventilated for 4 days. Static compliance is 42 cm H2O/L. Tracheobronchial suctioning reveals a moderate amount of yellow secretions; culture and sensitivity are pending. Breath sounds reveal bilateral lower lobe coarse rhonchi. Chest radiograph shows diffuse infiltrates. Partial pressure of oxygen in the arteries (PaO2) is 72 mm Hg on 40% supplemental oxygen. Patient has a temperature of 39.2 C, and white blood cell count (WBC) is 12,800 µL. a. CPIS = 5 b. CPIS = 6 c. CPIS = 7 d. CPIS = 8 ANS: C
Using the CPIS criteria found in Table 14-2, the score is calculated as follows: Temperature of 39.2 C = 2 points; white blood cell (WBC) is 12,800 µL = 1 point; secretions are present and nonpurulent = 1 point; partial pressure of oxygen in the arteries/fractional inspired oxygen (PaO2/FIO2) = 72/0.4 = 180 with no acute respiratory distress syndrome (ARDS) = 2 points; chest radiograph shows diffuse infiltrates = 1 point; and compliance and saturation in the blood phase (C & S) is pending = 0 point, for a total of 7 points. 13. A patient with which of the following CPIS criteria should be placed on empiric antibiotic
therapy pending the outcome of a bronchial alveolar lavage? CPIS = 4 CPIS = 5 CPIS = 6 CPIS = 7
a. b. c. d.
ANS: D
When all six criteria are used, a score >6 is considered evidence of the presence of VAP. It is generally accepted that measurements of the CPIS should be performed at the beginning of antibiotic therapy and after 2–3 days to reevaluate the effectiveness of the treatment. 14. Critically ill patients receiving invasive mechanical ventilation have been found to have which
of the following microorganisms not typically present in healthy individuals? Anaerobes Haemophilus species Gram-negative bacilli Viridans group of streptococci
a. b. c. d.
ANS: C
During critical illnesses, particularly in patients with an endotracheal tube and those receiving mechanical ventilation, a dramatic shift occurs in the flora of the oropharyngeal tract to gramnegative bacilli and Staphylococcus aureus. 15. Reasons for the shift in oropharyngeal flora in patients receiving invasive mechanical
ventilation with endotracheal tubes include which of the following? Lowered pH levels Increase in mucus-producing cells Decreased production of proteases Decreased mucosal immunoglobulin A
a. b. c. d.
ANS: D
The shift in flora is most likely due to a number of factors that compromise host defense mechanisms. These include comorbidities, malnutrition, reduced levels of mucosal immunoglobulin A, increased production of proteases, exposed and denuded mucous membranes, elevated airway pH, and an increased number of airway receptors for bacteria as a result of acute illness and previous antimicrobial use. 16. Relying on clinical findings for the treatment of ventilator-associated pneumonia may do
which of the following? Decrease the morbidity of VAP. Decrease the mortality of VAP. Create multidrug-resistant organisms. Reduce the need for invasive microbiological procedures.
a. b. c. d.
ANS: C
Relying on clinical findings alone can result in unnecessary use of broad-range antibiotics, which in turn can lead to the emergence of multidrug-resistant strains of microorganisms. 17. The initial empiric antibiotic used to treat suspected methicillin-resistant Staphylococcus
aureus in a patient with late-onset VAP is which of the following? Linezolid Gentamicin Tobramycin Ciprofloxacin
a. b. c. d.
ANS: A
Patients with late-onset VAP who develop MRSA should be treated with linezolid or vancomycin. 18. The initial empiric antibiotic used to treat suspected methicillin-resistant Staphylococcus
aureus in a patient with early-onset VAP is which of the following? Linezolid Vancomycin Gentamicin Levofloxacin
a. b. c. d.
ANS: D
The initial empiric antibiotic therapy for patients with early-onset VAP suspected of being MRSA is different from the empiric antibiotic therapy for late-onset VAP or for patients with risk factors for multidrug-resistant pathogens. Suggested empiric antibiotic therapy for earlyonset VAP with suspected MRSA includes levofloxacin, monifloxacin, or ciprofloxacin. 19. A 63-year-old male, post head trauma, is intubated and has been mechanically ventilated for
78 hours. The respiratory therapist notes the following during ICU rounds: partial pressure of oxygen in the arteries (PaO2) is 82 mm Hg on 60% supplemental oxygen with a positive endexpiratory pressure (PEEP) of 8 cm H2O; static compliance is averaging 38–41 cm H2O/L; breath sounds are diminished bilaterally. Bronchoalveolar lavage (BAL) results are pending, but MRSA is suspected. Chest radiograph shows bilateral, patchy infiltrates. Patient has a temperature of 38.8 C, and the most recent white blood cell (WBC) count is 11,300 µL. The most appropriate recommendation for this patient is which of the following? a. Monotherapy with an antipseudomonal carbapenem b. Monotherapy with an antipseudomonal fluoroquinolone c. Combination therapy with two types of antipseudomonal agents and vancomycin d. Combination therapy with ampicillin/sulbactam and linezolid ANS: C
This patient has late-onset ventilator-associated pneumonia because he has been intubated and has received mechanical ventilation for longer than 72 hours. Because MRSA is suspected, combination antibiotic therapy should be used. According to Table 14-2 this would include two antipseudomonal agents plus either vancomycin or linezolid. Therapy should be adjusted once the microbiological data confirm the organism. 20. Which of the following is a method to reduce the risk for VAP? a. Nasally intubate whenever possible.
b. Provide constant nasogastric tube feedings. c. Keep patient in a semirecumbent position. d. Only use heated wire circuits. ANS: C
Nasal intubation increases the risk for sinusitis, which is associated with ventilator-associated pneumonia. Intermittent nasogastric tube feedings, keeping the patient in a semirecumbent position, and using heat/moisture exchangers (HME) whenever possible are all methods to decrease the occurrence of VAP. 21. Which pathogen is commonly found in patients who had percutaneous tracheostomies? a. Klebsiella spp. b. Pseudomonas sp. c. Enterobacter spp. d. Candida albicans ANS: B
A common pathogen that causes infection after percutaneous tracheotomy is Pseudomonas sp. 22. To avoid ventilator-associated pneumonia, how often should ventilator circuits be changed? a. Every 24 hours b. Every 48 hours c. Once weekly d. When visibly dirty ANS: D
There is no protocol for cleaning ventilator circuits other than when visibly dirty. 23. The main strategy for the management of VAP focuses on which of the following? a. Pharmacological treatment b. Early diagnosis and treatment c. Prophylactic antibiotic therapy d. Reduction of host-related risk factors ANS: B
Although considerable debate has taken place among clinicians regarding the most effective means of diagnosing and treating ventilator-associated pneumonia, it is agreed that successful management of VAP requires early diagnosis and appropriate use of antibiotic therapy to prevent the emergence of multidrug-resistant (MDR) microorganisms. 24. A “ventilator bundle” may include which of the following?
1. Keeping the head of the bed at 30 degrees from the horizontal 2. Changing the ventilator circuits every 48 hours 3. Using heated humidifiers whenever possible 4. Using noninvasive positive pressure ventilation (NPPV) whenever possible a. 1 and 3 only b. 1 and 4 only c. 2 and 3 only d. 1, 2, and 4 only ANS: B
“Ventilator bundles” are evidence-based practices that can significantly reduce the incidence of VAP. Keeping the patient in a semirecumbent position decreases the risk for aspiration. Using NPPV when possible can significantly lower the rate of nosocomial pneumonia. Ventilator circuits should be changed only when they are visibly dirty, and HMEs should be used whenever possible, because most can filter and all can eliminate condensation in the ventilator circuit. 25. According to the Centers for Disease Control (CDC) and National Healthcare Safety Network
(NHSN), the proposed and updated definition for VAP includes which of the following? 1. Objective data 2. Patient’s family history 3. A clearly defined time criteria 4. Chest radiograph images a. 1 and 3 only b. 2 and 3 only c. 2, 3, and 4 only d. 1, 2, and 3 only ANS: A
In 2011, the Centers for Disease Control (CDC) and National Healthcare Safety Network (NHSN) proposed an updated definition that was designed to improve the reporting criteria for VAP used by institutions. Although the CDC surveillance definition incorporates the general features of the ATS/IDSA definition, several points are noteworthy. The CDC surveillance definition relies on the use of only objective data, clearly defined time criteria, and the exclusion of radiographic imaging to diagnose the presence of pneumonia in ventilated patients. 26. The pathogenesis of VAP involves
1. colonization of the aerodigestive tract. 2. aspiration of contaminated secretions into the lower airways. 3. increased use of silver-coated endotracheal tubes. 4. colonization of lower airways and lung parenchyma. a. 2 and 3 only b. 2, 3, and 4 only c. 1, 2, and 3 only d. 1, 2, and 4 only ANS: D
The pathogenesis of VAP most often involves colonization of the aerodigestive tract with pathogenic bacteria, aspiration of contaminated secretions into the lower airways, followed by colonization of the normally sterile lower airways and lung parenchyma with these infectious microorganisms. Recent studies have demonstrated that antimicrobial-coated ET tubes can reduce the incidence of VAP by delaying bacterial colonization and biofilm formation on the tube’s inner lining. Laboratory studies have suggested that silver is an ideal coating because it is nontoxic, antimicrobial, and has anti-adhesive properties.
Chapter 15: Sedatives, Analgesics, and Paralytics Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. A mechanically ventilated patient is being assessed for her level of sedation. The patient is
semiasleep and responds to verbal commands. What score on the Ramsay Sedation Scale should be assigned to this patient? a. 2 b. 3 c. 4 d. 5 ANS: B
A patient who is semiasleep but responds to verbal commands would be given a score of 3 on the Ramsay Sedation Scale. 2. Which of the following is the sedation scale that uses a graduated single category? a. Comfort Scale b. Motor Activity Assessment Scale c. Ramsay Sedation Scale d. Sedation-Agitation Scale ANS: C
The Ramsay Sedation Scale is a graduated, single-category scale that is easy to perform and provides a numerical value that can be used as a target for achieving adequate sedation. 3. What range of scores on the Ramsay Sedation Scale indicates adequate sedation? a. 1–3 b. 2–4 c. 3–5 d. 5–6 ANS: B
A score of 2–4 on the Ramsay scale indicates adequate sedation. 4. The group of drugs that interact with GABA receptor complex on neurons in the brain is
which of the following? Opioids Paralytics Benzodiazepines Depolarizing agents
a. b. c. d.
ANS: C
Benzodiazepines exert their effects through a nonspecific depression of the central nervous system. This is accomplished when these drugs bind to benzodiazepine sites on the gammaaminobutyric acid (GABA) receptor complex on neurons in the brain.
5. A patient with hypovolemic shock secondary to widespread second- and third-degree burns is
being mechanically ventilated. The patient appears agitated, and the respiratory therapist is unable to synchronize the ventilator to the patient. Which drug can the respiratory therapist suggest to the ICU team to sedate this patient and synchronize ventilation? a. Fentanyl b. Morphine c. Propofol d. Succinylcholine ANS: A
Fentanyl has minimal effects on the cardiovascular system and does not cause histamine release, as does morphine. It also has minimal effects on the renal system compared with other opioids. Therefore, fentanyl is the opioid of choice for patients with unstable hemodynamic status and renal insufficiency. Morphine and propofol have hemodynamic effects that may worsen this patient’s hypovolemia. Succinylcholine is a paralyzing agent. Paralyzing agents should not be given without sedatives. 6. What drug reverses the sedative effects of benzodiazepines? a. Naloxone b. Flumazenil c. Fentanyl d. Vecuronium ANS: B
Flumazenil prevents the sedative effects of benzodiazepines by competitively binding to benzodiazepine receptors. Naloxone is an opioid antagonist used to facilitate opioid withdrawal. Fentanyl is a synthetic opioid that is more potent than morphine. Vecuronium is a nondepolarizing paralyzing agent. 7. The drug of choice for sedating mechanically ventilated patients in the ICU for longer than 24
hours is which of the following? Lorazepam (Ativan) Midazolam (Versed) Diazepam (Valium) Propofol (Diprivan)
a. b. c. d.
ANS: A
Lorazepam (Ativan) is the drug of choice for sedating mechanically ventilated patients in the ICU for longer than 24 hours. 8. A patient who is receiving mechanical ventilation in the ICU is found to be wildly agitated.
The most appropriate drug to control this delirium is which of the following? Propofol Fentanyl Haloperidol Lorazepam
a. b. c. d.
ANS: C
Neuroleptics, such as haloperidol, are routinely used to treat patients demonstrating extreme agitation and delirium. Propofol is a general anesthetic used for sedation. Fentanyl is a synthetic opioid that is approximately 100–150 times more potent than morphine. Lorazepam (Ativan) is the drug of choice for sedating mechanically ventilated patients in the ICU for longer than 24 hours. 9. A patient with head trauma and an elevated ICP is being ventilated postoperatively and shows
signs of asynchrony with the mechanical ventilator. The most appropriate medication to sedate this patient is which of the following? a. Morphine b. Propofol c. Propofol and morphine d. Fentanyl ANS: C
Propofol and morphine, administered simultaneously, allow for greater control of the ICP than morphine alone. Propofol reduces cerebral blood flow and intracranial pressure, making it a useful sedative for neurosurgical patients. In fact, propofol has been shown to be more effective than fentanyl in reducing ICP in patients with traumatic brain injury. 10. Caution should be used when administering propofol for longer than 48 hours in pediatric
patients because of what adverse effect? a. Lethargy b. Lactic acidosis c. Cardiac dysrhythmias d. Reduced cerebral blood flow ANS: B
Prolonged use of propofol (longer than 48 hours) in pediatric patients has been associated with the development of lactic acidosis. 11. Which of the following drugs has the potential for causing bronchospasm in patients with
asthma and hypersensitive airways? a. Fentanyl b. Propofol c. Diazepam d. Morphine ANS: D
Morphine increases serum histamine levels and is associated with bronchospasm in patients with asthma and those with hypersensitive airways. 12. Neuromuscular blocking agents are commonly used in mechanically ventilated patients when
which of the following occurs? a. The patient is in severe pain. b. Cardiac arrhythmias are present. c. The patient develops anxiety as a result of ICU psychosis. d. Patient-ventilator asynchrony cannot be corrected. ANS: D
Paralytics or neuromuscular blocking agents are used for patient-ventilator asynchrony that cannot be corrected by adjusting ventilator settings. 13. The neuromuscular blocking agent that resembles acetylcholine in chemical structure is which
of the following? Succinylcholine Pancuronium Vecuronium Cisatracurium
a. b. c. d.
ANS: A
Succinylcholine resembles acetylcholine in chemical structure. 14. Permissive hypercapnia is needed to protect patients with ARDS from atelectrauma. Which of
the following medications is appropriate to facilitate this? a. Propofol b. Fentanyl c. Midazolam d. Cisatracurium ANS: D
Neuromuscular blocking agents are used to facilitate less conventional mechanical ventilation strategies. Cisatracurium is a nondepolarizing paralytic agent. Propofol is an anesthetic. Fentanyl is an opioid, and midazolam is a benzodiazepine. 15. The train-of-four response is used to assess a patient’s level of paralysis during high-
frequency oscillatory ventilation, and the patient’s foot twitches four times. The most appropriate evaluation of this circumstance is which of the following? a. Nothing need be done; paralysis is adequate. b. The paralyzing agent is moderately effective. c. The paralyzing agent needs to be readministered. d. Propofol needs to be added to enhance the effect. ANS: C
For the train-of-four assessment, an electrical current consisting of four impulses is applied to the peripheral nerve over 2 s; the muscle contractions (twitches) produced provide information about the level of paralysis. With four twitches, the paralyzing agent needs to be readministered if continued paralysis is required. 16. The paralytic agent associated with precipitation of malignant hyperthermia is which of the
following? Vecuronium Cisatracurium Pancuronium Succinylcholine
a. b. c. d.
ANS: D
Succinylcholine can precipitate malignant hyperthermia in susceptible individuals. Malignant hyperthermia is a rare but potentially fatal disorder characterized by sustained skeletal muscle depolarization. It occurs in 1 in 50,000 adults and 1 in 15,000 pediatric patients.
17. Which of the following describes moderate sedation? a. The patient can respond to verbal commands, although cognitive function may be
impaired. b. The patient is not easily aroused but can respond to painful stimulation. c. The patient can perform purposeful response following repeated or painful stimulation. d. The patient cannot be aroused, even by painful stimulation. ANS: C
Minimal Sedation Patients can respond to verbal commands, although cognitive function may be impaired. Ventilatory and cardiovascular functions are unaffected. Moderate Sedation (Conscious Sedation) The patient can perform purposeful response following repeated or painful stimulation. Spontaneous ventilation is adequate, and cardiovascular function is usually maintained. Deep Sedation The patient is not easily aroused but can respond to painful stimulation. Spontaneous ventilation and maintenance of patient airway may be inadequate. Cardiovascular function is usually maintained. Anesthesia This level involves general anesthesia, spinal, or major regional anesthesia; local anesthesia is not included. Patient cannot be aroused, even by painful stimulation. Ventilatory assistance is typically required (i.e., artificial airway and positive pressure ventilation). Cardiovascular function may be impaired. 18. What drug reverses the effects of opiates? a. Naloxone b. Flumazenil c. Fentanyl d. Vecuronium ANS: A
Naloxone is an opioid antagonist used to facilitate opioid withdrawal. Flumazenil prevents the sedative effects of benzodiazepines by competitively binding to benzodiazepine receptors. Fentanyl is a synthetic opioid that is more potent than morphine. Vecuronium is a nondepolarizing paralyzing agent.
Chapter 16: Extrapulmonary Effects of Mechanical Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The mode that causes the greatest reduction in cardiac output during ventilation is which of
the following? CPAP IMV IMV with PEEP VC-CMV with PEEP
a. b. c. d.
ANS: D
VC-CMV with PEEP causes the highest mean airway pressure; this results in the greatest reduction in venous return and thus cardiac output. 2. High tidal volumes and/or high levels of PEEP can cause which of the following? a. Improvement in pulmonary blood flow b. Increased right ventricular afterload c. Interventricular septum shifts to the right d. Increased myocardial perfusion ANS: B
High tidal volumes and/or high levels of PEEP result in increased resistance to blood flow through the pulmonary circulation; this increases right ventricular afterload. In addition, the right ventricle becomes overdistended, causing a decrease in RV output. Dilation of the RV can also force the interventricular septum to move to the left. Left ventricular output may also be decreased because of the expanding lungs. This plus the decreased venous return lowers cardiac output and decreases the amount of blood perfusing the myocardium. 3. Normovolemic patients experience decreases in cardiac output above what level of PEEP? a. 5 cm H2O b. 8 cm H2O c. 12 cm H2O d. 15 cm H2O ANS: D
Decreases in cardiac output can occur in normovolemic patients with levels of PEEP >15 cm H2O. 4. Which of the following patient conditions is least likely to experience hemodynamic changes
with high alveolar pressures during mechanical ventilation? ARDS Emphysema Kyphoscoliosis Third-degree chest wall burns
a. b. c. d.
