Special Edition 2014

SPECIAL EDITION

Supplement to Anesthesiology Newss • AnesthesiologyNews.com • 2014-2015

10th Annual Compendium of Clinical Reviews Cost Accounting In the Operating Room: Assessing Value

Perioperative Fluids: An Evidence-Based Review

Current Concepts In the Management Of the Difficult Airway

Perioperative Management of Patients With Coronary Stents: Considerations for the Anesthesiologist

Current Concepts In the Understanding of Malignant Hyperthermia

Practical Considerations in Urine Drug Screening: Compliance and Regulations for Office-Based Testing

Nerve Monitors and Peripheral Blockade: Assuring Optimal Needle Placement

Ultrasound-Guided Cervical Nerve Root Injections: Safety and Outcomes

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Dear Reader,

W

elcome to the 10th issue of Anesthesiology News Special Edition. This annual reference guide consists of comprehensive reviews written by leading experts in their respective fields.

The Special Edition is intended to supplement the news coverage that you are accustomed to seeing every month in the pages of Anesthesiology News, and online at AnesthesiologyNews.com. Each article addresses a subject that is a core concern for anesthesiologists and anesthesia providers—usually clinical in topic, although this time we have included one review that looks at cost considerations in the operating room.

Reviews that you may have read in Anesthesiology News earlier in the year have been updated for this issue.

Please refer to these reviews throughout the coming year, share them with your colleagues, and look for the next Special Edition in October 2015.

We would greatly appreciate your feedback on this supplement to Anesthesiology News, as well as suggestions. Contact us at anedit@mcmahonmed.com.

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Table of Contents 9

Nerve Monitors and Peripheral Blockade: Assuring Optimal Needle Placement Malikah Latmore, MD D. Matt Levine, MBChB Jeff Gadsden, MD, FRCPC, FANZCA

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Current Concepts in the Understanding Of Malignant Hyperthermia Tae W. Kim, MD Henry Rosenberg, MD Nina Nami, MD

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Perioperative Management of Patients With Coronary Stents: Considerations For the Anesthesiologist Priya A. Kumar, MD

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Perioperative Fluids: An Evidence-Based Review

38

Practical Considerations in Urine Drug Screening: Compliance and Regulations For Office-Based Testing

Elizabeth A. M. Frost, MD

Jeff Gudin, MD

45

Current Concepts In the Management Of the Difficult Airway Carin A. Hagberg, MD

75

Cost Accounting in the Operating Room: Assessing Value Kristen Telischak, MD, CPA

79

Ultrasound-Guided Cervical Nerve Root Injections: Safety and Outcomes Samer Narouze, MD, PhD, FIPP

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A N E ST H E S I O LO GY N E WS .CO M

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MALIKAH LATMORE, MD

D. MATT LEVINE, MBCHB

Regional Anesthesia Fellow St. Luke’s-Roosevelt Hospital Center New York, New York

Regional Anesthesia Fellow St. Luke’s-Roosevelt Hospital Center New York, New York

T

JEFF GADSDEN, MD, FRCPC, FANZCA Associate Professor of Anesthesiology Duke University Medical Center Durham, North Carolina

raditionally, the goal of peripheral

the needle are potentially hazardous

nerve blockade (PNB) has been

and can lead to histologic and clinical

to deposit local anesthetic as

nerve injury.1-4 This recognition has

close as possible to the nerve to ensure

resulted in a paradigm shift during

a successful block. It was once widely

needle placement from “as close as

taught that needle–nerve contact was

possible” to “close enough, but not too

necessary for a reliable block (eg, “no

close.”5 This article reviews the monitors

paresthesia, no anesthesia”). However,

that are currently available to provide

it has become apparent that needle

information about the relationship

puncture, intraneural injection, and

between the needle and the nerve

even simple contact of the nerve with

during nerve block procedures.

Dr. Gadsden has consulted for B.Braun Medical Inc. and received honoraria from Cadence Pharmaceuticals.

Drs. Latmore and Levine report no relevant financial conflicts of interest.

A N E ST H E S I O LO GY N E WS S P E C I A L E D I T I O N • O C TO B E R 2 0 1 4

9

Nerve Stimulation

Injection Pressure

Electrical stimulation has been used for decades as a method for localizing nerves during PNB. Several clinical and animal studies have demonstrated that the distance from the nerve and the intensity of motor response are poorly correlated. That is, a needle tip can be placed intraneurally yet provoke no motor response.6-8 However, data consistently show that the presence of a motor response at a very low current (such as <0.2 mA) during PNB is highly specific for needle-nerve contact or intraneural needle placement and is associated with histologic injury.9-12 In other words, the absence of a motor response is not necessarily reassuring, but if a response is obtained at less than 0.2 mA, the needle likely is either intraneural or engaged in the epineurium and should be withdrawn (Figure 1). As such, we believe the value of nerve stimulation lies less in localization and more in ensuring the absence of a motor response during PNB.