ANS: A
Patients with stiff lungs (as in ARDS or pulmonary fibrosis) are less likely to experience hemodynamic changes with high pressures, because less of the alveolar pressure is transmitted to the intrapleural space. Patients with compliant lungs (as in emphysema) or with stiff, noncompliant chest walls (as in kyphoscoliosis and extensive chest wall burns) are more likely to have higher intrapleural pressures with PPV and experience more pronounced cardiovascular effects. 5. The harmful cardiovascular effects of PPV are influenced most by which of the following
pressures? Peak inspiratory pressure Mean airway pressure Positive end-expiratory pressure Transpulmonary pressure
a. b. c. d.
ANS: B
The amount and duration of the pressure applied to the airway, the mean airway pressure, ultimately influences the extent of the harmful cardiovascular effects. The lower the mean airway pressure, the less marked the cardiovascular effects. This pressure takes into account the peak inspiratory pressure, the positive end-expiratory pressure, the inspiratory time, and the total cycle time. 6. Which of the following ventilator parameters would result in the highest mean airway
pressure? PIP = 30 cm H2O; PEEP = 10 cm H2O; TI = 0.5 s; TCT = 5 s PIP = 50 cm H2O; PEEP = 10 cm H2O; TI = 0.5 s; TCT = 5 s PIP = 30 cm H2O; PEEP = 15 cm H2O; TI = 0.5 s; TCT = 5 s PIP = 50 cm H2O; PEEP = 10 cm H2O; TI = 0.5 s; TCT = 5 s
a. b. c. d.
ANS: C
7. Which of the following can increase the physiological dead space in apneic patients receiving
volume control ventilation? I:E ratio >1:1 A slow flow rate Adding an inflation hold Inspiratory time <0.5 s
a. b. c. d.
ANS: D
In an apneic patient receiving volume control ventilation, an inspiratory time that is too short (i.e., <0.5 s) may result in an increase in physiological dead space. Large I:E ratios and addition of an inflation hold increase the mean airway pressure. A slow flow rate can inverse the I:E ratio and also cause an increase in mean airway pressure. 8. During spontaneous breathing, the fall in intrapleural pressure that draws air into the lungs
during inspiration also draws blood into the major thoracic vessels. This phenomenon increases which of the following? a. Systemic vascular resistance b. Right ventricular afterload c. Right ventricular preload d. Pulmonary capillary resistance
ANS: C
During spontaneous breathing, the fall in intrapleural pressure that draws air into the lungs during inspiration also draws blood into the major thoracic vessels and heart. With this increased return of blood to the right side of the heart and the stretching and enlargement of the right-side heart volume, the right ventricular preload increases, resulting in an increased right ventricular stroke volume (i.e., Frank-Starling mechanism). 9. Calculate the cerebral perfusion pressure when the mean arterial blood pressure is 120 mm Hg
and the ICP is 14 mm Hg. a. 134 mm Hg b. 106 mm Hg c. 120/14 mm Hg d. 134/106 mm Hg ANS: B
MABP ICP = CPP 10. Urinary output is severely reduced when the renal arterial pressure decreases below what
level? 75 mm Hg 85 mm Hg 95 mm Hg 105 mm Hg
a. b. c. d.
ANS: A
Although urinary output stays fairly constant over a wide range of arterial pressures, it is severely reduced if the renal arterial pressure drops below 75 mm Hg. 11. Positive pressure ventilation has which of the following effects on the kidneys? a. Increases blood flow to the kidneys b. Redistributes blood flow in the kidneys c. Decreases sodium reabsorption in the kidneys d. Increases urinary output ANS: B
PPV redistributes blood inside the kidneys, which may be an important factor in the changes that occur in kidney function. 12. Mechanical ventilation has an effect on the hormone
, which causes a
decrease in urinary output. a. cortisol b. arginine vasopressin c. parathyroid hormone d. thyroid-stimulating hormone ANS: B
Several different types of hormones may influence urine output during mechanical ventilation. Specifically, these include ADH, atrial natriuretic factor, and the renin-angiotensinaldosterone cascade. Increases in the release of ADH, also called arginine vasopressin, from the posterior pituitary can reduce urine production by inhibiting free water excretion.
13. Positive pressure ventilation increases splanchnic resistance, decreases splanchnic venous
outflow, and may contribute to gastric mucosal ischemia, which can contribute to which of the following? a. Liver metastases b. Gastric mucosal ischemia c. Gastric ulcers d. Increased portal blood flow ANS: C
PPV increases splanchnic resistance, decreases splanchnic venous outflow, and may contribute to gastric mucosal ischemia, which can increase the risk for gastrointestinal bleeding and gastric ulcers. Both of these conditions are complications frequently seen in critically ill patients. 14. Which of the following condition must exist to cause the interventricular septum to move to
the left during positive pressure ventilation? Volume overload Cardiac tamponade Mean airway pressure >15 cm H2O Decreased coronary artery perfusion
a. b. c. d.
ANS: C
Dilation of the RV can force the interventricular septum to move to the left. This phenomenon usually occurs when a high pressure (>15 cm H2O) is used and the patient is volume depleted. 15. Which of the following is the most likely cause of uneven ventilation? a. Low set tidal volumes b. High inspiratory flow rates c. High mean airway pressures d. Elevated peak inspiratory pressures ANS: B
Uneven ventilation is likely to occur with high inspiratory flow. If, for example, the right bronchus is partially obstructed, most of the gas flow would go to the left lung because gas flow follows the path of least resistance. Consequently, a larger volume enters the left lung, creating higher airway pressures in the left lung compared with the right. 16. An otherwise healthy 19-year-old male is currently intubated and being mechanically
ventilated after a motorcycle accident in which he sustained a closed head injury and multiple rib fractures. Before the patient is taken to the operating room for cranial surgery, the respiratory therapist notices that he has jugular vein distention. The most likely cause of this problem is which of the following? a. Increased cardiac output b. Decreased ventricular preload c. Increased intracranial pressure d. Decreased systemic vascular resistance ANS: C
Reduced venous return from the head increases the ICP; this can be caused by positive pressure ventilation and/or, in this case, the head trauma. Increased ICP can be observed clinically by an increase in jugular vein distention.
17. Malnutrition during mechanical ventilation can cause which of the following? a. Increased oxygen consumption b. Increased carbon dioxide production c. Increased work of breathing d. Increased spontaneous ventilation ANS: D
Malnutrition alters a patient’s ability to respond effectively to infection. It also impairs wound healing and severely reduces the ability to maintain spontaneous ventilation because the respiratory muscles are weakened. 18. Which of the following are potential effects of PEEP on heart function?
1. Decreased airway pressure 2. Decreased functional residual capacity 3. Increased airway pressure 4. Increased functional residual capacity a. 1 and 2 only b. 3 and 4 only c. 2 and 4 only d. 1 and 3 only ANS: B
Potential Effects of PEEP in Left Ventricular Dysfunction • Increased airway pressure and intrathoracic pressure lead to decreased venous return that can reduce preload to a failing heart and improve function. • Increased functional residual capacity (FRC) that occurs with the application of PEEP leads to increased pulmonary vascular resistance and increased afterload to the right heart, which may shift the intraventricular septum to the left. This does not seem to alter RV contractility until values for PAP are critical. • Left shift of the intraventricular septum reduces LV volume and decreases the load it must pump. On the other hand, it may also affect LV compliance and either increase or decrease LV function (the response varies). • The mechanical compression of the heart and aorta by the positive pleural pressure can also alter ventricular function. Vascular pressure in the heart and thoracic aorta are transiently increased relative to the extrathoracic aorta (i.e., LV afterload decreases). This response is not always consistent, and cardiac tamponade from PEEP can negatively alter myocardial compliance as well. • Improper ventilator settings may lead to increased work of breathing and oxygen demand, which can affect myocardial oxygen supply and result in myocardial ischemia and reduced LV compliance.
Chapter 17: Effects of Positive Pressure Ventilation on the Pulmonary System Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Biotrauma is caused directly by which of the following? a. High oxygen levels b. Overdistention of alveoli c. Long expiratory times d. Fast respiratory rates ANS: B
High distending volumes result in overdistention of the alveoli, leading to the release of inflammatory mediators from the lungs, which can result in multiorgan failure. The release of these inflammatory mediators is called biotrauma. 2. Alveolar tissue and pulmonary capillary injury is caused by which of the following? a. Barotrauma b. Biotrauma c. Shear stress d. Overdistention ANS: C
Repeated opening and closing of lung units, also called recruitment–derecruitment, generates shear stress, which results in direct tissue injury at the alveolar and pulmonary capillary level. Barotrauma is lung injury caused by high pressure. Biotrauma refers to the release of inflammatory chemical mediators that cause multiorgan failure. Overdistention is the cause of biotrauma. 3. Shear stress injury and loss of surfactant from the resulting unstable lung units result in a loss
of surfactant. This type of pulmonary trauma is known as atelectrauma barotrauma biotrauma volutrauma
.
a. b. c. d.
ANS: A
Shear stress injury and loss of surfactant constitute atelectrauma. Lung injury caused by high levels of pressure and volume is referred to as barotrauma or volutrauma. The release of inflammatory mediators from the lungs that can lead to multiorgan failure is called biotrauma. 4. Ventilator-induced lung injury (VILI) is associated with which of the following? a. Air trapping b. Biotrauma c. Patient-ventilator asynchrony d. Ventilator-associated pneumonia ANS: B
VILI is a lung injury that occurs at the level of the acinus. It is the microscopic level of injury that includes biotrauma, shear stress, and surfactant depletion (atelectrauma). The term ventilator-associated lung injury (VALI) is generally used to refer to lung injury identified as being a consequence of mechanical ventilation. The most common forms of VALI are ventilator-associated pneumonia (VAP), air trapping, patient-ventilator asynchrony, and extraalveolar gas (barotrauma), such as pneumothorax and pneumomediastinum. 5. The RT performs a patient-ventilator system check on a 24-year-old, 5-foot, 10-inch male
patient who has been intubated because of a drug overdose. The RT notices what appears to be swelling around the patient’s upper anterior chest and neck area. Palpation elicits a tissue paper feeling. The ventilator settings are: VC-CMV, rate 12/min with no patient assist, VT 900 mL, PEEP 5 cm H2O, FIO2 0.4, TI 1.2 s. The most appropriate action for the RT to take is which of the following? a. Increase the set flow rate. b. Decrease the set tidal volume. c. Reduce the set respiratory rate. d. Perform emergency needle decompression. ANS: B
Assessment of this patient reveals that he has subcutaneous emphysema, as evidenced by the swelling around the upper anterior chest and neck area and the tissue paper feeling on palpation. This is a form of barotrauma caused by alveolar rupture as a result of too much volume. The PEEP setting is only 5 cm H2O, which is physiological. The VT setting, however, is too high. The IBW for this patient is 75 kg; 900 ÷ 75 = a set volume of 12 mL/kg. This needs to be adjusted to 8–10 mL/kg. The subcutaneous emphysema should subside on its own. 6. The RT responds to the high pressure, high respiratory rate, low exhaled volume, and low
exhaled minute volume alarms of a mechanically ventilated patient in the ICU. Upon entering the room, the RT notices that the patient, who is still attached to the ventilator, appears diaphoretic, tachypneic, tachycardic, and hypertensive. Breath sounds are absent on the left and distant on the right. The patient’s trachea is deviated to the left, and jugular vein distention is present. The endotracheal tube is 24 cm at the teeth. Immediate action should include which of the following? a. Order a chest radiograph in the upright position. b. Administer intravenous etomidate and succinylcholine. c. Pull back the endotracheal tube to 22 cm at the teeth. d. Insert a 14-gauge needle into the second intercostal space right midclavicular line. ANS: D
The ringing of the high pressure alarm for a time has led to the sounding of the low volume and low minute volume alarms. The patient is in apparent respiratory distress, as evidenced by the tachypnea, tachycardia, and diaphoresis. The position of the ET tube at the 24-cm mark is evidence that the tube has slipped into the right main-stem bronchus. However, the absence of breath sounds on the left plus the tracheal deviation to the left, along with the jugular vein distention, is evidence of a tension pneumothorax on the right side. The ET tube appears to have slipped into the right main-stem bronchus and subsequently caused a pneumothorax. This is a life-threatening situation, and the pneumothorax must be decompressed immediately with a 14-gauge needle inserted into the second or third intercostal space on the right midclavicular line.
7. Lung injury is more likely to occur with which of the following with normal lung tissue? a. PA = 25 cm H2O; Ppl = 18 cm H2O b. PA = 29 cm H2O; Ppl = 10 cm H2O c. PA = 30 cm H2O; Ppl = 21 cm H2O d. PA = 45 cm H2O; Ppl = 34 cm H2O ANS: B
Situations in which the lung-distending pressure (i.e., transpulmonary pressure, or PA Ppl) is abnormally high can cause lung injury. PA can be high by itself without causing lung damage, but if PA Ppl is high, lung damage is more likely. The highest transpulmonary pressure is 19 cm H2O, when the PA = 29 cm H2O and the Ppl = 10 cm H2O. 8. What is the minimum transpulmonary pressure that has been associated with lung injury in
animals? 30 cm H2O 40 cm H2O 50 cm H2O 60 cm H2O
a. b. c. d.
ANS: A
Studies show that pressures as low as 30–35 cm H2O cause lung injury in animals. 9. Shear stress is most likely to affect a patient with which of the following? a. PA = 35 cm H2O; Ppl = 21 cm H2O b. PA = 35 cm H2O; Ppl = 12 cm H2O c. PA = 45 cm H2O; Ppl = 33 cm H2O d. PA = 50 cm H2O; Ppl = 38 cm H2O ANS: B
The amount of shear stress across the entire lung can be estimated using the transpulmonary pressure (Pplateau Ppl), where Pplateau represents PA and Ppl is the intrapleural pressure. 10. Healthy areas of lung tissue in a patient with ARDS may be protected from lung injury caused
by overdistention by which of the following? Increasing FIO2 Decreasing PEEP Using the prone position Using a VT of 10–12 mL/kg
a. b. c. d.
ANS: C
Placing a patient with ARDS in a prone position restricts chest wall movement, thereby preventing severe transpulmonary pressure from causing alveolar stretch and edema, or shear stress. Increasing the FIO2 may cause more atelectasis, which could worsen the situation. Decreasing PEEP would derecruit alveoli, shifting the volume to more compliant areas, which could increase the amount of lung injury. Using tidal volumes of 10–12 mL/kg would increase the risk for lung injury. 11. Overdistention of the lungs causes the release of which inflammatory mediators? a. Cytokines b. Alpha-1 antitrypsin c. Histamine
d. Macrophages ANS: A
Overdistention of the lungs causes the release of inflammatory mediators such as cytokines, tumor necrosis factor, platelet-activating factor, thromboxane-B2, tumor necrosis factor alpha, and interleukin-1B. Macrophages are the actual source of some of these mediators. 12. Inappropriate ventilator settings can cause the release of inflammatory mediators within a. b. c. d.
. 1–3 hours 5–10 hours 10–12 hours 24 hours
ANS: A
Pulmonary epithelial and alveolar macrophages are partly responsible for the production of inflammatory mediators in response to harmful ventilator strategies. This can occur within 1– 3 hours of initiation of ventilation. 13. In what areas of the lung are ventilation and perfusion best matched during spontaneous
ventilation in the supine position? Apices of the lungs Nondependent anterior lung areas Dependent posterior lung areas Basilar segments of lower lobes
a. b. c. d.
ANS: C
The dependent lung areas receive a higher portion of ventilation and perfusion. 14. In a mechanically ventilated patient who is receiving lorazepam and succinylcholine, the
diaphragm moves in which of the following ways?
a. A b. B c. C
d. D ANS: D
With sedation and paralysis sufficient to block spontaneous breaths, positive pressure ventilation displaces the diaphragm to the nondependent regions of the lung. 15. Preservation of spontaneous breathing during mechanical ventilation favors the distribution of
gas to which areas of the lung? a. Peribronchial area b. Upper airway c. Lung periphery d. Central airways ANS: C
The distribution of gas during spontaneous ventilation favors the dependent lung areas and also appears to favor the periphery of the lung closest to the moving pleural surfaces. The peripheral areas receive more ventilation than the central areas. However, during a positive pressure breath with passive inflation of the lung (paralysis), the central, upper airway, or peribronchial portions of the lung are preferentially filled with air. 16. Which of the following mechanically ventilated patients shows clinical signs of
hypoventilation? A patient who is cool to the touch and has negative T waves on the ECG A patient who has twitchy extremities and also atrial flutter on the ECG A patient who is anxious and hypertensive and has elevated T waves on the ECG A patient who has cool, twitchy extremities and also low, rounded T waves on the ECG
a. b. c. d.
ANS: C
Anxiety and hypertension (mild to moderate acidosis) are clinical signs of hypoventilation, along with elevated T waves on an ECG. Patients with hyperventilation are cool to the touch, have twitchy muscles from hypokalemia, and have low, rounded T waves, atrial flutter, or negative T waves on the ECG. 17. Which of the following mechanically ventilated patients shows clinical signs of
hyperventilation? a. A patient who has hot skin and also long P-R intervals on the ECG b. A patient who has cool skin and also shows paroxysmal tachycardia on the ECG c. A patient who is hypertensive and agitated and has S-T segment depression on the
ECG d. A patient who is hypotensive and dyspneic and has widened QRS complexes on
the ECG ANS: B
Cool skin and paroxysmal tachycardia are signs of decreased PaCO2. All the other answers are signs of hypoventilation. 18. Prolonged ventilator-induced hyperventilation can lead to which of the following? a. Hypokalemia b. Hyperkalemia c. Increased ICP
d. Headaches ANS: A
Reduced hydrogen ion concentrations in the blood are often accompanied by hypokalemia. The other answers are problems that hypoventilation can induce. 19. The RT assesses the flow–time scalar from an apneic patient mechanically ventilated in the
VC-CMV mode. The most appropriate action for this patient is to do which of the following?
a. b. c. d.
Decrease the set flow rate. Reduce the set ventilator rate. Increase the inspiratory time. Decrease the set tidal volume.