Opening pressure (OP) is the pressure in the needle–tubing–syringe system immediately before the initiation of flow. It is independent of the dimensions of the syringe or needle, and is equal from the needle tip to the plunger. Once flow begins, however, pressure at the needle tip will vary based on factors including syringe/ needle length and diameter, and compliance of the tubing. An OP greater than 20 psi during the injection of local anesthetic has been associated with intrafascicular injection and neurologic injury.2 Moreover, an inability to generate flow with a pressure of less than 15 psi was 97% sensitive for needle–nerve contact in a study of PNBs.4 As such, it is recommended that high-pressure injection be avoided.

Assessing OP by “hand feel” is both subjective and unreliable.15 Two objective methods for measuring injection pressure are the “compressed air injection technique” and commercially available in-line pressure manometers (BSmart, B.Braun Medical; Figures 5-7).16 Injection pressure monitoring is sensitive for detecting contact between the needle and nerve, and for intrafascicular placement of the needle tip. Yet it lacks specificity, as there are many other causes of high injection pressure, such as a blocked needle.

Ultrasound The introduction of ultrasound revolutionized the practice of regional anesthesia, allowing practitioners to visualize in real time the nerve and the needle as it approaches the target, as well as the spread of local anesthetic in a space or plane adjacent to the target. Despite its potential as a visual aid, successful use of ultrasound depends largely on the skill of the practitioner. Proficiency requires training, as well as good hand–eye coordination and 3-dimensional spatial reasoning.

Needle visualization is critical for safety; an in-plane approach to the femoral nerve has been shown to result in less needle–nerve contact than an out-of-plane approach (Figures 2 and 3).13 Observing the spread of local anesthetic during injection may help clinicians determine the proximity of the needle to the nerve. If the needle is close to the nerve, but not inside it, local anesthetic will be seen spreading around the nerve or within a sheath (Figure 4). However, intraneural injection may be visualized as swelling of the nerve itself.14

Conclusion Three objective monitors can help regional anesthesiologists avoid intraneural injection. However, none is perfect: Ultrasound depends on the ability of the user; nerve stimulation is specific but not particularly sensitive; and injection pressure monitoring is sensitive but not specific. Because of the limitations of each of these monitors, we recommend that they be used simultaneously during PNBs to provide the most comprehensive protection possible against neurologic injury (Figure 8). We feel that approach is analogous to the simultaneous use of pulse oximetry, electrocardiography, and blood pressure and other routine monitoring during the administration of general anesthesia to avoid complications.

Figure 1. The use of electrical nerve stimulation to prevent needle–nerve contact and/or intraneural injection.

(A) Median nerve motor response with a “high” (0.48 mA) current intensity. (B) With the same needle position, the motor response is absent with a current intensity less than 0.2 mA, suggesting—but not proving—the needle tip is extraneural.

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Figure 2. In-plane needle insertion.

The needle is directed from the lateral aspect of the transducer, in the same plane as the ultrasound beam. In the corresponding sonographic image in a phantom, the needle is seen approaching the target (*).

Figure 4. The spread of local anesthetic between the tibial (TN) and common peroneal (CPN) branches of the sciatic nerve.

Note that the structure of each component nerve is intact and the outer epineurium (dotted lines) has not been violated.

Figure 3. Out-of-plane needle insertion.

The needle approaches the beam at right angles.

Therefore, only the small slice that crosses the beam is visible as a bright dot. (The asterisk marks the target.)

Figure 5. Compressed air injection technique.

A 20-mL syringe is filled with 10 mL of injectate and 10 mL of air. According to Boyleâ&#x20AC;&#x2122;s law, a compression of the gas by half of its original volume will double the pressure in the system (ie, increase the pressure at the needle tip by 1 atmosphere, or roughly 15 psi).

Maintaining the gas bubble at greater than half of its original volume should therefore prevent injection pressures of greater than 15 psi.

A N E ST H E S I O LO GY N E WS S P E C I A L E D I T I O N â&#x20AC;˘ O C TO B E R 2 0 1 4

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References 1.

Steinfeldt T, Graf J, Schneider J, et al. Histological consequences of needle-nerve contact following nerve stimulation in a pig model.

Anesthesiol Res Pract. 2011:591851.

2. Hadzic A, Dilberovic F, Shah S, et al. Combination of intraneural injection and high injection pressure leads to fascicular injury and neurologic deficits in dogs. Reg Anesth Pain Med. 2004;29(5):417-23.

3. Farber SJ, Saheb-Al-Zamani M, Zieske L, et al. Peripheral nerve injury after local anesthetic injection. Anesth Analg.

2013;117(3):731-739.

4. Gadsden JC, Choi JJ, Lin E, et al. Opening injection pressure consistently detects needle-nerve contact during ultrasound-guided interscalene brachial plexus block. Anesthesiology. 2014. [Epub ahead of print]

Figure 6. Pressure manometer showing opening pressure less than 15 psi.

5. Albrecht E, Kirkham KR, Taffé P, et al. The maximum effective needle-to-nerve distance for ultrasound-guided interscalene block: an exploratory study. Reg Anesth Pain Med. 2014;39(1):56-60.

6. Perlas A, Niazi A, McCartney C, et al. The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med. 2006;31(5):445-450.

7. Robards C, Hadzic A, Somasundaram L, et al. Intraneural injection with low-current stimulation during popliteal sciatic nerve block.

Anesth Analg. 2009;109(2):673-677.

8. Chan VWS, Brull R, McCartney CJL, et al. An ultrasonographic and histological study of intraneural injection and electrical stimulation in pigs. Anesth Analg. 2007;104(5):1281-1284 9. Tsai TP, Vuckovic I, Dilberovic F, et al. Intensity of the stimulating current may not be a reliable indicator of intraneural needle placement. Reg Anesth Pain Med. 2008;33(3):207-210.

10. Voelckel WG, Klima G, Krismer AC, et al. Signs of inflammation after sciatic nerve block in pigs. Anesth Analg.

2005;101(6):1844-1846.

11. Bigeleisen PE, Moayeri N, Groen GJ. Extraneural versus intraneural stimulation thresholds during ultrasound-guided supraclavicular block. Anesthesiology. 2009;110(6):1235-1243.

Figure 7. Pressure manometer showing graduated pressure thresholds of 15 to 20 psi and greater than 20 psi.

12. Wiesmann T, Borntrager A, Vassiliou T, et al. Minimal current intensity to elicit an evoked motor response cannot discern between needle-nerve contact and intraneural injection. Anesth Analg 2014;118:681-686.

13. Ruiz A, Sala-Blanch X, Martinez-Ocón J, et al. Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: a comparison between the out-of-plane versus the in-plane approaches. Rev Esp Anestesiol Reanim. 2014;61(2):73-77.

14. Macfarlane AJR, Bhatia A, Brull R. Needle to nerve proximity: what do the animal studies tell us? Reg Anesth Pain Med. 2011;36(3):290-302.

15. Theron PS, Mackay Z, Gonzalez JG, et al. An animal model of “syringe feel” during peripheral nerve block. Reg Anesth Pain Med. 2009;34(4):330-332.

16. Tsui BCH, Knezevich MP, Pillay JJ. Reduced injection pressures using a compressed air injection technique (CAIT): an in vitro study. Reg Anesth Pain Med. 2008;33(2):168-173.

Figure 8. Complementary monitoring strategy to reduce the risk for needle-induced nerve injury during peripheral nerve blocks.

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*from the date of manufacture â&#x20AC; or until solution is clear Important Safety Information The use of Revonto in the management of malig gnant hyperthermia crisis is not a substitute for previously known supportive measures. These measures mu ust be individualized, but it will usually be necessary to discontinue the suspect triggering agents, attend to increased oxygen requirements, manage the metabolic acidosis, institute cooling when nece essary, monitor urinary output, and monitor for electrolyte imbalance. Patients who receive i.v. dantrolene e sodium preoperatively should have vital signs monitored.

If patients judged malignant hyperthermia susceptible are administered dantrolene sodium preoperatively, anesthetic preparation must still follow a standa ard malignant hyperthermia susceptible regimen, including g the avoidance of known triggering agents. Mon nitoring for early clinical and metabolic signs of malignantt hyperthermia is indicated because attenuation of malignant hyperthermia, rather than prevention, is possible.

Despite initial satisfactory response to i.v. dantro olene there have been reports of fatality, which involve patients who could not be weaned from dantro olene after initial treatment. The administration of i.v. dantrolene is associated with loss of grip strength and weakness in the legs, as well as drowsiness and dizziness There have been reports of thrombophlebitis following administratio dizziness. administration on of intravenous dantrolene. dantrolene.

Tissue necrosis secondary to extravasation has been reported. Injection site reactions (pain, erythema, swelling), commonly due to extravasation, have been reported. Fatal and no on-fatal liver disorders of an idiosyncratic or hypersensitivity type may occur with dantrolene sodium thera apy.

To see the full prescribing information visit www.revonto.com. Š 2014 US WorldMeds, LLC. Revonto is a registered trademark of US WorldMeds, LLC.