ANS: B
Because the patient is apneic, all the breaths are time triggered. The flow–time scalar shows that the ventilator rate is 40 breaths/min. The scalar also shows that air trapping is present. To alleviate this problem, the ventilator rate must be reduced to an acceptable level, such as 12– 14 breaths/min. 20. What is the minimum range of time constants necessary for the lungs to empty 98% of the
inspired volume? 1–2 2–3 3–4 4–5
a. b. c. d.
ANS: C
An expiratory time of at least 3–4 time constants is needed for the lungs to empty 98% of the inspired volume. 21. The acceptable lower limit of PaO2 for a mechanically ventilated patient with ARDS is which
of the following? 50 mm Hg 60 mm Hg 70 mm Hg 80 mm Hg
a. b. c. d.
ANS: B
The lower limits of permissive hypoxemia remain controversial. However, most clinicians agree that a target of PaO2 = 60 mm Hg and SpO2 = 90% are acceptable lower limits. 22. The combination of
absorption atelectasis. a. High tidal volumes, FIO2 > 0.4 b. High tidal volumes, FIO2 0.7
and
increases the risk for
c. Low tidal volumes, FIOs > 0.5 d. Low tidal volumes, FIO2 > 0.7 ANS: D
High oxygen concentrations (>70% oxygen) lead to rapid absorption atelectasis, particularly in hypoventilated lung units. 23. Assessment of a mechanically ventilated patient reveals use of accessory muscles and a
respiratory rate of 26 breaths/min. The mode is CPAP with 5 cm H2O and an FIO2 of 0.4. The most appropriate action is which of the following? a. Return the patient to full ventilatory support. b. Add pressure support to the CPAP. c. Increase the CPAP to 8 cm H2O. d. Deflate the cuff of the ET tube. ANS: B
This patient is suffering from an increased WOB, as evidenced by the use of accessory muscles and elevated respiratory rate. Adding pressure support will decrease the patient’s WOB by eliminating the airway resistance caused by the ET tube. Returning the patient to full ventilatory support before trying pressure support may add time to the patient’s length of stay on the ventilator. Increasing the CPAP is not appropriate, because there is no evidence of hypoxemia. Deflating the cuff would negate the CPAP and also increase the risk for ventilatorassociated pneumonia. 24. A patient with asthma is being ventilated in PSV, 5 cm H2O, with CPAP of 5 cm H2O. The
patient has chest wall retractions on most breaths and appears to have an increased WOB. The following graphic occurred the entire time the respiratory therapist was assessing the patient. What does this graphic demonstrate?
a. b. c. d.
Trigger asynchrony Mode asynchrony PEEP asynchrony Cycle asynchrony
ANS: A
The flow–time scalar shows that some breath initiations made by the patient are not triggering the ventilator; this is known as trigger asynchrony. In this particular patient, it could be caused by auto-PEEP. Patients experiencing asthmatic episodes have increased airway resistance, which can lead to auto-PEEP, which can affect the ventilator’s ability to sense the patient’s efforts.
25. When setting up a patient on volume ventilation with constant flow, the initial flow setting
should be 50 L/min 60 L/min 70 L/min 80 L/min
.
a. b. c. d.
ANS: D
An initial flow of 80 L/min typically is suggested when setting up a patient on volume ventilation with a constant flow. The pressure–time scalar should be evaluated for its appearance to ensure an appropriate flow rate. 26. The pressure–time scalar of a patient with COPD who is receiving PSV shows positive
deflection toward the end of inspiration. The most appropriate way to alleviate this is to do which of the following? a. Increase the PSV level. b. Decrease the PSV level. c. Increase the flow cycle percentage. d. Decrease the flow cycle percentage. ANS: C
This patient has cycle asynchrony. The positive deflection at the end of inspiration is caused by active exhalation. A patient with COPD needs a short inspiratory time and a long expiratory time. If the patient shows active exhalation before the end of inspiration, inspiration is too long. In PSV, inspiration ends when the flow cycle percent setting is reached. Increasing the flow cycle percentage will cause the ventilator to end-inspiration earlier, thus allowing a longer time for expiration. 27. A patient receiving pressure controlled–continuous mandatory ventilation (PC-CMV) has
initial arterial blood gas (ABG) findings as follows: PaO2 of 101 mm Hg, partial pressure of carbon dioxide in the arteries (PaCO2) of 60 mm Hg, and pH of 7.30. The respiratory therapist should a. increase minute ventilation to this patient. b. decrease pressure setting. c. change the ventilation mode. d. increase the minute ventilation to this patient very gradually over the next several days. ANS: A
The kidneys normally can compensate for respiratory acidosis within 18–36 hours. Obviously, it is desirable for the problem to be corrected by increasing alveolar ventilation rather than waiting for renal compensation. Increasing ventilation can be accomplished by increasing the VT or mandatory rate. 28. Which of the following increases the risk for a patient developing auto-PEEP?
1. Chronic obstructive airway disease 2. Low minute ventilation 3. Over the age of 60 years 4. Increased airway resistance a. 1 and 3 only
b. 2 and 4 only c. 1, 3, and 4 only d. 2, 3, and 4 only ANS: C
The following factors increase the risk for auto-PEEP • Chronic obstructive airway disease • High minute ventilation (more than 10 to 20 L/min) in ventilated patients • Age greater than 60 years • Increased airway resistance (e.g., small ET size, bronchospasm, increased secretions, mucosal edema) • Increased lung compliance (longer time constants) • High respiratory frequency • High inspiratory to expiratory ratios, that is short TE (e.g., 1:1 and 2:1); low inspiratory flow • Increased VT, particularly with airflow obstruction
Chapter 18: Troubleshooting and Problem Solving Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. When an alarm is activated on a ventilator, the respiratory therapist’s first priority is to a. b. c. d.
. assess the patient’s level of consciousness. ensure adequate ventilation and oxygenation. assess lung compliance and airway resistance. ensure that bilateral and equal breath sounds are present.
ANS: B
Patient safety is the foremost obligation of the respiratory therapist. Whenever an alarm activates on a ventilator, the respiratory therapist first should make sure the patient is adequately ventilated and oxygenated. To do this, the respiratory therapist can assess the patient’s level of consciousness, use of accessory muscles, and chest wall movements; determine whether bilateral breath sounds are present; and evaluate the heart rate and SpO2. 2. Removing a patient from a ventilator to ventilate manually can lead to which of the
following? 1. Barotrauma 2. Lung derecruitment 3. Increased airway resistance 4. Ventilator-acquired pneumonia a. 1, 2, and 3 only b. 1, 2, and 4 only c. 2, 3, and 4 only d. 3 and 4 only ANS: B
Removing a patient from the ventilator for manual ventilation can inadvertently cause barotrauma by using excessive pressure during ventilation (>40 cm H2O). Disconnecting a patient who is being ventilated with a high level of PEEP (15–25 cm H2O) can cause derecruitment of the lung. Disconnection of the ventilator can cause contamination of the patient’s airway, increasing the patient’s risk for developing ventilator-associated pneumonia. 3. A 68-year-old woman was admitted to the ICU with pneumonia and was intubated when she
developed progressive hypoxemia. She has been on the ventilator for 5 days and has been tolerating this therapy well. The patient has suddenly become severely agitated and appears to be fighting the ventilator. The ventilator’s high-pressure alarm is sounding continuously. The respiratory therapist disconnects the patient from the ventilator and begins manual ventilation with 100% oxygen and PEEP. The resuscitator bag is difficult to squeeze, breath sounds are present on the left with no adventitious sounds and absent on the right side, and percussion reveals hyperresonance over the right side. The most appropriate action to address this situation is which of the following? a. Pull the endotracheal tube back until bilateral breath sounds are heard. b. Administer a bronchodilator and suction the endotracheal tube.
c. Extubate the patient and reintubate with a larger endotracheal tube. d. Insert a 14-gauge needle in the second intercostal space, midclavicular line, right
side. ANS: D
If the endotracheal tube had slipped into the right main-stem bronchus, breath sounds would be heard on the right side and not on the left. The absence of breath sounds on the right side indicates that the endotracheal tube has not slipped into the right main-stem bronchus. No adventitious breath sounds are heard over the left lung, the patient has no history of bronchospasm, and no wheezing is heard—this essentially eliminates bronchospasm as the problem. The patient had been tolerating mechanical ventilation well for 5 days; therefore, the ET tube is not too small. The presence of auto-PEEP would cause hyperresonance to percussion bilaterally. The patient apparently has a pneumothorax on the right side, as evidenced by the absence of breath sounds and hyperresonance to percussion on that side. 4. The respiratory therapist is called to the bedside of a patient mechanically ventilated in the
VC-CMV mode because the low pressure, low exhaled tidal volume, and low exhaled minute volume alarms all have activated. Which of the following could be the cause of this situation? a. Patient biting the endotracheal tube b. Rupture of the endotracheal tube cuff c. Slipping of the endotracheal tube into the right mainstem d. Plugging of the airways by airway secretions and mucus ANS: B
With rupture of the ET tube cuff, volume escapes the system rather than being delivered to the patient. This activates the low pressure alarm and eventually leads to activation of the low tidal volume and low minute volume alarms. All the other options would activate the highpressure alarm. 5. The initial step in the management of patient-ventilator asynchrony is which of the following? a. Lower the high-pressure alarm setting. b. Check the endotracheal tube cuff pressure. c. Ventilate the patient with a manual resuscitator bag. d. Check the low and high-pressure alarm settings. ANS: C
If the patient is in severe distress, the first step is to disconnect the patient from the ventilator and carefully ventilate the patient using a manual resuscitation bag. 6. At 1030 the respiratory therapist is called to the bedside of a patient being mechanically
ventilated with VC-IMV. The patient is a 55-kg female who has been intubated with a size 8 endotracheal tube. Currently, the ET tube is located 20 cm at the gum line. During spontaneous breathing, the patient shows lack of coordinated chest wall movement, and the respiratory therapist notes some retraction of the intercostal spaces. The respiratory therapist performs a system check. The current and past few patient-ventilator system checks reveal the following information: Time 0430 0640 0835 1030 PIP (cm H2O) 28 31 34 41 Pplat (cm H2O) 18 21 19 20 The most appropriate action to take in this situation is which of the following? a. Deflate the cuff and reposition the endotracheal tube.
b. Request that the patient receive haloperidol and midazolam. c. Administer albuterol via an inline metered-dose inhaler. d. Switch the mode to PC-IMV and increase the rate. ANS: C
The lack of coordinated chest wall movement, the intercostal retractions, and the increased transairway pressure (seen at 1030) indicate bronchospasm. This can be confirmed by auscultating the patient’s chest. The patient should be suctioned before receiving the bronchodilator to remove any mucus. The sudden onset rules out an insidious increase in mucus. The ET tube is properly placed at the 20-cm mark and therefore does not require repositioning. This patient is not displaying any evidence of agitation, delirium, or anxiety; therefore, administration of haloperidol and midazolam is not appropriate in this situation. There is also no evidence of a need to change from volume to pressure control or to increase the set rate at this time. 7. A patient with a past medical history of COPD was placed on a ventilator after upper
abdominal surgery for a serious wound infection. Although the patient was medically stable, a tracheostomy was performed 2 weeks later because the patient was unable to be weaned from the ventilator. The patient is on VC-CMV, rate = 12, VT = 700 mL, FIO2 = 40%, PEEP = 5 cm H2O, with an HME. The respiratory therapist notes that the patient is assisting at a rate of 18 and has bilaterally decreased breath sounds in the bases. The respiratory therapist suctions a moderate amount of very thick, tenacious yellow sputum from the tracheostomy tube. What action should the respiratory therapist take? a. The HME should be replaced with an active heated humidifier system. b. No action is necessary, because there seems to be no patient problem. c. The patient should be suctioned on a regular schedule instead of when needed. d. PEEP and the FIO2 should be increased, and diuretic and positive inotropic agents should be administered. ANS: A
This patient seems to have a secretion problem, as evidenced by the very thick, tenacious yellow sputum suctioned from the ET tube. The thickness of the sputum indicates drying of the secretions. To alleviate this problem, the HME should be replaced with a heated humidification system. 8. An intubated patient is receiving mechanical ventilation with the following settings: VC-
CMV, rate = 18, VT = 850 mL (10 mL/kg), PEEP = 5 cm H2O, flow rate = 40 L/min. The patient is sedated and is not assisting the ventilator. During a patient-ventilator system check, the respiratory therapist observes the following ventilator graphic:
The respiratory therapist should do which of the following? Decrease the flow rate. Increase the PEEP. Decrease the rate. Increase the VT.
a. b. c. d.
ANS: C
The figure clearly shows air trapping, as evidenced by failure of the expiratory portion of the curve to return to zero. Auto-PEEP should be suspected whenever flow does not return to baseline in the flow–volume loop. Efforts to reduce auto-PEEP can be aided by reducing the inspiratory time, minute ventilation, and Raw. Decreasing the rate in this case would decrease the minute ventilation. Decreasing the flow rate would increase the inspiratory time, worsening the air trapping, and auto-PEEP. Increasing PEEP may make it easier for the patient to trigger the ventilator, but it would not reduce the air trapping. Increasing the VT would worsen the air trapping. 9. Reduction of preload and afterload is important in the management of which of the following? a. Pulmonary embolism b. Dynamic hyperinflation c. Cardiogenic pulmonary edema d. Noncardiogenic pulmonary edema ANS: C
Cardiogenic pulmonary edema and heart failure often can be managed successfully with medications that reduce preload, increase contractility, and reduce afterload; such medications include furosemide (Lasix), digoxin (Lanoxin), enalaprilat (Vasotec), and morphine. 10. An increased arterial-to-end tidal partial pressure CO2 gradient can help identify which of the
following? Pulmonary embolism Dynamic hyperinflation Cardiogenic pulmonary edema Noncardiogenic pulmonary edema
a. b. c. d.
ANS: A
Capnographic findings can provide a clue to the presence of a PE. A decrease in the end-tidal carbon dioxide (PetCO2) value compared with previous readings and a widening of the arterialto-end tidal partial pressure CO2 gradient (P[a-et]CO2) may suggest the presence of an embolus. 11. The respiratory therapist enters the room of an intubated and mechanically ventilated patient
to find the low pressure, low exhaled volume, and low VE alarms active. The ventilator circuit is connected to the patient’s endotracheal tube. This situation could be caused by which of the following? a. Improper flow rate and flow pattern b. Poorly responsive internal demand valve c. Migration of the ET tube into the upper airway d. The patient is continuing to actively inhale ANS: C
A combination of low pressure, low exhaled volume, and low VE alarms indicates a leak in the patient-ventilator system. This can be caused by migration of the ET tube into the upper airway. Because there is no longer a seal, gas does not travel into the lungs. Active inhalation may activate the low pressure alarm, but it would not activate the low volume and low VE alarms. On the contrary, there may be more volume than set on current ventilators. 12. A patient is intubated and set up on VC-CMV. After stabilization and suctioning of the ET
tube, the peak inspiratory pressure (PIP) is 25 cm H2O. The low pressure and high-pressure alarms should be set at cm H2O and cm H2O, respectively. a. 5; 35 b. 10; 30 c. 12; 40 d. 15; 35 ANS: D
The low pressure alarm should be set 5–10 cm H2O below the PIP, and the high-pressure alarm should be set about 10 cm H2O above the PIP. Therefore, with a PIP of 25 cm H2O, the low pressure alarm should be set at 15–20 cm H2O and the high-pressure alarm at 35 cm H2O. 13. The respiratory therapist enters the room of an intubated and mechanically ventilated patient
to find the high pressure, low exhaled volume, and low VE alarms active. This situation could be caused by which of the following? a. Improper flow rate and flow pattern b. Migration of the ET into the upper airway c. The patient is out of synchrony with the ventilator. d. The ventilator has an internal malfunction. ANS: C
A high-pressure alarm may also be triggered when a patient actively breathes out of synchrony with the ventilator. The PIP rises if the patient actively exhales while the ventilator is in the inspiratory phase, and this can activate the high-pressure alarm. 14. The respiratory therapist is assessing a mechanically ventilated patient for whom the high-
pressure alarm is active and the flow–volume loop shows the following:
The action that could alleviate this problem is which of the following? Place a bite block into the patient’s mouth. Perform a recruitment maneuver and increase PEEP. Administer a fast-acting bronchodilator and suction the ET tube. Insert a 14-gauge needle into the second intercostal space, midclavicular line, and
a. b. c. d.
right side. ANS: C
The flow–volume loop shows increased expiratory resistance; this plus activation of the highpressure alarm indicates increased airway resistance. Increased airway resistance can be caused by bronchospasm, which can be alleviated by a bronchodilator and suctioning. Although a patient biting the tubing would cause a high-pressure alarm, no or very little volume would enter the patient, and the flow–volume loop would not be as large. The flow– volume loop is not indicative of low compliance, which would necessitate a recruitment maneuver and increased PEEP. The expiratory flow would not be “scooped out” if low compliance were a problem. Because the signs indicate increased airway resistance, needle decompression is not appropriate. 15. Which of the following can activate an apnea alarm? a. Secretions b. Auto-PEEP c. Loss of PEEP d. Active inhalation ANS: B
In a spontaneous mode, the presence of auto-PEEP can cause the patient difficulty in triggering the ventilator. As a result, the patient’s efforts can go undetected, and the ventilator misinterprets this as apnea. 16. The graphics below indicate which of the following conditions?
a. b. c. d.
Auto-PEEP Active exhalation Inadequate flow setting Increased expiratory resistance
ANS: C
Inadequate flow during mechanical ventilation is shown in the figure on the pressure–time graphic by the concave pressure tracing while the flow curve is constant. Auto-PEEP would be evident on the flow graphic when the exhaled flow does not return to zero before the beginning of the next breath. Active exhalation would be evident on the pressure graphic as a peak at the end of inspiration. Increased airway resistance would show as the exhaled flow not returning all the way to zero by the time the next breath begins. 17. The following two graphic loops show which of the following conditions?
a. b. c. d.
Leak in the patient-ventilator circuit Increased airway resistance Decreased lung compliance Active exhalation
ANS: A
Because the expiratory volume does not return to zero in these graphics, a leak is present in the patient-ventilator circuit. Increased airway resistance would show as a scooped-out expiratory flow on the flow–volume loop, which may not end before the next breath. Decreased lung compliance would show as a “duck bill” on the pressure–volume loop. Active exhalation would make the volume tracing drop below zero. 18. The flow–volume loop below is representative of which of the following conditions?
a. b. c. d.
System leak Intrinsic PEEP Inadequate flow Active exhalation
ANS: B
The expiratory flow in this loop does not return to zero. This shows that auto-PEEP or intrinsic PEEP is present. 19. The flow–time curve shows small oscillations after the peak flow rate has been reached. The
respiratory therapist can alleviate this by making which of the following ventilator adjustments? a. Increase the set flow rate. b. Increase the inspiratory time. c. Decrease the inspiratory rise time. d. Increase the inspiratory rise time. ANS: D
The oscillations on the flow–time curve represent a phenomenon known as ringing, spiking, or overshoot. This is due to a nonsmooth breath delivery. Increasing the inspiratory rise time smooths out the breath delivery by increasing the time it takes for the ventilator to reach the set flow rate. 20. The graphic below for a patient receiving mechanical ventilation shows which of the
following conditions?
a. b. c. d.
Leak in the circuit Active inspiration Active exhalation Intrinsic PEEP
ANS: B
Before the delivery of a mandatory breath (constant flow, volume-controlled continuous mandatory ventilation [VC-CMV]), patient effort reaches the trigger threshold, and a normal breath is delivered (breath on left). The second breath (right) is patient triggered, but the pressure curve (arrow) is concave because of the patient’s active attempt to inhale. 21. Use of an externally powered, small-volume nebulizer for aerosol delivery during partial
ventilatory support with PSV may cause which of the following? 1. High VT alarm activation 2. Triggering difficulties 3. Low pressure alarm activation 4. Ventilator inoperative alarm a. 1 and 2 only b. 2 and 3 only c. 3 and 4 only d. 1 and 4 only ANS: A
When a continuous flow nebulizer is placed between the patient and the sensing mechanism, the patient often finds it more difficult to generate the effort to trigger the ventilator. High VT delivery can occur when externally powered, small-volume nebulizers are used for aerosol delivery. 22. During ventilation with VC-CMV, pleural drainage leaks sometimes can be compensated for
by increasing which of the following? a. The number of chest tubes b. The set tidal volume c. The set pressure limit
d. The set peak inspiratory flow ANS: B
Compensation for pleural leaks sometimes can be accomplished by increasing volume delivery to the patient. The amount of air leaking through the pleural drainage system can be determined by comparing the inspiratory and expiratory VT. 23. A mechanically ventilated patient with COPD is receiving partial ventilatory support with
PSV. The respiratory therapist notes a sudden rise at the end of each breath on the pressure– time graphic. What action should the respiratory therapist take at this time? a. Change the mode to PRVC. b. Change the mode to VC-CMV. c. Lower the flow cycle setting. d. Adjust the pressure support level. ANS: C
Asynchronous breathing may be seen in patients with COPD when PSV is used. COPD patients often show active short inspirations and active long expirations. If the patient begins to exhale actively during the inspiratory phase of PSV, the flow may not drop to the necessary cycling value to end-inspiration on the pressure supported breath, resulting in a sudden rise in the scalar at the end of the breath. This problem can be prevented in these patients by using a ventilator with adjustable flow-cycling characteristics. 24. The respiratory therapist is performing a patient-ventilator system check on a patient who was
in a motor vehicle accident 2 days earlier. The therapist gathers the following information from the flow sheet: Day/Time 1/25:1720 1/26:0830 1/26:1840 1/27:0650 Mode VC-CMV VC-CMV VC-CMV VC-CMV PIP (cm H2O) 21 28 32 41 Pplat (cm H2O) 18 25 29 38 Which condition most likely has produced the changes reflected in these data? a. Bronchospasm b. Abdominal distention c. Secretion retention d. Mucosal edema ANS: B
The difference between the PIP and Pplat is consistent throughout the documentation (3 cm H2O). The Pplat has increased over the course of the 36 hours, from 18 to 38 cm H2O. This indicates a decrease in static lung compliance. Causes of this condition include ARDS, pneumonia, pneumothorax, pleural effusions, abdominal distention, and ascites. Bronchospasm, secretion retention, and mucosal edema would increase the transairway pressure (PIP Pplat). 25. The high-pressure alarm activates on a patient receiving mechanical ventilatory support. The
patient is tachycardic and tachypnic with absent breath sounds on the right side. Which of the following condition(s) could be the cause? 1. Pneumothorax 2. Pulmonary edema 3. Disconnection from the ventilator 4. Increased airway resistance
a. b. c. d.
1 only 4 only 1, 2, and 3 only 1 and 4 only
ANS: A
Pneumothorax is another possible problem that must be detected during positive pressure ventilation (PPV) and treated quickly. Pneumothorax can be recognized as increased WOB if a patient is conscious. For example, the patient may demonstrate nasal flaring, use of accessory muscles, uneven chest wall movement, and absence of breath sounds on the affected side. Auscultation and percussion of the chest, cardiovascular assessment, and ventilating pressure evaluations usually can distinguish a pneumothorax from other problems. 26. You are called into a patient’s room by the nurse because blood is spurting from the
tracheostomy site, which was placed 2 weeks ago. The patient is receiving mechanical ventilatory support and has a history of liver failure and CHF. Which of the following conditions is the most likely cause? a. Acute pulmonary edema b. Rupture of the innominate artery c. Pulmonary hemorrhage d. Pneumothorax ANS: B
Rupture of the innominate artery is a potentially serious airway complication and the mortality rate for this condition is high. It usually is seen in the first 3 weeks after a tracheostomy. The immediate indication is blood spurting from the tracheotomy site.
Chapter 19: Basic Concepts of Noninvasive Positive Pressure Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Negative pressure ventilators cause air to enter the lungs by increasing
pressure. transairway transpulmonary transrespiratory transthoracic
a. b. c. d.
ANS: B
Transpulmonary pressure maintains alveolar inflation due to the decrease in pleural pressure caused by the negative pressure surrounding the chest wall. Positive pressure ventilators cause air to move into the lungs by increasing the pressure in the upper airways and in the conductive airways. Changes in transpulmonary pressure result in corresponding changes in alveolar volume. The transairway pressure is the gradient that produces airway movement in the conductive airways and represents the pressure caused by resistance to gas flow in the airways. The transrespiratory pressure is responsible for gas flow into and out of the alveoli during breathing. The transthoracic pressure is the pressure across the chest wall. It represents the pressure necessary to expand or contract the lungs and chest wall together. 2. A patient with acute cardiogenic pulmonary edema (ACPE), as evidenced by pink, frothy
secretions, arrives in the emergency department (ED) by ambulance with a nonrebreather mask at 15 L/min. An arterial blood gas sample is drawn in the ED while the patient is on the nonrebreather mask; the values are: pH = 7.50, PaCO2 = 28 mm Hg; PaO2 = 43 mm Hg; SaO2 = 84%; HCO = 24 mEq/L. After evaluating the situation, the respiratory therapist should suggest which of the following therapies? a. IPPB with supplemental oxygen b. Mask CPAP with supplemental oxygen c. Postural drainage to clear the secretions d. NIV via nasal mask with postural drainage ANS: B
The current recommendation for ACPE is for CPAP to be used initially. NIV should be used only in patients who were hypercapnic and continue to be hypercapnic in spite of the CPAP. This patient is not hypercapnic at this time; therefore, mask CPAP is the appropriate therapy. IPPB is not appropriate because the positive effects of the therapy will be lost after a few minutes off the therapy. 3. A patient has acute pulmonary edema from left-sided heart failure and acute hypoxemic
respiratory failure that has not responded to conventional pharmacological and oxygen therapy. As the next line of therapy, the respiratory therapist should recommend which of the following? a. Noninvasive positive pressure ventilation b. Continuous positive airway pressure c. Intubation and mechanical ventilation
d. Bronchial hygiene therapy ANS: B
The current recommendation for ACPE is for CPAP to be used initially. NIV should be used only in patients who were hypercapnic and continue to be hypercapnic in spite of the CPAP. 4. One of the physiological goals of NIV in acute respiratory failure is to improve gas exchange
by a. b. c. d.
. resting the respiratory muscles decreasing the effect of secretions increasing right ventricular preload decreasing the functional residual capacity
ANS: A
The physiological goal in acute respiratory failure is to improve gas exchange by resting the respiratory muscles and increasing alveolar ventilation. 5. The primary goal of NIV in the acute care setting is to do which of the following? a. Improve sleep quality. b. Decrease muscle fatigue. c. Avoid invasive ventilation. d. Eliminate nocturnal hypopnea. ANS: C
Avoidance of intubation and invasive ventilation is the primary goal of NIV in the acute care setting. The other options are benefits of NIV, but they are not the primary goal in the acute care setting. 6. Patients with chronic hypoventilation disorders typically need a minimum of
hours of NIV to experience improved quality of life. a. 2–4 b. 4–6 c. 6–8 d. 8–10 ANS: B
Nocturnal use of NIV (4–6 hours) can have certain clinical benefits for patients with chronic hypoventilation disorders. The most significant of these are improvement of symptoms associated with chronic hypoventilation and an improved quality of life. 7. NIV is considered the standard of care for the treatment of which of the following? a. COPD exacerbation b. Asthma exacerbation c. Noncardiogenic pulmonary edema d. Community-acquired pneumonia ANS: A
NIV is currently considered the standard of care for the treatment of COPD exacerbation in selected patients. Specific criteria for the selection of asthma patients to receive NIV have not yet been developed. NIV may be appropriate in patients who do not respond to conventional treatment methods. Unless a patient has COPD and CAP, caution should be used when treating patients with NIV. Mask CPAP is the standard of care for ACPE.
8. A 75-year-old man with a long history of COPD is brought to the emergency department with
shortness of breath. He has a persistent, productive cough with green purulent sputum, cyanosis of the lips and extremities, and is uncooperative. His arterial blood gas values on 2 L/min by nasal cannula are: pH = 7.25; PaCO2 = 90 mm Hg; PaO2 = 38 mm Hg; SaO2 = 59%; HCO = 38 mEq/L. The most appropriate action at this time is which of the following? IPPB Mask CPAP NIV via full face mask Invasive mechanical ventilation
a. b. c. d.
ANS: D
This patient meets the blood gas criteria for moderate to severe respiratory failure and therefore needs ventilatory support, as evidenced by the pH <7.35 and the PaCO2 >45 mm Hg; the PaO2/FIO2 is estimated at 38/0.28 = 136. This patient is at risk for failure of NIV because he is uncooperative (probably due to hypoxia) and has excessive secretions, as evidenced by his persistent productive cough. 9. A 61-year-old female was admitted last night with shortness of breath. She currently is alert
and oriented but very anxious. Her latest arterial blood gas values, on a nasal cannula at 3 L/min, show: pH = 7.39; PaCO2 = 41 mm Hg; PaO2 = 40 mm Hg; SaO2 = 74%; HCO - = 24 mEq/L. Breath sounds are decreased throughout with fine late crackles on inspiration. The current chest X-ray shows an enlarged heart with bilateral vascular congestion. The most appropriate therapy for this patient is . a. nasal cannula b. mask CPAP c. invasive ventilation d. nonrebreather mask ANS: B
The arterial blood gas values for this patient show refractory hypoxemia, as evidenced by the PaO2 of 40 mm Hg while receiving supplemental oxygen. The breath sounds indicate pulmonary edema. This finding is supported by the chest X-ray, which shows bilateral vascular congestion and an enlarged heart. These findings are consistent with acute cardiogenic pulmonary edema. The most appropriate therapy is mask CPAP. 10. A patient with acute cardiogenic pulmonary edema is to be placed on CPAP. What should the
initial setting be? 3–5 cm H2O 5–7 cm H2O 10–12 cm H2O 15–20 cm H2O
a. b. c. d.
ANS: C
The current recommendation is that CPAP at 10–12 cm H2O be used initially in the treatment of ACPE.
11. A 62-year-old male patient with COPD is being seen in the pulmonary clinic for dyspnea at
rest and daytime hypersomnolence. The patient has been hospitalized three times in the past year for COPD exacerbations and once for pneumonia. He currently uses 2 L/min oxygen from a concentrator all the time. The patient reports that he is able to sleep only about 2 hours each night and that he has a headache every morning. Which of the following should be recommended to the physician? a. Chest cuirass b. Nocturnal NIV c. Nocturnal CPAP d. Tracheostomy and ventilation ANS: B
This patient shows signs of nocturnal hypoventilation and poor sleep quality, as evidenced by the daytime hypersomnolence, dyspnea, and morning headache. This patient should be assessed further for the use of nocturnal NIV by testing for oxygen saturation overnight. 12. A patient who was diagnosed 1 year ago with amyotrophic lateral sclerosis is being seen in his
primary care physician’s office. The patient is complaining of fatigue and inability to concentrate at work. The patient’s FVC is 45% of predicted, the PaCO2 is 47 mm Hg, and the MIP is 54 cm H2O. Which of the following should be considered for this patient? a. Continuation of current therapy b. Supplemental home oxygen c. Nocturnal CPAP d. Nocturnal NIV ANS: D
Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that eventually leads to total paralysis. This patient has degenerated to the point where he meets the physiological criteria for the use of NIV, as evidenced by the FVC below 50% of predicted, the MIP below 60 cm H2O, and the PaCO2 above 45 mm Hg. This patient needs to be monitored closely for loss of oropharyngeal muscle strength and ability to generate an effective cough. 13. To use CPAP successfully, a patient must have which of the following? a. Adequate PaO2 b. Secure artificial airway c. PaCO2 >40 mm Hg d. Adequate spontaneous ventilation ANS: D
To use CPAP successfully, a patient must be able to breathe spontaneously. 14. The variable that ends pressure support breaths from a pressure supported breath is
. a. b. c. d.
time flow pressure volume
ANS: B
Each pressure supported breath is flow triggered and flow cycled.
15. A patient in the subacute care unit is receiving NIV with a PTV system, with an IPAP of 10
cm H2O and an EPAP of 3 cm H2O. The patient’s latest arterial blood gas values reveal an increase in the PaCO2. The most appropriate action to take is which of the following? a. Increase the IPAP. b. Decrease the IPAP. c. Increase the EPAP and IPAP. d. Intubate and mechanically ventilate. ANS: C
The EPAP of 3 cm H2O is not providing enough continuous flow of gas through the system to minimize the rebreathing of CO2. Increasing both the EPAP and IPAP will provide enough flow to wash out the CO2 and keep the pressure support DIF consistent. 16. A homecare patient using NIV complains that when she puts on the NIV mask at night and
turns on the machine, “at first the gas feels like it is punching her in the face.” The patient is noncompliant with the NIV because of this. What action should the respiratory therapist take? a. Decrease the IPAP. b. Increase the EPAP. c. Decrease the flow trigger. d. Set the ramp and delay time. ANS: D
The PTV allows for adjustment of the ramp and delay time to enhance patient comfort. Ramp allows positive pressure to increase gradually over a set interval or delay time. 17. If oxygen is bled into each of the following portable PTVs at the same rate, which of the
following combinations will provide the highest oxygen concentration? a. Leak port at mask, oxygen bleed at mask, IPAP 8 cm H2O, EPAP 16 cm H2O b. Leak port at mask, oxygen bleed at machine outlet, IPAP 6 cm H2O, EPAP 18 cm
H2O c. Leak port in circuit, oxygen bleed at mask, IPAP 5 cm H2O, EPAP 10 cm H2O d. Leak port in circuit, oxygen bleed in circuit, IPAP 5 cm H2O, EPAP 15 cm H2O ANS: C
The highest oxygen concentration will occur when the IPAP and EPAP DIFs are lower. The lowest DIFFERENCE in this question is an IPAP of 5 cm H2O and an EPAP of 10 cm H2O. Also, if the leak port is in the circuit, higher oxygen concentrations are obtained when the oxygen is bled into the patient’s mask. 18. The leading cause of patient discomfort and noncompliance with NIV is which of the
following? Drying of nasal mucosa Mask type and fit Type of PTV Lack of an oxygen blender
a. b. c. d.
ANS: A
Excessive drying of the nasal mucosa as a result of using nasal CPAP or NIV is associated with nasal congestion and increased nasal resistance. This is a leading cause of patient discomfort and noncompliance with the prescribed therapy.
19. A patient with acute respiratory failure requires NIV. The patient is very dyspneic. Which of
the following patient interfaces is most appropriate? Nasal mask Mini mask Nasal pillows Oronasal mask
a. b. c. d.
ANS: D
The oronasal mask is used for patients with ARF, because acutely dyspneic patients tend to breathe more through the mouth as dyspnea increases. 20. Overtightening of the headgear straps for a nasal mask may lead to which of the following? a. Lack of an air leak b. Facial skin irritation c. Nasal air leak d. Hypersalivation ANS: B
Overtightened headgear straps can lead to redness and irritation of the skin and the potential for ulceration. Straps that are too tight may cause the mask to leak more. Nasal air leak is a disadvantage of mouthpieces, as is hypersalivation. 21. Which of the following NIV settings produces the greatest tidal volume, with all other
variables being equal (i.e., airway resistance and lung compliance)? IPAP = 20 cm H2O; EPAP = 8 cm H2O IPAP = 15 cm H2O; EPAP = 5 cm H2O IPAP = 12 cm H2O; EPAP = 6 cm H2O IPAP = 18 cm H2O; EPAP = 4 cm H2O
a. b. c. d.
ANS: D
If everything is equal, the largest tidal volume will be produced with the greatest pressure support DIF. 22. A 75-year-old, 5-foot, 7-inch female patient with an exacerbation of COPD is placed on the
following NIV settings: IPAP = 8 cm H2O, EPAP = 4 cm H2O, rate = 12 breaths/min, FIO2 = 0.3. The resulting VT is 255 mL. An arterial blood gas sample is drawn 1 hour later, and the results are: pH = 7.33, PaCO2 = 70 mm Hg, PaO2 = 58 mm Hg, HCO = 35 mEq/L. What action should the respiratory therapist take at this time? a. Increase the rate to 14 breaths/min. b. Increase the IPAP to 10 cm H2O. c. Intubate and mechanically ventilate the patient. d. Increase the IPAP to 10 cm H2O and the EPAP to 6 cm H2O. ANS: B
NIV was initiated at the appropriate settings for this patient; however, the arterial blood gas values show that the patient still has hypercapnia in addition to her chronic ventilatory failure. The current settings are yielding a VT of 4 mL/kg. The IPAP needs to be increased to maintain the exhaled VT at 5–7 mL/kg. This will decrease the PaCO2 to an acceptable DIF for this patient.