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Current Concepts In the Understanding of Malignant Hyperthermia TAE W. KIM, MD Professor and Director of Quality Improvement Department of Anesthesiology University of Minnesota School of Medicine Staff Anesthesiologist University of Minnesota Childrenâ&#x20AC;&#x2122;s Hospital Minneapolis, Minnesota

NINA NAMI, MD Director, Department of Medical Education and Clinical Research Saint Barnabas Medical Center Livingston, New Jersey President, Malignant Hyperthermia Association of the United States Sherburne, New York

Clinical Associate Department of Anesthesiology The Johns Hopkins Hospital Baltimore, Maryland

The authors do not have any financial interest in any company nor do they endorse any products mentioned in this article.

M

alignant hyperthermia (MH) is a pharmacogenetic disorder

triggered by exposure to halogenated volatile anesthetic gases and succinylcholine.

The underlying mechanism for this potentially deadly condition involves the unregulated release of calcium from the sarcoplasmic reticulum into the myoplasm. The ryanodine receptor protein encoded by the RYR1 gene on chromosome 19q.13.1 forms the calcium channel (Figure 1).

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15

Exposure to anesthetic-triggering agents and, in rare cases, to physical exertion in the presence of high environmental temperature stimulates the unregulated release of calcium through the channel.1 This release can precipitate a metabolic chain reaction with generalized muscle contraction (rigidity) accompanied by the byproducts of metabolism: heat, carbon dioxide, and acidosis. The ensuing hypermetabolic state culminates in the exhaustion of the myocyte’s ability to maintain cellular integrity, resulting in rhabdomyolysis, hyperkalemia, and combined metabolic respiratory acidosis.

The only effective treatment for an MH crisis is the administration of dantrolene sodium,2 a hydantoin derivative first developed as a muscle relaxant.

Dr. Keith Ellis discovered that dantrolene acted on the intrinsic mechanism of skeletal muscle contraction and had no effect on cardiac or smooth muscle.3 The exact mechanism of action is unknown, except that the drug binds to the ryanodine receptor and interferes with the release of calcium into the myoplasm.

Determination of the incidence and prevalence of MH has been difficult. The disease itself is rare and may go unrecognized and, although the autosomal dominant pattern of inheritance imparts a 50% chance of passing the mutated gene to the offspring, the phenotypic manifestation is characterized by reduced penetrance and variable expressivity. The incidence of MH is reported to range from 1 in 3,000 to 1 in 50,000 anesthetics, with an occurrence among children of 1 in 5,000 to 1 in 10,000 anesthetics and adults of 1 in 50,000 anesthetics.4,5 Two studies examining MH in the United States found an estimated incidence rate of 11 MH patients per 1 million hospital discharges from

hospitals participating in the Nationwide Inpatient Sample (NIS) from 2000 to 2005 and a prevalence of 3.8 per 100,000 surgical patient discharges from pediatric hospitals participating in the Kids’ Inpatient Database (KID) for the years 2000, 2003, and 2006.6,7 A more recent study examining the KID database from 2000 to 2009 for pediatric patients with an International Classification of Diseases, Ninth Revision (ICD-9) code for MH and surgery found an MH prevalence of 1 in 10,000 surgical patients.8 One study examining MH in New York hospitals found a prevalence of 1 in 100,000 due to anesthesia in surgical patients.9 These differing results exemplify how the population being scrutinized can have a major influence in the final analysis. Therefore, the best approach to understanding the prevalence of MH is that it is a potentially lethal condition in every anesthetized patient until proven otherwise (Table 1).

Screening can be conducted using the clinical grading scale to evaluate the likelihood that a past or present intraoperative event truly represents an MH crisis.

A presumptive diagnosis of a patient having experienced an MH crisis is based on 6 physiologic processes and independent variables, such as reversal of MH signs and symptoms with the administration of dantrolene or creatine kinase greater than 20,000 units/L with the use of succinylcholine or greater than 10,000 units/L without the use of succinylcholine.10 A raw score is calculated and matched to the raw score range, which has a corresponding MH rank for different raw score values. The lowest raw score range is 0, which is equivalent to an MH rank of 1, meaning the description of the event has an “almost never” likelihood of being an MH crisis. A raw score range above 50 has an MH rank of 6, translating to a description of an event that is “almost certain” to be consistent with an MH crisis.10

Testing

Figure 1. Structural rendering of the ryanodine receptor protein.