23. A 68-year-old, 5-foot, 10-inch male patient with acute-on-chronic respiratory failure due to
COPD has been placed on NIV with these settings: IPAP = 8 cm H2O, EPAP = 4 cm H2O, FIO2 = 0.28. The patient’s measured exhaled volume is 350 mL with a spontaneous respiratory rate of 24 breaths/min. The resulting arterial blood gas values are: pH = 7.27, PaCO2 = 77 mm Hg, PaO2 = 64 mm Hg, SaO2 = 88%, HCO = 36 mEq/L. What action should the respiratory therapist take at this time? a. Increase the FIO2 to 0.4. b. Increase the EPAP to 6 cm H2O. c. Increase the IPAP to 12 cm H2O. d. Decrease the EPAP to 2 cm H2O. ANS: C
This patient has an acute-on-chronic respiratory acidosis that has not been corrected by the NIV at the current settings. The resulting VT is 4.7 mL/kg, which is not enough to reduce the PaCO2 to an acceptable DIF for this patient (the pH should be about 7.37). Titrating the IPAP DIF to maintain an exhaled VT of 5–7 mL/kg can be accomplished by increasing the IPAP. 24. A patient with central sleep apnea uses a nasal mask with NIV at night. The patient complains
of nasal congestion. What action should the respiratory therapist take? Reduce the EPAP. Add a heated humidifier. Switch to a mouthpiece. Add a heat/moisture exchanger.
a. b. c. d.
ANS: B
NIV can cause excessive drying of the nasal mucosa, which has been associated with nasal congestion and increased nasal resistance. A heated humidifier can significantly reduce the dryness that causes congestion. Use of an HME is inappropriate, because it would lead to increased WOB. 25. Which of the following is the most efficient means of delivering a medicated aerosol during
NIV? Nebulizer placed between the leak port, located in the circuit, and the mask MDI placed between the leak port, located in the circuit, and the mask Use of both high inspiratory and high expiratory pressures MDI placed in the circuit with the leak port in the mask
a. b. c. d.
ANS: D
The efficiency of aerosol delivery is similar for a nebulizer and an MDI when the leak port is located in the circuit and the aerosol device is placed between the leak port and the mask. If the leak port is located in the mask, aerosol delivery is more efficient from an MDI than from a nebulizer, provided the MDI is actuated at the beginning of inspiration. Regardless of the device used, more aerosol is lost through the leak port during the exhalation phase of breathing. Increased aerosol delivery is also more likely when a high inspiratory pressure and a low expiratory pressure are used. 26. NIV has just been initiated on a patient in respiratory distress with an inspiratory positive
airway pressure (IPAP) of 12 cm H2O and an end-expiratory positive airway pressure (EPAP) of 5 cm H2O. Which of the following would indicate clinical improvement of the patient’s condition?
1. Decreased respiratory rate 2. Synchronization with the ventilator 3. Decreased inspiratory muscle activity 4. Decreased arterial oxygen saturation (SaO2) a. 1 and 2 only b. 1, 2, and 3 only c. 2, 3, and 4 only d. 2, 3, and 4 only ANS: B
Improvement in patient comfort is indicated by a decreased respiratory rate, decreased inspiratory muscle activity, and synchronization with the ventilator. 27. What determines the patient’s delivered tidal volume in all modes of bilevel positive pressure
ventilation? IPAP EPAP The gradient between the IPAP and EPAP Patient’s respiratory rate
a. b. c. d.
ANS: C
In all modes of bilevel positive pressure ventilation, the patient’s delivered VT depends on the gradient between the IPAP and EPAP, the inspiratory time, and the patient’s inspiratory effort and lung characteristics.
Chapter 20: Weaning and Discontinuation from Mechanical Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. All of the following patients are intubated and receiving mechanical ventilation. Which of
them is most likely to require slow liberation from mechanical ventilation? A patient who overdosed on diazepam A postoperative patient who had knee surgery A patient with a severe exacerbation of asthma A patient with chest contusions from a motor vehicle crash
a. b. c. d.
ANS: D
A large percentage of patients who need temporary mechanical ventilation do not require a gradual withdrawal process. Such patients include those receiving postoperative ventilatory support for recovery from anesthesia, treatment of uncomplicated drug overdose, and exacerbation of asthma. The patient with chest contusions from an accident has a higher risk for developing problems that will require a more gradual weaning process. 2. A patient is being weaned from invasive mechanical ventilation using VC-IMV. The
respiratory therapist reviews the following data from the past few hours. Time Set VT (mL) Spontaneous VT Set Rate (per Spontaneous (mL) min) Rate (per min) 0630 650 410 8 6 1020 650 400 6 10 1600 650 320 4 20 2200 650 250 2 32 What should the respiratory therapist recommend for this patient? a. Switch the mode to VC-CMV. b. Add and titrate pressure support. c. Extubate and place the patient on NIV. d. Increase the set rate to 8 breaths/min. ANS: B
The data demonstrate that as the set IMV was decreased, the patient’s spontaneous respiratory rate increased and the spontaneous tidal volume decreased. This shows that the patient’s work of breathing is excessive and most likely due to the resistance from the ventilator system, circuit, and artificial airway. Initiate pressure support and titrate the level to improve the spontaneous volume and decrease the spontaneous rate. Once the patient is stable, the pressure support may be weaned. 3. What ends inspiration in pressure support ventilation? a. Time b. Flow c. Volume d. Pressure ANS: B
Each pressure support breath is flow cycled. 4. At what pressure is pressure support not high enough to contribute significantly to ventilatory
support but is sufficient to overcome the work imposed by the ventilator system? a. 2 cm H2O b. 5 cm H2O c. 8 cm H2O d. 10 cm H2O ANS: B
When pressure support is reduced to about 5 cm H2O, the pressure level is not high enough to contribute significantly to ventilatory support. However, this level of support is usually sufficient to overcome the work imposed by the ventilator system (i.e., the resistance of the ET tube, trigger sensitivity, demand-flow capabilities, and the type of humidifier used). 5. Which mode of ventilation delivers the exact amount of pressure required to overcome the
resistive load imposed by the ET tube for the flow measured at the time? Automode Volume-targeted PSV Pressure support ventilation Automatic tube compensation
a. b. c. d.
ANS: D
ATC reduces the work of breathing associated with increased ET tube resistance. ATC is designed to deliver exactly the amount of pressure required to overcome the resistive load imposed by the ET tube for the flow measured at the time. In a sense, this is providing variable PSV with variable inspiratory flow compensation. Volume-targeted PSV maintains a target volume by varying the pressure support level. PSV provides an operator-selected set pressure for every spontaneous breath. The automode can switch between time-triggered mandatory breaths and patient-triggered, volume-targeted, pressure-limited breaths as long as the patient is breathing spontaneously. 6. The mode of ventilation that maintains a minimum VE by increasing or decreasing the amount
of support (VT or respiratory rate) given to the patient is volume support automatic tube compensation mandatory minute ventilation adaptive support ventilation
.
a. b. c. d.
ANS: C
In MMV, the ventilator automatically increases the level of support if the patient’s spontaneous ventilation decreases, thus maintaining a consistent minimum VE. Patients who regain the ability to breathe spontaneously can increase their own VE, and the machine automatically lowers support without the clinician having to change any specific ventilator settings. 7. Which of the following is considered a closed-loop mode used for weaning from mechanical
ventilation? a. Pressure support ventilation b. Adaptive support ventilation c. Continuous positive airway pressure
d. Intermittent mandatory ventilation ANS: B
ASV is a patient-centered method of closed-loop mechanical ventilation that increases or decreases ventilatory support based on monitored patient parameters. 8. A postoperative patient, still under anesthesia, is being ventilated with VC-CMV with
automode. After 2 hours, the patient is waking up and beginning to breathe spontaneously. The ventilator will respond by . a. switching to the pressure support mode b. switching to the volume support mode c. delivering time-triggered, pressure-limited breaths d. ensuring minimum mandatory minute ventilation ANS: B
If a postoperative patient is still recovering from the effects of anesthesia and the ventilator operator has selected volume-controlled continuous mandatory ventilation (VC-CMV) with automode as the operating mode, all breaths are mandatory (time triggered, volume limited, and time cycled). If the patient begins to trigger breaths, the ventilator switches to VS (patient triggered, pressure limited, and flow cycled with a volume target) and remains in this mode as long as the patient is breathing spontaneously. 9. The ACCP/SCCM/AARC task force recommends that a search for all possible causes that
may be contributing to ventilator dependence be undertaken in patients who require mechanical ventilation for longer than hours. a. 12 b. 24 c. 48 d. 72 ANS: B
This is the first recommendation for weaning a patient from mechanical ventilation established by the ACCP/SCCM/AARC task force. 10. Assess the following data obtained from the spontaneous breathing trials of four patients.
Which patient is most likely to be weaned successfully at this time? Spontaneous rate = 32 breaths/min, VT = 375 mL, PaO2 = 98 mm Hg, FIO2 = 0.4 Spontaneous rate = 15 breaths/min, VT = 450 mL, PaO2 = 87 mm Hg, FIO2 = 0.6 Spontaneous rate = 15 breaths/min, VT = 650 mL, PaO2 = 91 mm Hg, FIO2 = 0.28 Spontaneous rate = 12 breaths/min, VT = 680 mL, PaO2 = 79 mm Hg, FIO2 = 0.5
a. b. c. d.
ANS: C
Calculate the f/VT and PaO2/FIO2 for each patient. The patient with acceptable criteria has an f/VT of 23 and a PaO2/FIO2 of 325. 11. A 46-year-old male patient (IBW = 85 kg) who was injured in a motor vehicle crash has been
receiving invasive mechanical ventilation for 24 hours. The patient is awake, alert, and looks comfortable on the following settings: VC-IMV with pressure support of 5 cm H2O; set rate = 8 breaths/min; set VT = 500 mL; FIO2 = 0.4; PEEP = 5 cm H2O. A 10-minute spontaneous breathing trial (SBT) yields this information: f = 30 breaths/min, RSBI = 145, P0.1 = 10 cm H2O. What should the respiratory therapist suggest to the physician during patient rounds?
a. b. c. d.
Sedate the patient and place him on VC-CMV. Continue with the current ventilator settings. Switch to PC-CMV with a rate of 14 breaths/min. Decrease the mandatory SIMV rate to 4 breaths/min.
ANS: B
The RSBI is at a level that suggests the patient is not ready for weaning. An RSBI below 105 suggests that weaning is likely to be successful. The P0.1 is a measurement of the drive to breathe. The patient achieved 10 cm H2O, which indicates a high drive to breathe and suggests that weaning from mechanical ventilation is not likely to succeed. This information is a strong indicator that the patient should not begin active weaning at this time and should be continued on the original settings, because the patient was comfortable on those settings. 12. Calculate and determine the weanability of patients with this data: CD = 25 mL/cm H2O, PImax
= 28 cm H2O, PaO2 = 93 mm Hg, PAO2 = 158 mm Hg, and f = 22 breaths/min. 2—not weanable 19—weanable 32—not weanable 54—weanable
a. b. c. d.
ANS: B
Use the CROP formula: CROP = 13. Which parameter is used as the primary index of the drive to breathe? a. Airway occlusion pressure b. CROP index c. Maximum inspiratory pressure d. Rapid shallow breathing index ANS: A
The inspiratory drive to breathe is established by measuring the airway occlusion pressure (P0.1 [or P100]). 14. An SBT should not continue for longer than a. 30 b. 60 c. 120 d. 180
minutes.
ANS: C
SBTs typically last at least 30 minutes but no longer than 120 minutes. 15. In which patient would continued use of an artificial airway be necessary? a. A patient with upper airway burns and no peritubular leak b. A patient who tests positive for a peritubular leak c. A patient with bronchospasm and supplemental oxygen requirements d. A patient with a strong cough who expectorates moderate amounts of sputum ANS: A
A patient with upper airway burns may have upper airway inflammation that could obstruct the upper airways. The fact that the patient does not have a peritubular leak means that the airway caliber is not adequate. Extubation of this patient at this time would not be successful.
16. A recently extubated patient develops a partial upper airway obstruction, which causes stridor.
What action can the respiratory therapist take to improve the patient’s condition? Aerosolize 11.25 mg (2.25% solution) of racemic epinephrine. Put a nonrebreather mask on the patient. Place the patient on NIV. Suggest the use of lorazepam (Ativan).
a. b. c. d.
ANS: A
This patient has developed postextubation glottic edema and should be treated immediately with aerosolized racemic epinephrine. The patient also could be given steroids. A nonrebreather mask would not address the upper airway obstruction unless the mask is powered by heliox. This would allow time for the medical treatment to take effect. Use of an antianxiety drug is not indicated in this situation, because it would decrease the patient’s drive to breathe. Putting the patient on NIV would not address the patient’s immediate problem. 17. A female intubated patient has been weaned from full ventilatory support to PSV 5 cm H2O,
CPAP 5 cm H2O, and an FIO2 of 0.3. The patient is alert and oriented and doing well. The respiratory therapist performs a cuff leak test. The average peritubular leak is 70 mL. The respiratory therapist should recommend which of the following? a. Maintain the patient on the current settings and redo the cuff leak test in 24 hours. b. Increase the PSV to 10 cm H2O and maintain the CPAP and FIO2. c. Extubate the patient and place her on a heated aerosol generator with an FIO2 of 0.4. d. Pretreat the patient with steroids and/or racemic epinephrine before extubation. ANS: D
This patient is at high risk for developing stridor after extubation. Pretreatment with either racemic epinephrine and/or steroids would help reduce this risk. No change in ventilator parameters is called for in this situation. Extubating the patient and putting her on a heated aerosol would increase the risk for upper airway inflammation because of the heat. Waiting 24 hours when the patient is ready for extubation increases the patient’s risk for ventilatoracquired pneumonia. 18. A patient is extubated and placed on a cool, bland aerosol with 30% oxygen. Twenty minutes
post extubation, the respiratory therapist is called to assess the patient, who has shortness of breath. The respiratory therapist observes intercostal retractions, accessory muscle use, and a respiratory rate of 38 breaths/min. Stridor can be heard without a stethoscope, and the SpO2 has dropped from 97% to 85%. The patient is given an aerosolized racemic epinephrine treatment and reassessed. Accessory muscle use continues, intercostal retractions decrease slightly, and stridor is heard on auscultation. The patient’s respiratory rate is 30 breaths/min and the SpO2 is 88%. What should the respiratory therapist recommend? a. Reintubation and mechanical ventilation b. Heliox therapy and steroid administration c. Increase the FIO2 on the cool bland aerosol to 40% d. Use a nonrebreather mask with 15 L/min oxygen. ANS: B
The racemic epinephrine treatment improved the patient’s clinical status, as evidenced by a decrease in intercostal retractions, decrease in respiratory rate, and increase in SpO2. The patient’s stridor now is heard only on auscultation, whereas it was audible without a stethoscope before the racemic epinephrine. Heliox therapy would reduce the patient’s WOB further and allow time for the steroids to take effect. Because the patient improved, reintubation would only increase the risk for nosocomial pneumonia and is not warranted at this time. Increasing the FIO2 may help improve the patient’s SpO2, but it does not address the patient’s upper airway obstruction. A nonrebreather mask with 15 L/min oxygen would not help relieve the patient’s upper airway obstruction. 19. If a patient who has failed an SBT still meets the criteria for discontinuation of ventilation, an
SBT should be performed every 6 12 24 36
hours to determine weanability.
a. b. c. d.
ANS: C
If after failing an SBT the patient still meets the criteria for discontinuation of ventilation, another SBT should be performed every 24 hours. It is important to wait 24 hours before attempting another trial. Frequent SBTs over a single day are not helpful and can have serious consequences. Testing more frequently than every 24 hours offers no advantages. 20. Sixty minutes after a patient is extubated, an arterial blood gas sample is drawn; the results
are: pH = 7.20, PaCO2 = 60 mm Hg, PaO2 = 55 mm Hg, SaO2 = 80%, HCO3– = 23 mEq/L with a 2 L/min nasal cannula. The patient is SOB and complaining of chest pain. His blood pressure is 92/50 mm Hg. The most likely cause of this weaning failure is which of the following? a. Chronic obstructive pulmonary disease b. Acute left ventricular failure c. Ventilatory muscle weakness d. Hypophosphatemia ANS: B
Patients who do well for 30–60 minutes after extubation and then fail weaning because of acute respiratory acidosis, hypoxemia, hypotension, and chest pain are likely to have acute left ventricular failure. This occurs because of increased preload, which is due to the decreased pulmonary capillary compression that occurs when intrathoracic pressure is reduced as a result of being off the ventilator. 21. How long does a tracheostomy site typically take to mature? a. 2–4 days b. 4–6 days c. 7–10 days d. 10–15 days ANS: C
A tracheostomy site typically requires 7–10 days to mature.
22. A patient who requires prolonged ventilatory support should not be considered permanently
ventilator dependent until during that time have failed. a. 1 b. 3 c. 6 d. 9
month(s) has/have passed and all weaning attempts
ANS: B
Unless evidence of irreversible disease exists, a patient who requires prolonged ventilatory support should not be considered permanently ventilator dependent until 3 months have passed and all weaning attempts during that time have failed. 23. A patient being actively weaned from mechanical ventilation currently is receiving the
following ventilatory support: pressure support = 15 cm H2O, spontaneous VT = 575 mL, spontaneous rate = 14 breaths/min, spontaneous VT = 500 mL, FIO2 = 35%, PEEP = 5 cm H2O. The arterial blood gas results are: pH = 7.42, PaCO2 = 38 mm Hg, PaO2 = 94 mm Hg, SaO2 = 98%, HCO3– = 24 mEq/L. What should the respiratory therapist do next? a. Reduce PEEP to zero. b. Reduce the FIO2 to 30%. c. Reduce the PS to 10 cm H2O. d. Extubate the patient. ANS: C
At this point, the ABG results show no acid–base imbalance and no hypoxemia. The parameter that should be reduced is the pressure support. When pressure support is reduced to about 5 cm H2O, the pressure level is not high enough to contribute significantly to ventilatory support. Once at PS 5 cm H2O, the patient will be ready for a cuff leak test. 24. Which of the following would suggest that a patient is ready to be weaned from a ventilator? a. Vital capacity (VC) of 8 mL/kg ideal body weight (IBW) b. PaO2 or 65 mm Hg on and FIO2 of 0.6 c. Dead space-to-tidal volume ratio (VD/VT) of 0.75 d. Rapid shallow breathing index of 75 breaths/min/L ANS: D
The RSBI is the most frequently studied and one of the more reliable tests for determining a patient’s weaning status. It is calculated by dividing the respiratory frequency (in breaths/min) by the VT (in L): f/VT. This measurement is taken 1 minute after disconnecting the spontaneously breathing patient from the ventilator and oxygen. Successful weaning is more likely if the RSBI is less than 105 (normal range, 60–105). Values above 105 suggest that a patient is not ready for weaning and probably will fail a weaning trial. 25. A patient in the ICU who has successfully completed a 120-minute SBT requires extubation.
Which of the following tests or values would indicate the potential for airway edema after extubation? a. PImax b. VC c. Cuff leak test d. Oxygen saturation measured by pulse oximeter (SpO2)
ANS: C
The cuff leak test is a means of testing for post-extubation airway patency. Note that to qualify for this test, the patient must no longer need ventilatory support. To perform this test, the patient is disconnected from the ventilator, the cuff is deflated, and the ET or tracheostomy tube is obstructed. A leak around the cuff (peritubular leak) during spontaneous breathing suggests that the airway caliber is adequate and successful extubation is likely. A leak of less than 110 mL (average of three values on six consecutive breaths) indicates a high risk for post-extubation stridor. Treatment with steroids or racemic epinephrine (or both) before extubation may be indicated. 26. A patient with amyotrophic lateral sclerosis has a tracheostomy tube in place. He has been
unable to perform an SBT successfully and has been receiving mechanical ventilation for 4 months. An appropriate recommendation for this patient might be which of the following? 1. Transfer to a long-term care facility 2. Evaluation for the use of noninvasive ventilation (NIV) 3. Termination of ventilation 4. Waiting until the primary cause of respiratory failure has been resolved a. 1 and 2 only b. 2 and 3 only c. 1, 2, and 3 only d. 1, 2, and 4 only ANS: A
Unless evidence of irreversible disease exists, a patient who requires prolonged ventilatory support should not be considered permanently ventilator dependent until 3 months have passed and all weaning attempts during that time have failed. Those failing to wean may require placement in a long-term care facility. 27. When weaning is unsuccessful for a patient who successfully performs an SBT, which of the
following factors should be assessed? 1. Cardiac factors 2. Nutritional status and respiratory muscle strength 3. Acid–base status 4. Psychological factors a. 1 and 3 only b. 2 and 4 only c. 2, 3, and 4 only d. 1, 2, 3, and 4 ANS: D
Category Factor Mechanism Clinical Presentation Category Factor Mechanism Cardiac status Acute leftIncreased preload ventricular failure because of increased venous return and decreased pulmonary capillary compression as intrathoracic pressure is reduced.
Clinical Presentation Weaning fails, often after patient does well initially for 30–60 minutes; may develop acute respiratory and/or metabolic acidosis, hypoxemia, hypotension, chest pain, and cardiac
Acid–base status
Metabolic status
Drugs
Acute alkalosis in patient with underlying carbon dioxide (CO2) retention
Loss of preexisting metabolic compensation for hypercapnia; inability to sustain required and WOB.
Respiratory alkalosis
Depression of ventilatory drive by hypocapnia and alkalemia.
Metabolic acidosis
Increase in ventilatory demand to compensate for respiratory alkalosis.
Hypophosphatemia and hypomagnesemia
Ventilatory muscle weakness.
Hypothyroidism
Decreased ventilatory drive with possible ventilatory muscle weakness.
Narcotics, sedatives, tranquilizers, and hypnotics
Depression of ventilatory drive.
Neuromuscular blocking agents
Ventilatory muscle weakness; delayed clearance in patient with renal insufficiency.
dysrhythmias. Patient with COPD or other cause of chronic respiratory acidosis before acute insult fails weaning after several days of ventilation to a PaCO2 lower than the patient’s pH-compensated level. PaCO2 rises and pH falls during weaning attempt; patient is said to fail weaning if some arbitrary change in these values (e.g., 10 mm Hg increase in PaCO2) is used as a criterion for failure. Patient may be unable to sustain required increase in and WOB to maintain a lower PaCO2 to compensate for a lower − HCO3 . Patient weaning fails because of rapid shallow breathing, respiratory distress, and acute respiratory acidosis; maximal inspiratory pressure is decreased. Rare cause of weaning failure that occurs because of acute respiratory acidosis with or without respiratory distress. Patient fails weaning because of acute respiratory acidosis in the absence of tachypnea and respiratory distress. Patient weaning fails because of rapid shallow breathing, respiratory distress, and acute respiratory acidosis; maximal inspiratory pressure is reduced.
Aminoglycosides
Nutrition
Psychological status
Ventilatory muscle weakness caused by acute myopathy, especially in patients who have received high-dose systemic corticosteroids. Neuromuscular blockade.
Overfeeding
Increased CO2 production, especially with excessive carbohydrate calories.
Malnutrition
Effects of acute illness; preexisting nutritional deficiencies.
Agitation; “psychological ventilator dependence”
Anxiety, fear, delirium, ICU psychosis, or influence of preexisting personality factors.
Lack of motivation
Depression, effects of drugs, organic brain dysfunction, or influence of preexisting personality factors.
Same as above; may have elevated muscle enzymes; can last for weeks or months.
Very rare cause of weaning failure that occurs because of rapid shallow breathing, respiratory distress, and acute respiratory acidosis; maximal inspiratory force is reduced. Patient fails weaning because of excessive ventilatory demand (high requirement to keep PaCO2 normal); unusual cause of weaning failure unless very large caloric loads are administered. May contribute to ventilatory muscle weakness, decreased ventilatory drive, impaired immunological function, fluid retention, depression; distinguishing this from other factors is difficult. Patient becomes agitated and panicky during attempt to reduce or discontinue ventilatory support; can be said to cause weaning failure when other factors are absent. Patient refuses to participate in care (e.g., mobilization, bronchial hygiene, physiological measurements); flat affect and immobility in bed; considered when other factors are absent.
Chapter 21: Long-Term Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. The American College of Chest Physicians (ACCP) considers long-term ventilator-assisted
patients to be those who require mechanical ventilation for at least days or more. a. 4; 7 b. 6; 14 c. 6; 21 d. 8; 21
hours per day for
ANS: C
The ACCP considers LTV-assisted patients to be those who require mechanical ventilation for at least 6 hours a day for 21 days or longer. 2. One of the goals of long-term mechanical ventilation (LTMV) in the home or alternative care
site is which of the following? a. Permit lung healing b. Reduce hospitalizations c. Relieve respiratory distress d. Improve pulmonary gas exchange ANS: B
The overall goal of LTMV at home or in other alternative care sites is to improve the patient’s quality of life by enhancing the individual’s living potential; improving the patient’s physical and physiological level of function; reducing morbidity; reducing hospitalizations; extending life; and providing cost-effective care. The other options are the goals of acute mechanical ventilation. 3. Which site for mechanical ventilation of patients provides the least patient independence and
quality of life? Intensive care unit Skilled nursing facility Long-term care hospital Chronic-assisted ventilator unit
a. b. c. d.
ANS: A
ICUs and CCUs provide invasive monitoring, extensive care, and a higher ratio of practitioners to patients. Therefore, these units are both more expensive and provide the least patient independence and quality of life. All the other options provide the patient with more independence and, as such, quality of life. 4. The preferred location for ventilator-dependent patients is a. a skilled nursing facility b. a subacute care unit c. their own homes d. a long-term acute care hospital
.
ANS: C
The person’s own home is the preferred location for a ventilator-dependent patient; it is the least expensive option and provides the best quality of life for these individuals. Long-term acute care hospitals are designed to care for patients who require extensive monitoring and care. These patients may still be acutely ill, but they no longer require the intensive care provided in a hospital CCU. A subacute care unit is an intermediate care site, which is not as expensive as an acute care site and provides somewhat more patient independence and quality of life. A skilled nursing facility is considered a long-term care site. These sites do not have the resources to treat acutely ill patients. 5. A patient with which condition is a suitable candidate for homecare ventilation? a. Flail chest due to trauma b. Amyotrophic lateral sclerosis c. Severe exacerbation of asthma d. Acute respiratory distress syndrome ANS: B
A patient with ALS will become completely ventilator dependent and depend on life support from the ventilator. A patient with flail chest due to trauma is acutely ill and usually can be weaned in the intensive care unit. A patient with severe exacerbation of asthma requires ventilation only for a short time, until the exacerbation has resolved. Patients with ARDS require intensive care and usually are not sent home with ventilators. 6. A minimum of
days should be allowed to obtain insurance verification and authorization and to procure equipment before a ventilated patient is transferred home from the acute care hospital. a. 3–5 b. 7–14 c. 10–16 d. 21–30 ANS: B
Before a patient is transferred home with a ventilator, a minimum lead time of 7–14 days is often required so that insurance verification and authorization can be obtained and equipment procured. 7. List the potential locations for patients requiring long-term ventilatory care in order of cost
from most expensive to least expensive. 1. Patient’s home 2. Long-term acute care facility 3. Intensive care or acute care unit 4. Extended care facility a. 2, 4, 3, 1 b. 4, 1, 3, 2 c. 1, 2, 3, 4 d. 3, 2, 4, 1 ANS: D
Mechanical ventilatory care can be provided in ICU or acute care units, long-term acute care facilities, extended care facilities, and the patient’s home. An ICU or acute care unit is the most expensive of the facilities listed, and the patient’s home is the least expensive. 8. In-hospital evaluation of ventilator-assisted infants should be performed how often for the first
2 years of life? Once a month Once every 2–3 months Once every 4–6 months Once a year
a. b. c. d.
ANS: B
For the first 2 years of life, ventilator-assisted infants should be evaluated in the hospital every 2–3 months; the ventilator requirements of infants and children change because of their growth and development. 9. The most important factors to consider when choosing a ventilator for home use include
which of the following? 1. Sophistication 2. Reliability 3. Versatility 4. Cost a. 1, 2, and 4 only b. 2, 3, and 4 only c. 1, 2, and 3 only d. 1 and 2 only ANS: B
The most important factors in choosing a ventilator are: • Reliability. The ventilator must be mechanically dependable and trouble free for extended periods without breaking down or requiring costly maintenance. • Safety. The ventilator must be safe to operate in oxygen-enriched environments and have an adequate alarm system to warn of low ventilating pressure, high ventilating pressure, patient disconnection, and mechanical failure. • Versatility. The ventilator should be portable or adjustable for travel outside the home; it must have reliable internal and external battery sources and alarms. • User friendliness. Ventilator controls should be easy to understand and manipulate. The circuit should be simple and easy to change. • Ease of patient cycling. The ventilator should be easy to cycle in the volumecontrolled continuous mandatory ventilation (VC-CMV) mode for patients with some spontaneous effort. 10. A patient with a tracheostomy tube (TT) is being discharged home with a ventilator, which he
uses only during the night, without supplemental oxygen. During the day he uses a speaking valve. Which of the following equipment must he have in his home? 1. Suctioning equipment 2. Oxygen concentrator 3. Second mechanical ventilator 4. Manual resuscitator bag a. 1 and 3 only
b. 1 and 4 only c. 2, 3, and 4 only d. 2, 3, and 4 only ANS: B
The patient does not use oxygen; therefore, an oxygen concentrator is not necessary. Also, because the patient uses the ventilator only at night, a second ventilator is not necessary. Suctioning equipment and a self-inflating manual resuscitator bag are necessary for any patient with a TT. 11. A quadriplegic patient is getting ready for discharge home from an acute care hospital. He has
a TT and requires mechanical ventilation around-the-clock, but does not need supplemental oxygen. What equipment must he have in his home? 1. Transport ventilator 2. Manual resuscitator bag 3. E-cylinder of oxygen 4. Ventilator circuits a. 1 and 2 only b. 3 and 4 only c. 1, 2, and 4 only d. 2 and 4 only ANS: C
All ventilator-assisted individuals (VAIs) require a self-inflating manual resuscitator. Patients who are totally dependent on a ventilator and use a wheelchair need a transport ventilator for their wheelchair and as a backup ventilator. This patient does not require oxygen; therefore, an oxygen cylinder is not necessary. VAIs should have at least three ventilator circuits in their homes. 12. The appropriate power source for a wheelchair-mounted ventilator is which of the following? a. AC current b. Pneumatic c. Internal DC battery d. External DC battery ANS: D
An external DC battery allows the ventilator to be mounted and used on a wheelchair or in a car. Use of an external DC battery enables longer operation, as needed, during transport. 13. Which of the following factors must be considered when estimating a patient’s cost of home
mechanical ventilation? 1. Type of ventilator selected 2. Accessory medical supplies 3. Need for professional caregivers 4. Adequacy of third-party coverage a. 1 and 3 only b. 2 and 4 only c. 1 and 4 only d. 1, 2, 3, and 4 ANS: D
For homecare patients, ventilator equipment can be bought at a reasonable price; however, in many cases, families may choose to rent the ventilator because regular service, maintenance, and 24-hour emergency services are available as part of the rental contract. Unfortunately, the costs of accessory medical supplies, including items such as suction catheters, skin lotions, and absorbent underpads, may be difficult to estimate and can significantly increase the total cost of care. The major factor affecting the cost of homecare is the need for professional or skilled caregivers. This cost depends on the availability of family members and how much they are willing and able to do. Cost also depends on patient independence and self-care abilities and the number of hours and level of care required from others. It is important to recognize that inadequate third-party coverage for supplies and equipment, which is almost always passed on to the patient and family, must be factored into the costs of providing LTMV in the home. 14. A patient with muscular dystrophy currently receiving ventilatory support with VC-IMV is
being prepared for discharge home. The case manager asks the respiratory therapist to recommend a ventilator that will meet the patient’s needs with the least complexity and at the lowest cost. The respiratory therapist should recommend which of the following ventilators? a. PLV 102 b. LP-6 Plus c. LTV 1200 d. PLV 100 ANS: C
The LTV 1200 is the most appropriate choice, because IMV is incorporated into the ventilator, and the associated WOB is lower than that of the first-generation ventilators (PLV 102, LP-6 Plus, and PLV 100). This is important because this patient has a neuromuscular disease and may not be able to endure an increased WOB. Also, because the first-generation ventilators listed do not have internal IMV capabilities, an external H-valve assembly would have to be attached. This means additional equipment with increased complexity and possibly a higher cost compared with the second-generation ventilator (LTV 1200). 15. Which of the following ventilator requirements for a ventilator-assisted individual
demonstrates clinical stability and indicates that the patient most likely is ready for discharge home from an acute care hospital? a. PC-CMV, f = 14 breaths/min, PIP = 30 cm H2O, PEEP = 10 cm H2O, FIO2 = 0.5 b. VC-IMV, f = 8 breaths/min, VT = 400 mL, PS = 5 cm H2O, PEEP = 5 cm H2O, FIO2 = 0.3 c. VC-CMV, f = 12 breaths/min, VT = 600 mL, PEEP = 8 cm H2O, FIO2 = 0.6 d. PC-IMV, f = 10 breaths/min, PIP = 25 cm H2O, PS = 10 cm H2O, PEEP = 10 cm H2O, FIO2 = 0.8 ANS: B
Because the second-generation homecare ventilators can deliver PC-CMV and VC-CMV or IMV and PSV and PEEP, the fact that these patients require these modes does not exclude them from being considered for home ventilation. Patients are not considered for home ventilation if they require an FIO2 greater than 0.4 and higher levels of PEEP, because this demonstrates clinical instability. 16. What bacteria is most often the cause of ventilator-associated pneumonia in VAIs?
a. b. c. d.
Staphylococcus aureus Enterobacter spp. Burkholderia cepacia Streptococcus pneumoniae
ANS: B
Unlike nosocomial infections in the ICU setting, ventilator-associated pneumonia in VAIs often is caused by enteric gram-negative bacteria, such as Enterobacter spp., Escherichia coli, Klebsiella spp., and Pseudomonas aeruginosa. 17. A patient using a negative pressure ventilator is assessed by the respiratory therapist and
found to have a blood pressure of 85/40 mm Hg and a heart rate of 130 beats/min and thready. The physician orders compression stockings for the patient, but the clinical status is the same 24 hours after placement of the compression stockings. What is the most likely cause of this patient’s hypotension? a. Diarrhea b. Dehydration c. Septicemia d. Abdominal blood pooling ANS: D
Negative pressure ventilators can cause pooling of blood in the abdominal vasculature. This leads to a decrease in venous return to the heart and, subsequently, a reduction in cardiac output. The result is hypotension, especially if the patient is hypovolemic. 18. What pressure range may be necessary to achieve a sufficient VT using a chest cuirass? a. −10 to −20 cm H2O b. −25 to −50 cm H2O c. −35 to −60 cm H2O d. −50 to −75 cm H2O ANS: C
Pressures of −35 to −60 cm H2O may be necessary to achieve a sufficient VT with a chest cuirass. 19. Glossopharyngeal breathing is beneficial for patients with which condition? a. Tracheomalacia b. Postpolio syndrome c. Muscular dystrophy d. Pierre-Robin syndrome ANS: B
Patients who may benefit from learning glossopharyngeal breathing include those with a spinal cord injury or postpolio syndrome. 20. A VAI with amyotrophic lateral sclerosis and a TT is unable to develop clear secretions from
his airway. Which of the following should be considered to manage this patient’s airway clearance problem? 1. Manual chest compression and TT suctioning 2. Autogenic drainage and postural drainage 3. Positive expiratory pressure
4. Mechanical insufflation-exsufflation (MI-E) 1 and 4 only 1, 2, and 3 only 2 and 3 only 1, 2, and 4 only
a. b. c. d.
ANS: A
Because this patient has ALS and is ventilator dependent, removing the patient will not enable the RT to perform PEP therapy or autogenic drainage. Assisted coughing with manual chest compression helps to mobilize secretions into an area in the larger airways that can be suctioned. MI-E also is appropriate for a patient, such as this one, who is unable to generate enough expiratory flow for a cough. 21. What is the minimum pressure required to vibrate the vocal cords and produce a quality
voice? 1 cm H2O 2 cm H2O 3 cm H2O 4 cm H2O
a. b. c. d.
ANS: B
For speech to occur, tracheal pressures of approximately 2 cm H2O are required to vibrate the vocal cords and produce a quality voice. 22. A VAI patient with a TT is having a trial of cuff deflation to allow for speech. The patient’s
voice is “weak,” and he can speak only two or three words with each exhalation. The respiratory therapist could adjust which ventilator settings to improve the patient’s speech? 1. Expiratory time 2. Inspiratory time 3. Volume 4. PEEP a. 1 and 3 only b. 2 and 4 only c. 1 and 4 only d. 2 and 3 only ANS: B
When the cuff is deflated, the ventilator increases flow during exhalation to maintain the setPEEP because a leak is detected. PEEP impedes expiratory flow through the ventilator expiratory valve, so airflows through the larynx. By using a longer inspiratory time and PEEP, the additive effect produces increased speaking time and improved speech quality. 23. A VAI patient has expressed the desire to be able to speak. The most appropriate speaking
device to use inline with this ventilator patient is which of the following? Voice TT Passy-Muir Portex Speaking TT Pitt Talking TT
a. b. c. d.