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The gold standard for testing individuals at risk for MH or confirming a clinical diagnosis of MH is the caffeine halothane contracture test (CHCT) or the in vitro contracture test (IVCT in Europe). Eligible candidates undergo a muscle biopsy that obtains 2 g of tissue from one of the quadricep muscles using a nontriggering anesthetic technique and conducting the contracture test within 5 hours of harvesting the specimen.4 The procedure is performed 3 times for each test agent according to the standardized protocol of the North American Malignant Hyperthermia Group (NAMHG).11 Two sets of 3 muscle fascicles are dissected from the muscle specimen.11 Each fascicle is mounted in a separate bath of carbogenated Krebs-Ringer’s solution and exposed separately to 3% halothane and increasing concentrations of caffeine.11 A supramaximal electrical stimulation is applied to the muscle strip after exposure to halothane and after each change in concentration of caffeine.11 A force transducer is used to measure the isometric contraction. The sensitivity is

approximately 97% and specificity is 78%.12 However, the IVCT using the European Malignant Hyperthermia Group’s protocol has a sensitivity of 99% and a specificity of 93.6%.13 The difference in specificity may be due to the single exposure to 3% halothane used in the NAMHG protocol.12 Patients who have experienced a clinical episode of MH or significant rhabdomyolysis must wait at least 2 to 3 months to allow time for the muscles to completely recover.4 (Only 4 centers in the United States offer the test: the University of Minnesota, Wake Forest University, the Uniformed Services University of the Health Sciences, and the University of California, Davis; 1 center in Canada, Toronto General Hospital, does, as well. In Europe, there are 22 MH centers, mainly in Germany [6], France [3] and Italy [3].)

Molecular genetic testing remains a noninvasive and less-costly alternative to a muscle biopsy. The test often is used to confirm MH susceptibility (MHS) after muscle testing. Patients with a convincing history, such as a high clinical grading scale score, postmortem DNA testing for a suspected MH-related death, or a first-degree relative of a proband with a clinical history of MH, are eligible for genetic testing.4 However, unlike the muscle contracture test, a negative test does not exclude MHS. The protocol requires collection of a blood or tissue sample containing the patient’s DNA and delivery to a genetics laboratory for analysis, such as Prevention Genetics, LLC, in Marshfield, Wisconsin, or the DNA Diagnostics Center, in Pittsburgh.

To date, 2 genes have been identified as causal for MH: RYR1 and CACNA1S, which codes for the α1-subunit of the skeletal muscle dihydropyridine receptor L-type calcium channel. 4 RYR1 accounts for 70% to 80% of MHS patients, whereas CACNA1S accounts for 1%.4 Although more than 70% of individuals with a confirmed diagnosis of MH carry a DNA variant, genetic testing can identify only 25% to 30% of those with MHS.4 This statement may seem confusing, but reflects the real problem of having identified over 300 DNA variants for RYR1, but having only officially listed 32 as “causal” for MH. Most of the variants either represent polymorphisms or have unknown significance. The task at hand is to define the significance of these DNA variants in order to increase the sensitivity of genetic testing. Therefore, the test cannot be used for screening. It is most valuable when there has been either a positive contracture test or a “very likely” or higher classification of an MH episode. Also, patients found to have a variant of unknown significance present a clinical dilemma for their physician in regard to their MH status or may find themselves arbitrarily classified as MH-susceptibile based on possession of an RYR1 variant.

It should be noted that there tends to be a 10% discordance between the results of a muscle contracture test and a genetic test, which has yet to be explained.14 The cost of muscle contracture testing

Table 1. Signs of MH Tachycardia: early, nonspecific

Increasing EtCO2 temporarily responsive (early) or unresponsive (late) to increases in minute ventilation

Trunk or total body rigidity

Masseter muscle rigidity—“Jaws of Steel”— correlated with other signs of MH

Mixed respiratory/metabolic acidosis

Rise in temperature, especially when rapid and unexplainable (late sign)

Myoglobinuria

EtCO tCO2, e end-tidal d t da ca carbon bo d dioxide; o de; MH,, malignant a g a t hyperthermia ype t e a

and the low yield of genetic studies require careful consideration of candidates who will benefit the most from either test. Candidates should be evaluated by a knowledgeable physician or genetic counselor before testing. (Consultants are available through the Malignant Hyperthermia Association of the United States.)

In addition to diagnostic testing, the patient’s medical history may provide insight into whether he or she is at risk for MH. A variety of myopathies are associated with MHS. Patients with central core disease, multiminicore disease (MmD), and King-Denborough syndrome are well documented to be at risk for an MH crisis.15 A classic finding of both central core disease and MmD are characteristic cores in muscle biopsy specimens. All 3 conditions represent congenital myopathies associated with an RYR1 defect.15 Duchenne muscular dystrophy and mitochondrial disorders are not associated with mutations in RYR1, unlike many other myopathies. The pathophysiology of Duchenne and mitochondrial myopathies do not directly involve the ryanodine receptor. The important concept is that these patients may be at risk for an MH-like crisis from exposure to volatile halogenated gases and succinylcholine resulting in rhabdomyolysis and hyperkalemia through a similar mechanism without sharing a common genetic link.16,17

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Table 2. Acute Management Of an MH Crisisa Declare crisis: Call for help, MH cart

Notify surgical team: Determine best time to abort procedure, assist with active cooling of patient

Stop exposure to triggering agents: Discontinue volatile agents, hyperventilate with high fresh gas flows using 100% oxygen.