ANS: B
The Passy-Muir currently is the only valve that the U.S. Food and Drug Administration (FDA) has approved for use inline with a ventilator. 24. Which of the following is an essential step the respiratory therapist must perform when setting
up a speaking valve for a ventilator-assisted individual? Turn up the required flow to 6–8 L/min. Make sure the cuff is inflated before applying the valve. Make sure the cuff is deflated before applying the valve. Place the speaking valve in a 22-mm corrugated tube.
a. b. c. d.
ANS: C
For the speaking valve to work, the cuff of the TT must be deflated. A speaking valve does not require a separate air source. The speaking valve can be placed in a corrugated tube that is attached to the ventilator’s Y-connector. 25. During an education session with the family of a ventilator-assisted individual who is being
prepared for discharge home, the respiratory therapist explains ventilator circuit/suction equipment disinfection. Which of the following is an important instruction that should be part of this teaching? a. “A white vinegar/distilled water mix can be reused as a disinfectant solution.” b. “Water for humidifiers can be taken directly from the tap.” c. “Suction catheters and plastic containers must be changed after 8 hours.” d. “Medicare will reimburse for all the disposable supplies needed for the ventilator.” ANS: C
Suction catheters and the plastic containers must be changed after 8 hours of use. The white vinegar/distilled water mix must be discarded and may not be reused. If tap water is to be used in the humidifier or as a diluent, it must be boiled for 30 minutes and stored in a sterile container in the refrigerator. Medicare does not reimburse for most disposable supplies or reimburses for only a limited number of disposable supplies. 26. Some of the difficulties families experience when caring for a patient in the home include
which of the following? 1. Loss of work time 2. Loss of privacy when outside caregivers are in the home 24 hours a day 3. Financial stress 4. Transmission of nosocomial infections from patient to family a. 1 and 3 only b. 2 and 4 only c. 1, 2, and 3 only d. 1, 2, 3, and 4 ANS: D
In cases where the patient will be going home, a detailed psychological evaluation may be necessary to determine the ability of the patient and family to cope with stress. If the requirements for patient care exceed the family’s capabilities, professional assistance is essential. The availability of other support systems such as home health agencies, respite care, and psychological consultants is often critical to the success or failure of homecare candidates. The need for support and counseling is assessed before discharge and reassessed periodically while the patient remains on mechanical ventilatory support. It is important to recognize that despite the significant savings accrued when a patient receives ventilatory care in the home, the overall cost can strain family budgets, even for those who are insured. 27. Follow-up assessment of a patient who is home ventilated on a regular service schedule
generally includes which of the following? 1. Vital signs 2. Arterial blood gas (ABG) evaluation 3. Oxygen saturation measured by pulse oximeter (SpO2) 4. Portable chest radiograph a. 1 only b. 2 only c. 1 and 3 only d. 2, 3, and 4 only ANS: C
Evaluations during home visits may include patient assessment parameters such as bedside pulmonary function studies, vital signs, and pulse oximetry. Assessment in the home does not generally include ABG studies. 28. A written report should be completed monthly during the follow-up and evaluation of patients
receiving home MV. Which of the following conditions should this monthly report include? 1. ABG analysis 2. Patient and family comprehension of equipment and procedures 3. Proper functioning of the equipment 4. Compliance with the plan of care a. 2, 3, and 4 only b. 1, 2, and 3 only c. 1, 2, and 4 only d. 3 and 4 only ANS: A
A written report is completed after the monthly visit, and copies are sent to the patient’s physician, homecare agency, and other members of the healthcare team. This report might include the following: • Identification of company, servicing location, date, and time • Patient name, address, phone, and e-mail • Patient diagnosis • Physician and phone number • Prescribed equipment and procedures • Assessment (vital signs, breath sounds, sputum evaluation, oxygen saturation (SpO2), ventilator parameter and alarm settings, functioning of ancillary equipment) • Caregiver and patient (if possible) comprehension of equipment and procedures • Compliance with plan of care
•
Recommendations of DME company representative
29. The advantages of using MI-E in conjunction with PPV include:
1. MI-E with PPV generates optimal peak cough expiratory flow (PCEF) for clearing airway secretions. 2. MI-E with PPV does not cause airway irritation or discomfort. 3. MI-E with PPV can be used with patients with bullous emphysema. 4. MI-E with PPV may improve vital capacity (VC) and arterial oxygen saturation (SaO2) associated with mucous plugging. a. 1, 2, and 4 only b. 2, 3, and 4 only c. 2 and 4 only d. 1, 3, and 4 only ANS: A
The MI-E may be the most effective alternative for generating optimal peak cough expiratory flow (PCEF) and clearing airway secretions. PCEF has increased to as much as 6–10 L/s during therapy and can be increased more if a manual abdominal thrust can be synchronized with exsufflation. MI-E does not cause the airway irritation and discomfort associated with tracheal suctioning and may actually decrease the production of airway secretions. Abnormal VC values, flows, and arterial oxygen saturation (SaO2) values can also significantly improve with clearing of mucous plugs by MI-E. No significant complications have been reported with the use of this device. However, it is contraindicated in patients with bullous emphysema or pulmonary disorders that predispose a patient to barotrauma. 30. A patient is experiencing eye irritation with their mask CPAP. Which of the following is a
possible solution? Alter sleeping position Do not use the CPAP Correct mask leaks Use PSV
a. b. c. d.
ANS: C
Problem Possible Solution Problem Aerophagia—gastric distention
Hypoxemia/desaturation Nasal dryness or congestion Eye irritation Patient discomfort from head straps Nasal or dental pain, dental deformities
Possible Solution Lower peak inspiratory pressure (<20–25 cm H2O) Use PSV Alter sleeping position Use abdominal strap Correct mouth leaks Increase CPAP levels Increase humidification Spray nasal passages with saline Correct mask leaks Use other interfaces Alternate other interfaces Alternate other interfaces
Chapter 22: Neonatal and Pediatric Mechanical Ventilation Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. Respiratory failure is imminent in infants who demonstrate which of the following? a. Substernal retractions b. Tachypnea c. Grunting d. Nasal flaring ANS: C
Infants attempt to maintain a back pressure in the lungs to preserve the functional residual capacity by narrowing the glottis and maintaining respiratory muscle activity (active exhalation). This results in vocalization during exhalation, or “grunting,” which is often mistaken for crying. Grunting, which usually can be heard without auscultation, is a useful clinical sign of impending respiratory failure. 2. The primary goals of mechanical ventilatory support in newborns and pediatric patients
include all of the following except improving lung compliance eliminating airway resistance achieving adequate lung volume limiting lung injury
.
a. b. c. d.
ANS: B
The goals of mechanical ventilatory support in newborns and pediatric patients are to (a) provide adequate ventilation and oxygenation, (b) achieve adequate lung volume, (c) improve lung compliance, (d) reduce WOB, and (e) limit lung injury. If airway resistance is a problem, it needs to be addressed; however, eliminating it is not a goal of mechanical ventilatory support. 3. A newborn with which of the following clinical manifestations should receive nasal CPAP? a. Substernal retractions, PaCO2 = 65 mm Hg, PaO2 = 48 mm Hg, FIO2 = 0.4 b. Tachypnea, nasal flaring, PaCO2 = 50 mm Hg, PaO2 = 50 mm Hg, FIO2 = 0.6 c. Grunting, substernal retractions, pH = 7.20, PaCO2 = 70 mm Hg, PaO2 = 40 mm
Hg, FIO2 = 0.7 d. Tachypnea, pale skin, pH = 7.32, PaCO2 = 45 mm Hg, PaO2 = 75 mm Hg, FIO2 = 0.21 ANS: B
A newborn with tachypnea, nasal flaring, a PaCO2 of 50 mm Hg, a PaO2 of 50 mm Hg, and an FIO2 of 0.6 meets the criteria for nasal CPAP. A newborn with these findings not only has adequate minute ventilation, as evidenced by the PaCO2 of 50 mm Hg, but also has hypoxemia that is not being corrected by an FIO2 of 0.6. The newborn in option A (substernal retractions, PaCO2 = 65 mm Hg, PaO2 = 48 mm Hg, FIO2 = 0.4) does not have an adequate minute ventilation and requires some ventilatory assistance. Mechanical ventilation is indicated for the newborn in option C (grunting, substernal retractions, pH = 7.20, PaCO2 = 70 mm Hg, PaO2 = 40 mm Hg, FIO2 = 0.7), because this patient has respiratory acidosis and uncorrected hypoxemia. The newborn in option D (tachypnea, pale skin, pH = 7.32, PaCO2 = 45 mm Hg, PaO2 = 75 mm Hg, FIO2 = 0.21) has two of the physical indications for CPAP, but the ABG findings demonstrate adequate oxygenation. 4. Infants with which of the following problems would benefit from nasal CPAP? a. Cleft palate b. Choanal atresia c. Patent ductus arteriosus d. Tracheoesophageal fistula ANS: C
A newborn with a patent ductus arteriosus has increased pulmonary blood flow and reduced lung compliance and FRC and therefore would benefit from the positive intrathoracic pressure produced by CPAP. The use of CPAP can be dangerous in newborns with choanal atresia, a tracheoesophageal fistula, or a cleft palate. 5. The most common interface for infants receiving CPAP is which of the following? a. Nasopharyngeal tube b. Binasal prongs c. Nasal mask d. Endotracheal tube ANS: B
The short binasal prongs are the most commonly used interface for infants receiving nasal CPAP. Nasal masks are slowly becoming more popular. The least popular method of administering CPAP is through nasopharyngeal or endotracheal tubes, because they are invasive. 6. Nasal CPAP should be administered to a neonate with a. cleft palate b. choanal atresia c. apnea of prematurity d. tracheoesophageal fistula
.
ANS: C
The use of CPAP can be dangerous in a newborn with choanal atresia, a tracheoesophageal fistula, or a cleft palate. CPAP can be used successfully in infants with apnea of prematurity. 7. The gas flow rate for a noncommercial bubble CPAP device should be set at a. 3 b. 5 c. 8 d. 10
L/min.
ANS: B
Gas flow in noncommercial bubble CPAP devices should be set at 5 L/min. 8. A full-term neonate shows signs of respiratory distress after delivery by cesarean section. The
baby is placed on nasal CPAP at 4 cm H2O with an FIO2 of 0.6. The ABG results on these settings are: pH = 7.32, PaCO2 = 45 mm Hg, PaO2 = 48 mm Hg, SaO2 = 70%, HCO3– = 22 mEq/L. The respiratory therapist should recommend which of the following? a. Intubate and mechanically ventilate. b. Increase the FIO2 to 0.7. c. Increase the CPAP to 6 cm H2O. d. Intubate and use ventilator CPAP. ANS: C
The ABG results show that the neonate is adequately ventilated. This eliminates the need for NIPPV because the CPAP level is not optimized at this time, and the FIO2 is set at a high level. The ABG results also show that the patient has not had an adequate response to the CPAP of 4 cm H2O with an FIO2 0.6. The CPAP can be increased in increments of 1–2 cm H2O until it reaches 10 cm H2O. Intubating for the use of ventilator CPAP would not provide any benefit over noninvasive CPAP and would increase the risk for nosocomial infection. 9. Bubble CPAP should a. bubble only on expiration b. bubble only on inspiration c. bubble on inspiration and expiration d. have a gas flow setting of 10 L/min
.
ANS: C
Bubble CPAP should have the lowest possible flow to maintain constant bubbling throughout the respiratory cycle. 10. NIV can be used successfully in neonates for which of the following? a. Severe ventilatory impairment b. Persistent apnea c. After extubation d. Cleft palate ANS: C
NIV can be used as an initial form of respiratory support and also after extubation from invasive mechanical ventilation. 11. A neonate of 30 weeks’ gestation shows signs of respiratory distress after delivery, including
grunting, nasal flaring, and cyanosis. The baby is placed on nasal CPAP at 6 cm H2O with an FIO2 of 0.6. The grunting and nasal flaring are alleviated, and the ABG results on these settings are: pH = 7.20, PaCO2 = 64 mm Hg, PaO2 = 48 mm Hg, SaO2 = 70%, HCO3– = 21 mEq/L. The respiratory therapist should recommend which of the following? a. Increase the CPAP to 8 cm H2O and the FIO2 to 0.7. b. Switch to nasal IMV, an inspiratory pressure of 18 cm H2O, PEEP of 4 cm H2O, and an FIO2 of 0.8. c. Continue with the current settings and monitor the patient closely. d. Intubate and use PC-IMV, an inspiratory pressure of 16 cm H2O, PEEP of 5 cm
H2O, and an FIO2 of 0.8. ANS: D
This neonate meets the requirements for invasive mechanical ventilation because of continued signs of respiratory distress: respiratory acidosis and a PaO2 of 48 mm Hg with an FIO2 of 0.6. Remaining in CPAP would not address the respiratory acidosis or the hypoxemia. Increasing the CPAP level and the FIO2 would not address the respiratory acidosis. This patient is showing severe ventilatory impairment (pH <7.25, PaCO2 >6 mm Hg) and refractory hypoxemia (PaO2 <50 mm Hg on an FIO2 >0.6); therefore, the patient should not be placed on NIPPV. 12. Potential harmful effects of nasal CPAP include which of the following? a. Volutrauma b. CO2 retention c. Oxygen toxicity d. Ventilator-induced lung injury ANS: B
CPAP can cause pulmonary overdistention, which can increase WOB and cause CO2 retention. Volutrauma and VILI are associated with invasive mechanical ventilation. Oxygen toxicity is related to the PaO2 that results from FIO2 levels higher than 0.6. 13. A newborn of 32 weeks’ gestation is currently receiving nasal CPAP. The respiratory therapist
recently increased the CPAP level from 8 to 10 cm H2O; the FIO2 is 0.6. On the new setting, the PaO2 is 52 mm Hg and the PaCO2 increased from 48 to 55 mm Hg. The most likely cause of this is which of the following? a. Barotrauma b. Alveolar overdistention c. Ventilator-induced lung injury d. Increased pulmonary vascular resistance ANS: B
The rise in CO2 after the increase in the CPAP level is most likely due to pulmonary overdistention, which leads to increased work of breathing. The increased WOB causes CO2 retention. 14. The pressure manometer inline with a bubble CPAP setup is reading higher than the depth of
the expiratory limb in the liquid-filled bottle. This is most likely caused by which of the following? a. Set flow rate above 5 L/min b. Set flow rate below 5 L/min c. Fluid in the inspiratory line d. Improperly placed manometer ANS: A
The set flow rate for a bubble CPAP setup is 5 L/min. Flow rates above 5 L/min result in higher pressures than those anticipated by the submersion depth of the distal tubing. Flow rates lower than 5 L/min would not be able to maintain the bubble CPAP level needed for a given depth. Improper placement of the manometer could result in lower pressures than expected, because the manometer would not be reading pressure on exhalation. Fluid in the inspiratory line may drop the pressure reading by the manometer, because it would cause back pressure behind the fluid. 15. Which of the following are contraindications for the use of pressure support in neonates
receiving nasal IMV? 1. Large airway leaks 2. Ineffectiveness of triggering 3. Increased risk for volutrauma 4. Hypocapnia from excessive triggering a. 1 and 2 only b. 1 and 3 only c. 2 and 3 only d. 2 and 4 only ANS: A
Pressure support is typically not provided to assist spontaneous breaths during nasal IMV because of large airway leaks and ineffective triggering. 16. Neonatal patients are more vulnerable to rapid deterioration because of a. high chest wall compliance b. low functional residual capacity c. smaller surface area for gas exchange d. presence of fetal hemoglobin
.
ANS: C
Neonatal and pediatric patients have smaller lungs, higher airway resistance, lower lung compliance, less surface area for gas exchange, and lower cardiovascular reserve than do adults; all of these factors make them more vulnerable to rapid deterioration. Although neonates have high chest wall compliance, this is not the reason for their vulnerability to rapid deterioration. It is the reason for the presence of retractions when the WOB is elevated. 17. Oxygen delivery and tissue perfusion may be evaluated clinically by which of the following? a. Mucous membrane color b. Skin color and tone c. Capillary refill d. Chest X-ray ANS: C
Oxygen delivery and tissue perfusion can be evaluated clinically by noting the capillary refill. 18. The minimum acceptable pH for a premature or term newborn is which of the following? a. 7.20 b. 7.25 c. 7.30 d. 7.35
ANS: B
The minimum acceptable pH for a premature or term newborn is 7.25. Values below that level are considered inadequate, especially when the PaCO2 is greater than 50 mm Hg. 19. The mode of ventilation that allows a neonate to breathe at a high and a low CPAP setting is
which of the following? SiPAP HFOV Nasal IMV Nasal HFV
a. b. c. d.
ANS: A
Nasal SiPAP allows the neonate to breathe continuously at CPAP and during a sustained “sigh” breath to recruit lung units at two different lung volumes. It allows the neonate to breathe at a high and a low CPAP setting. 20. A 5-year-old patient diagnosed with tracheomalacia after a long intubation has had numerous
failures to wean and extubate. What should the respiratory therapist recommend to help alleviate spontaneous breathing problems associated with tracheomalacia until a stent can be placed in the airway? a. BiPAP b. Nasal HFV c. Nasal SiPAP d. Tracheostomy and CPAP ANS: D
Tracheomalacia can make weaning from ventilation and extubation difficult. A tracheotomy and CPAP would be appropriate for this patient (24 hours a day) until surgery to place a stent in the airway can be performed. 21. A preterm neonate is being supported with nasal SiPAP. The baseline CPAP level is set at 6 cm
H2O, the high CPAP level at 10 cm H2O, the rate is 20 “sigh” breaths, and the FIO2 is 0.8. The baby’s PaO2 on these settings has been steadily declining and is now 48 mm Hg. The physician and respiratory therapist decided to use nasal HFV before intubating and using mechanical ventilation. The initial settings for NHFV for this patient should include which of the following? a. MAP = 10 cm H2O; frequency = 8 Hz; FIO2 = 1.0 b. MAP = 10 cm H2O; frequency = 10 Hz; FIO2 = 0.8 c. MAP = 6 cm H2O; frequency = 8 Hz; FIO2 = 0.8 d. MAP = 6 cm H2O; frequency = 10 Hz; FIO2 = 1.0 ANS: D
The initial mean airway pressure for nasal HFV is usually set to equal the previous level of CPAP, with a frequency of 10 Hz. Because the nasal SiPAP baseline level was set at 6 cm H2O, the NHFV should be set at that level. The only option with those two set parameters includes the FIO2 of 1.0, which should be titrated down when oxygenation improves. 22. Newer ventilators allow neonates to use what type of trigger for better synchronization with
the ventilator? a. Time b. Flow
c. Pressure d. Volume ANS: B
Patients can trigger breaths based on a pressure or flow change that is sensed by the ventilator. In neonates, flow sensing is more sensitive and allows better synchronization than pressure triggering. 23. A 3-month-old, 6.4-kg infant with ARDS is receiving ventilatory support. The initial settings
are: PC-CMV, PIP = 22 cm H2O, PEEP = 5 cm H2O, rate = 30 breaths/min, FIO2 = 0.6. The ABG results show a PaO2 of 48 mm Hg. The respiratory therapist increases the PEEP to 8 cm H2O. The pressure–volume loops below show the change that occurs after this increase. (Loop A [solid line] was generated from the initial settings. Loop B [dashed line] was generated from the increase in PEEP.) The respiratory therapist’s most appropriate action is which of the following? a. Decrease the PEEP to 5 cm H2O. b. Keep the PEEP at 8 cm H2O. c. Decrease the PIP to 20 cm H2O. d. Increase the PIP to 24 cm H2O. ANS: B
The increase in PEEP to 8 cm H2O has led to an immediate rise in volume for the set pressure. According to the infant’s weight, the volume should be 32 mL. The increase in PEEP has brought the volume to that level without overdistention; this means that the PEEP of 8 cm H2O is appropriate and should be maintained. Obtaining an ABG reading at this point would be appropriate. 24. Which type of trigger allows for better synchronization during neonatal ventilation? a. Flow b. Time c. Volume d. Pressure ANS: A
According to the literature, in neonates, flow sensing is more sensitive and shows better synchronization than does pressure triggering. Patient triggering allows for better synchronization than does machine triggering. 25. The number of time constants for almost complete equilibration of alveolar pressure in a
normal infant’s lungs is 1–3 2–4 3–5 4–7
.
a. b. c. d.