Do not change anesthesia machine.

Switch to nontriggering anesthetic technique: total IV anesthesia.

Administer 2.5 mg/kg of dantrolene in repeated doses based on clinical and laboratory response. Ryanodex is supplied in 20 mL vials containing 250 mg dantrolene sodium and 125 mg mannitol; generic dantrolene vials contain 20 mg of dantrolene and 3 g of mannitol. Mix with only preservative-free sterile water.

Obtain additional peripheral or central venous access as indicated.

Place arterial catheter for continuous monitoring of hemodynamics and vascular access for frequent blood sampling.

Place Foley catheter to monitor urine output.

Initiate and continue active cooling of patient as indicated.

Address metabolic and electrolyte derangements.

Transfer to intensive care unit for further treatment and continuation of dantrolene.

Call MH Hotline: (800) 644-9737 for emergency assistance.

MH, malignant hyperthermia a

www.mhaus.org/testing/centers. www aus o g/test g/ce te s Accessed ccessed January Ja ua y 16, 6, 2014.

0

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Clinical Presentation The importance of early recognition and treatment is reflected in previous studies of MH crises and patient outcomes. One of the earliest and most specific signs for MH has been an increase in end-tidal carbon dioxide despite increases in minute ventilation. Along with generalized muscle rigidity, the 2 signs are strongly indicative that the patient is experiencing an MH crisis.

Ironically, hyperthermia is not the earliest sign, which may be delayed. Once body temperature begins to rise, the rate of increase can be as much as 1째C to 2째C every 5 minutes if unchecked. A retrospective study demonstrated a 3-fold increase in complications associated with each 2째C increase in maximum temperature; a 30-minute delay in dantrolene administration resulted in a 1.6-fold increase in complications.17 Review of the North American Malignant Hyperthermia Registry between 1987 and 2006 illustrated the increased risk for cardiac arrest/death due to a longer period between anesthetic induction and maximum end-tidal carbon dioxide (216 vs. 87 min).17 Blood gas indices, maximum recorded temperature, and total dose of dantrolene administered were markedly abnormal in the 4 patients who died and represented the cases with delayed presentation or recognition and therefore a delayed response to treatment.17 In a retrospective study by Litman et al, 10 cases of MH were identified in the postoperative period, approximately 40 minutes after cessation of anesthetic gases.18 These were stated to be true, but quite rare, occurrences of MH.

Managing an MH Crisis The anesthetic management of an MH crisis is among the most intense clinical challenges an anesthesia provider can encounter (Table 2). Initial steps involve stopping the delivery of the triggering agent, such as sevoflurane, isoflurane, or desflurane (Figure 2). High fresh gas flow rates with 100% oxygen should be instituted to purge the anesthesia machine of any anesthetic gases as quickly as possible without disconnecting the patient. In addition, the surgeon and the rest of the team should be alerted to the crisis.

Dantrolene should be administered as soon as possible. The initial dose of dantrolene is 2.5 mg/kg, repeated as needed to control signs of the crisis. This in itself is a time-consuming task: gathering the vials, each containing only 20 mg of dantrolene and 3 g of mannitol, mixing with 60 mL of preservative-free sterile water, aspirating back into the 60-mL syringe, and injecting into the largest, free-flowing peripheral IV or central venous line. Also, placement of activated charcoal filters is recommended on the inspiratory and expiratory ports of the anesthesia machine to facilitate removal of triggering anesthetic gases from both the machine and patient (Figure 3). Assistance will be needed for obtaining additional IV and arterial access, placing a Foley catheter, and actively cooling the patient to a temperature of 38째C.

Figure 2. Malignant hyperthermia is a pharmacogenetic disorder caused by halogenated volatile anesthetic gases and succinylcholine. Š Tae W. Kim, MD.

Assessing response to therapy will require frequent blood sampling to ensure correction of metabolic derangements and to follow indicators of the severity of rhabdomyolysis, such as creatine kinase. Recrudescence is always a danger after successful treatment and therefore requires the patient to continue therapy in the ICU for at least 24 to 36 hours.

MH-susceptible patients may be anesthetized safely using a nontriggering anesthetic, such as regional or IV anesthesia. However, procedures requiring controlled ventilation may require the patient to be intubated. Intubation requires preparing an anesthesia machine by purging the system of residual volatile anesthetic agent with high fresh gas flows, while ventilating a 2- or 3-L breathing bag and/or replacing components of the breathing system with autoclaved or new parts and finally changing the patient breathing circuit. The last step should be performed immediately after the patient arrives in the operating room or procedure area. Preparation of the anesthesia machine should commence as soon as possible, as it is a labor-intensive process requiring as long as 104 minutes.19 A review article by Kim and Nemergut provides a table summarizing the steps involved in flushing different anesthesia machines.20 Additional information concerning anesthesia machine preparation can be found on the website of the Malignant Hyperthermia Association of the United States (at www.MHAUS.org/ healthcare-professionals/mhaus-recommendations/ anesthesia-workstation-preparation) or on those of the respective manufacturers.

The introduction of a new activated charcoal filter (Vapor-Clean, Dynasthetics) has refocused attention

Figure 3. Placement of activated charcoal filters at the inspiratory and expiratory ports can help remove traces of the triggering anesthetic gas. Š Tae W. Kim, MD.

on eliminating anesthetic gases using activated charcoal.21 These yellow filters are placed on the inspiratory and expiratory ports of the anesthesia machine.

The filters have been demonstrated to reduce the concentrations of sevoflurane, isoflurane, and desflurane to 5 ppm or lower within 2 minutes for 90 minutes.21 A study by Bilmen and Gillies demonstrated the effectiveness of these filters for 12 hours. They recommend using one filter on the inspiratory limb, flushing the anesthesia machine for 90 seconds with high fresh gas flows for 10 Lpm, replacing the breathing circuit and soda lime canister, and continuing with high fresh gas flows for at least 90 minutes before removing the filter or keeping the filter in place and reducing the gas flow to 3 Lpm.22 Also important, the vaporizers should be taped or removed to avoid inadvertent use, which might overwhelm the absorptive capacity of the filters.

In addition, the FDA recently approved Ryanodex (Eagle Pharmaceuticals), a new formulation of dantrolene incorporating nanosuspension technology.

The new drug is packaged in 250 mg vials as a lyophilized powder requiring 5 mL of preservative-free sterile water for reconstitution, yielding a 50 mg/mL concentration. Also, the new formulation contains 125 mg per vial of mannitol as opposed to 3 g per vial of mannitol and 20 mg of dantrolene. Ten seconds of vigorous

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Table 3. Cases of Awake MH Anecdotal cases: heat exposure with exercise misdiagnosed as heat stroke.

Subset of those with MH susceptibility can develop MH without anesthesia; have RYR1 variant.

In 7 pediatric patients with susceptibility to MH who had awake MH event and subsequently died, findings included viral illness, high environmental temperature, and physical or emotional stress.

Based on references 24 24-26.

26.

agitation is stated to yield a uniform orange-colored suspension ready for immediate use or storage for up to 6 hours. This would enable an anesthesia provider to deliver the first dantrolene dose of 2.5 mg/kg in a 100 kg patient with only one vial and minimal effort in comparison to previous formulations. Administration of dantrolene is stated to be compatible with IV infusion of 0.9% sodium chloride injection, or 5% dextrose injection, but not for reconstitution. Manufacturer warnings and precautions and adverse reactions are the same as for other preparations of dantrolene and specifically refer to the drug’s pH of approximately 10.3 and ability to induce muscle weakness. Unfortunately, at the time of this review the drug had just been released for clinical use so little is known about its real-world application and effectiveness.

Awake MH There have been anecdotal reports of patients experiencing MH or MH-like signs without anesthesia (Table 3). These patients will usually trigger upon exposure to heat in conjunction with exercise and may be misdiagnosed as having simple heat stroke. In some cases of so-called “awake MH,” the patient may have an underlying myopathy, as well as a ryanodine receptor mutation. Gronert et al. reported the first confirmed case of awake MH in 1980.23 The patient was a 42-year-old man who experienced periodic body cramps with high fevers. A positive muscle biopsy proved him to have MHS. His daily activities included self-monitoring for signs and symptoms of MH and self-treatment with oral dantrolene. Additionally, after undergoing a nontriggering anesthetic technique for surgery, he experienced fevers postoperatively, which were successfully treated with dantrolene.

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Increasing evidence indicates that a subset of MHS individuals can develop signs of MH without anesthesia. A more recent case involved a 6-year-old boy who died of fulminant MH.24 The child developed lower extremity rigidity, trismus, and fever to 108.9°F after playing in a splash pool. He was rushed to the hospital and emergently intubated on arrival with succinylcholine for respiratory distress and questionable seizure activity. He experienced cardiac arrest, which was unresponsive to treatment. A postmortem DNA analysis demonstrated a novel RYR1 variant. The father shared the same genetic defect and was found by muscle contracture testing to be strongly positive for MHS; he also was diagnosed with central core disease.