ANS: C
Nearly complete equilibrium of alveolar pressures occurs in 3–5 time constants in infant lungs with normal mechanics. 26. The inspiratory time setting for an infant with RDS, airway resistance of 30 cm H2O/(L/s), and
lung compliance of 0.002 L/cm H2O should be which of the following?
a. b. c. d.
0.25 s 0.30 s 0.45 s 0.55 s
ANS: B
Raw CL = 1 time constant. This is 0.06 s in this problem. One time constant multiplied by 5, or 0.30 s, should be the inspiratory time setting for this patient. 27. The inspiratory time setting for an infant with bronchopulmonary dysplasia (BPD), airway
resistance of 45 cm H2O/(L/s), and lung compliance of 0.004 L/cm H2O should be which of the following? a. 0.25 s b. 0.45 s c. 0.6 s d. 0.9 s ANS: D
Raw CL = 1 time constant. This is 0.18 s in this problem. One time constant multiplied by 5, or 0.90 s, should be the inspiratory time setting for this patient. 28. The maximum percent leak that may be allowed around a cuffless endotracheal tube is which
of the following? 6% 12% 19% 25%
a. b. c. d.
ANS: C
Most clinicians consider small leaks (<20%) acceptable and even desirable as an added safety pressure-release site and as assurance that no significant inflammation is present around the tube. 29. A pediatric patient intubated with a 3.5-mm endotracheal tube is receiving pressure support
ventilation. The respiratory therapist notes patient-ventilator asynchrony and a rapid deceleration of flow that prematurely ends inspiration. The most appropriate action to alleviate this is which of the following? a. Increase the PS level. b. Increase the rise time. c. Decrease the PS level. d. Increase the flow cycle. ANS: B
ET tubes smaller than 4.5 mm may provide excessive resistance during PS. This can cause pressurization of the ventilator circuit before sufficient flow enters the patient’s airway. The result is a rapid deceleration of flow, which may prematurely end the inspiratory phase (premature pressure support termination [PPST]). This phenomenon does not allow the augmentation of VT, and patient-ventilator asynchrony may result. When PPST is suspected, a slower rise time can be used, which may reduce or eliminate the problem.
30. A mechanically ventilated pediatric patient in the process of being weaned is switched to PC-
IMV with PS. The respiratory therapist notes that every PS breath is being time cycled. The most likely cause of this is which of the following? a. The PS setting is too high. b. The flow cycle setting is too low. c. This is the normal cycle for PS. d. A large leak is present around the cuffless ET tube. ANS: D
Failure to flow cycle can be due to leaks around the ET or tracheostomy tube. Time cycling is a backup for flow cycling. 31. Neurally adjusted ventilatory assist (NAVA) is particularly useful with newborns because it a. b. c. d.
. reduces gas trapping is not affected by leaks decreases the development of VILA is sensitive to changes in respiratory drive
ANS: B
NAVA is not affected by leaks, because this ventilator trigger uses the electrical activity of the diaphragm. 32. The patient with which of the following conditions should be considered for HFV? a. Status asthmaticus b. Bronchopleural fistula c. Meconium aspiration d. Cystic fibrosis ANS: B
HFV should be considered for a patient with a bronchopleural fistula. 33. Both inspiration and expiration are active in which type of high-frequency ventilation? a. High-frequency positive pressure ventilation b. High-frequency oscillatory ventilation c. High-frequency jet ventilation d. High-frequency percussive ventilation ANS: B
HFOV differs from other types of high-frequency ventilation in several ways; for example, both inspiration and expiration are active in HFOV. 34. During HFOV, oxygenation can be improved by making which of the following changes?
1. Increasing the FIO2 2. Decreasing the amplitude 3. Increasing the MAP 4. Increasing the frequency a. 1 and 2 b. 1 and 3 c. 2 and 3 d. 2 and 4
ANS: B
The MAP and FIO2 controls are used to control the patient’s oxygenation. The amplitude and frequency are used to control the patient’s ventilatory status. 35. An 835-g newborn is receiving HFOV with the following settings: MAP = 10 cm H2O; FIO2 =
0.6; frequency = 10 Hz; amplitude (P) = 20 cm H2O. The ABG values are: pH = 7.35, PaCO2 = 40 mm Hg, PaO2 = 40 mm Hg. Based on these data, which of the following is the most appropriate action? a. Increase the frequency. b. Increase the MAP. c. Decrease the amplitude. d. Decrease the bias flow. ANS: B
Increasing the MAP will improve the patient’s oxygenation status. Oxygenation also can be altered by changing the FIO2. 36. A pediatric patient with air leak syndrome is being ventilated with PC-CMV. The settings are:
rate = 20 breaths/min, TI = 0.8 s, PIP = 30 cm H2O, PEEP = 8 cm H2O, FIO2 = 0.8, MAP = 14 cm H2O. The patient is to be switched to HFOV. What MAP range is appropriate for this patient? a. 8–10 cm H2O b. 10–12 cm H2O c. 12–14 cm H2O d. 14–16 cm H2O ANS: D
The initial MAP usually is set at the same level as or 2–3 cm H2O higher than that required for conventional ventilation. 37. A pediatric patient with a 5-mm ET tube is ready to be switched to PSV. What minimum PS
level should be used for this patient? 4 cm H2O 6 cm H2O 8 cm H2O 10 cm H2O
a. b. c. d.
ANS: B
The minimum PS setting for a patient with a 5-mm ET tube is 6 cm H2O. 38. A neonate is being ventilated with PRVC. The respiratory therapist responds to a low volume
alarm. After checking the patient and the ventilator, the respiratory therapist finds no disconnects. The most appropriate action is which of the following? a. Draw a sample for arterial blood gas evaluation. b. Increase the target volume. c. Put the patient in the PC-CMV mode. d. Recommend surfactant replacement therapy. ANS: B
In the PRVC mode, if the ET tube has a leak, the level of support will be reduced; this occurs because the ventilator is sensing more volume is being delivered for a given pressure, when actually the gas is escaping around the cuffless ET tube. With the alarms set properly, this problem is caught. The patient should be switched to the PC-CMV mode, in which the set pressure is not automatically altered by the ET tube leak. 39. The pressure manometer should be placed at which point in the following CPAP system?
a. b. c. d.
Point A Point B Point C Point D
ANS: C
The manometer belongs near the nasal prongs on the expiratory side of the circuit. 40. Which of the following is the term used to describe the exchange of gas between lung units
with different time constants? Streaming Pendelluft Taylor-type dispersion Diffusion
a. b. c. d.
ANS: B
Pendelluft, which is the exchange of gas between lung units with different time constants, is observed through photographic studies or by the measurement of different pressure values in the airways. Streaming, or asymmetric velocity profiles, is thought to occur because the velocity of gas flow is higher in the center of the airway. Taylor-type dispersion is the enhanced diffusion of gases caused by the turbulence of high gas flows reaching small airways. With this type of enhanced gas transport, simple molecular diffusion likely is enhanced as well because more mixing of inspired and expired gas occurs at more distal points in the tracheobronchial tree.
Chapter 23: Special Techniques Used in Ventilatory Support Cairo: Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications, 7th Edition MULTIPLE CHOICE 1. In the APRV mode, which of the following is considered baseline? a. Plow b. Phigh c. Tlow d. Thigh ANS: B
In the APRV mode, the Phigh is considered the baseline pressure. 2. Compared with pressure-controlled inverse ratio ventilation, APRV does which of the
following? Decreases the cardiac index Reduces the need for sedation Increases the peak airway pressure Increases the central venous pressure
a. b. c. d.
ANS: B
Compared with pressure-controlled inverse ratio ventilation, APRV reduces peak and mean airway pressures, increases cardiac index, decreases central venous pressure, increases urine output, increases oxygen delivery, and reduces the need for sedation and paralysis. 3. The advantage of APRV over VC-CMV or PC-CMV is which of the following? a. It enhances CO2 elimination. b. Volume delivery is consistent. c. Independent lung regions are better ventilated. d. It reduces the risk for ventilator-induced lung injury. ANS: D
APRV can reduce airway pressure in patients with ALI/ARDS; it therefore is also thought to reduce the risk for ventilator-induced lung injury. In APRV, the volume delivery varies, depending on lung compliance, airway resistance, and the patient’s spontaneous effort. APRV helps ventilate the dependent regions of the lungs, which are better perfused, improving the patient’s ventilation/perfusion matching. CO2 elimination is not completely supported by APRV and relies more on the patient’s spontaneous breathing. 4. When Thigh is set at 5.5 s, and the Tlow is set at 0.5 s, what is the set ventilator rate? a. 8 b. 10 c. 14 d. 16 ANS: B
5. Which variable in APRV is responsible for the removal of CO2 from the body? a. Tlow b. Thigh c. Plow d. Phigh ANS: A
During the release time, or Tlow, the patient exhales a volume of gas; this allows ventilation and the removal of CO2 from the body. 6. The variable that allows for an unimpeded expiratory gas flow is which of the following? a. Tlow b. Thigh c. Plow d. Phigh ANS: C
Some practitioners recommend initially setting Plow at 0 cm H2O; this setting allows an unimpeded expiratory gas flow and a rapid drop in pressure. 7. What is the maximum pressure setting for Phigh? a. 25 cm H2O b. 30 cm H2O c. 35 cm H2O d. 40 cm H2O ANS: C
Phigh should not exceed 35 cm H2O, to prevent overdistention injury to the lungs. 8. A patient being ventilated with APRV has the following settings: Phigh = 24 cm H2O; Thigh = 5 s;
Plow = 4 cm H2O; Tlow = 1 s, FIO2 = 0.3. The patient’s spontaneous respiratory rate is 10 breaths/min. The current arterial blood gas values are: PaO2 = 91 mm Hg; PaCO2 = 62 mm Hg. What should the respiratory therapist recommend for this patient? a. Increase the Plow to 5.5 cm H2O. b. Decrease the Tlow to 0.5 s. c. Increase the Phigh to 40 cm H2O. d. Decrease the Plow to 0 cm H2O. ANS: D
To decrease the PaCO2, the Phigh/Plow gradient needs to be increased without increasing the Phigh above 35 cm H2O. Decreasing the Plow to 0 cm H2O is one way to increase that gradient. Increasing the Plow would decrease the gradient and therefore the VT. Although raising the Phigh would increase the pressure gradient and therefore the VT, pressures above 35 cm H2O increase the risk of overdistention injury. 9. A patient with ALI is being ventilated using APRV with the following settings: Phigh = 30 cm
H2O; Plow = 2 cm H2O; Thigh = 6 s; Tlow = 0.8 s; FIO2 = 0.4. The patient’s spontaneous rate is 12 breaths/min. The current ABG values are: PaO2 = 61 mm Hg; PaCO2 = 43 mm Hg. What change should the respiratory therapist recommend for this patient? a. Decrease the Phigh to 25 mm Hg. b. Increase the Thigh to 8 s.
c. Decrease the Tlow to 0.5 s. d. Increase the Plow to 5 cm H2O. ANS: B
To improve oxygenation during the use of APRV, the Phigh establishes the mPaw, which maintains oxygenation by restoring the functional residual capacity. Decreasing the Phigh would derecruit some alveoli and may create a more difficult situation. Increasing the Thigh may be done in 0.5- to 2-s intervals until the oxygenation target is achieved. The Tlow aids the removal of CO2 and helps determine tidal volume. 10. Weaning from APRV includes which of the following? a. Increasing the Phigh and decreasing the Thigh b. Decreasing the Phigh and increasing the Thigh c. Increasing the Plow and decreasing the Tlow d. Decreasing the Plow and increasing the Tlow ANS: B
Weaning from APRV requires “drop and stretch.” This means decreasing the Phigh and increasing the time at that pressure level by 2–3 cm H2O. 11. Which of the following is an alternative method of respiratory support for patients with
ARDS? IPV ILV HFOV Heliox therapy
a. b. c. d.
ANS: C
HFOV can be used to improve oxygenation in patients with ARDS and at the same time can reduce the risk for ventilator-induced lung injury. 12. An adult patient with ARDS is being ventilated with VC-CMV. The settings are: f = 14
breaths/min; VT = 375 mL; PEEP = 16 cm H2O; and FIO2 = 0.8. The patient’s ABG values are: pH = 7.40; PaCO2 = 56 mm Hg; PaO2 = 48 mm Hg; and SaO2 = 83%; the mean airway pressure is 18 cm H2O. The patient’s physician decides on a trial of HFOV. What initial ventilator settings should be used? a. Bias flow = 30 L/min; mPaw = 23 cm H2O; set power to obtain P = 76 cm H2O; f = 6 Hz; TI = 33%; FIO2 = 1.0 b. Bias flow = 35 L/min; mPaw = 76 cm H2O; set power to obtain P = 33 cm H2O; f = 10 Hz; TI = 50%; FIO2 = 1.0 c. Bias flow = 20 L/min; mPaw = 18 cm H2O; set power to obtain P = 76 cm H2O; f = 8 Hz; TI = 33%; FIO2 = 1.0 d. Bias flow = 30 L/min; mPaw = 30 cm H2O; set power to obtain P = 56 cm H2O; f = 6 Hz; TI = 50%; FIO2 = 1.0 ANS: A
The initial settings should be as follows: (1) the initial bias flow for an adult is 25–40 L/min; (2) the mPaw is set at 3–5 cm H2O above the observed during conventional ventilation (typically starting between 25 and 30 cm H2O); (3) the power is set to result in an amplitude 20 greater than the PaCO2 before HFOV; (4) the initial frequency for an adult is 5–6 Hz; (5) the initial inspiratory time percent is 33% or 50% to improve CO2 removal.
13. The HFOV setting that directly affects PaO2 is the a. power b. mPaw c. amplitude d. bias flow
.
ANS: B
The mPaw directly affects the PaO2 by changing the lung volume. 14. The chest radiograph of a patient just placed on HFOV shows the diaphragm at the level of
the seventh rib. Which of the following parameters should be adjusted? mPaw Power Bias flow Amplitude
a. b. c. d.
ANS: A
The mPaw directly affects the PaO2 by changing the lung volume. The position of the diaphragm on the chest radiograph correlates with lung expansion. Adequate lung expansion in an adult shows the ninth posterior rib above the level of the diaphragm in the midclavicular line. With this patient, the diaphragm is only at the seventh rib. Therefore, the mPaw needs to be increased to improve lung expansion. 15. The PaCO2 can be reduced during HFOV by doing which of the following? a. Decreasing the amplitude b. Increasing the frequency c. Increasing the TI% d. Decreasing the cuff leak ANS: C
The PaCO2 can be reduced during HFOV by increasing the amplitude, decreasing the frequency, increasing the TI% to 50%, and increasing the cuff leak. 16. Observation of chest wall movement, or the “chest wiggle factor,” is used to assess the
appropriateness of the mPaw frequency bias flow power setting
.
a. b. c. d.
ANS: D
The appropriateness of the power setting is determined by observing chest wall movement, or the “chest wiggle factor” (CWF). Increased amplitude is also associated with increased chest wall movement. The CWF should be visible from the level of the clavicle to the midthigh. Assessment of chest wiggle is difficult in obese patients. 17. The key property of helium that makes it useful as a therapeutic gas is its a. low cost b. low density c. low solubility
.
d. abundance in nature ANS: B
Helium’s primary use is based on its low density. 18. The most common concentration of heliox is a. 50% helium:50% oxygen b. 60% helium:40% oxygen c. 70% helium:30% oxygen d. 80% helium:20% oxygen
.
ANS: D
The most commonly used concentration of heliox is 80:20 (80% helium and 20% oxygen). This mixture provides the greatest amount of helium, and therefore the lowest density gas, without providing subambient levels of oxygen. Concentrations as low as 50% have been used effectively in patients with large airway obstructions. 19. An 80% He:20% O2 mixture is being delivered to an asthmatic patient by a nonrebreather
mask through an oxygen flowmeter set at 8 L/min. What is the actual flow delivered to the patient? a. 10 L/min b. 12 L/min c. 14 L/min d. 18 L/min ANS: C
The conversion factor for an 80:20 heliox mixture is 1.8. 8 1.8 = 14.4 L/min. 20. Which of the following ventilators tidal volume delivery is least effected by the use of 80:20
heliox? Dräger Dura-2 CareFusion AVEA Servo-i Puritan Bennett 840
a. b. c. d.
ANS: B
Box 23-8 21. The NAVA mode can be used in which of the following situations? a. Paralysis b. Heavy sedation c. Injury to the respiratory brain centers d. Spontaneous breathing ANS: D
The motivation for the development of neurally adjusted ventilatory assist (NAVA) was to allow the spontaneously breathing patient to have greater control of his or her tidal volume, TI and flow. 22. NAVA is available on which of the following ventilators? a. Dräger Dura-2 b. CareFusion AVEA
c. Servo-i d. Puritan Bennett 840 ANS: C
NAVA is a mode of ventilation on the Servo-i ventilator.