A review article reported the deaths of 7 MHS pediatric patients who experienced an awake MH event.25 Many of these children had been diagnosed clinically and had a positive muscle contracture test and a positive test for a causal genetic mutation. Testing of family members with the same RYR1 variants were found to have positive contracture tests consistent with MHS or in vitro testing demonstrating a 2-fold increase in response to caffeine exposure.

The common findings among these children were viral illnesses, high environmental temperatures, and stress at the time of the awake MH event and death.

These findings seem to corroborate the effect of stress in an earlier report of awake MH episodes in male patients with confirmed MHS.26 It was noted that “extreme physical or emotional stress or fatigue resulted in aching joints, malaise, fevers of 40°C or more, and soaking sweats.”

Comparison of the experiences of awake MH individuals to those cited in a paper on postoperative MH may suggest a link between awake MH and the occurrence of MH in the postoperative period. A retrospective study identified 10 patients having experienced MH out of 528 suspected cases, leading to the conclusion that postoperative MH does occur in a rare subset of MHS patients, with a prevalence of 1.9% in the study population.27 All 10 patients had received a volatile anesthetic agent and 5 had received succinylcholine.

The case duration was from 35 to 660 minutes. All patients experienced an MH episode within 40 minutes, however the majority of patients demonstrated signs and symptoms within 15 minutes. The times were measured from when the anesthesiologist turned off the anesthetic agent to when the patient manifested signs of MH in the postanesthesia care unit.

Studies of MH-susceptible swine have found them to trigger because of emotional or physical stress, and some have hypothesized that the same may be the case in humans, although that contention has not been studied or proven. A notable difference is that MH-susceptible swine are homozygous for a single mutation in the RYR1 gene, while almost all humans are heterozygous and many different mutations or DNA variants have been linked to MH susceptibility.

However, the role of stressors, such as return of mucle

activity in conjunction with residual anesthetic levels in the immediate postoperative period, pain, and temperature instability, may offer some insight into a shared mechanism for awake MH and postoperative MH. The stress placed by any one or combination of factors may be sufficient to trigger MH or may add to the existing stressors to overcome the threshold for sparking a crisis.26-28 More studies are needed to verify or refute if a relationship exists between these 2 rare subtypes.

Conclusion MH is a rare and potentially fatal pharmacogenetic disorder. Susceptibility to malignant hyperthermia is commonly discovered after an MH crisis is triggered by exposure to halogenated volatile anesthetic agents or succinylcholine. The clinical grading score is a useful tool for making a clinical assessment of whether a patient has experienced MH. However, the gold standard for testing is the CHCT. For those individuals who are biologically related to a proband, the genetic test offers a minimally invasive, low-cost alternative to the muscle biopsy. Because RYR1 is so large, and

there are so many DNA variants that have yet to be characterized, more research is necessary to clarify who is—and is not—at risk for MH. A recent article by Gonsalves et al examined the exome sequencing data of 870 volunteers in the ClinSeq study.29 Of 4 RYR1 variants predicted to be pathogenic for MHS, 3 were found in 3 participants without medical or family histories of MHS. The study found a prevalence of 1 in 340 control patients for the pathologic RYR1 mutations. The essential question now emerging, not only for MH but many other disorders, is when does a DNA variant lead to clinical manifestations of a disorder?

For those patients already identified, anesthesia care can be safely managed with a nontriggering anesthetic technique, a well-prepared anesthesia machine and/or the use of activated charcoal filters. The relation of MH susceptibility to heat and exercise is a phenomenon that is suggestive but requires more study.

The FDA approval of Ryanodex may alleviate many of the logistic headaches and simplify the treatment of MH. The phenomenon of awake MH is still being investigated and may in the future require changes in practice to anticipate, prevent, and manage such cases.

References 1.

Capacchione JF, Muldoon SM. The relationship between exertional heat illness, exertional rhabdomyolysis, and malignant hyperthermia. Anesth Analg. 2009;109(4):1065-1069.

10.

Larach MG, Localio AR, Allen GC, et al. A clinical grading scale to predict malignant hyperthermia susceptibility.

Anesthesiology. 1994;80(4):771-779.

2.

Harrison GG. Control of the malignant hyperpyrexic syndrome in MHS swine by dantrolene sodium. Br J Anaesth.

1975;47(1):62-65.

11.

Larach MG. Standardization of the caffeine halothane muscle contracture test. North American Malignant Hyperthermia Group. Anesth Analg. 1989;69(4):511-515.

3.

Ellis KO, Castellion AW, Honkomp LJ, et al. Dantrolene, a direct acting skeletal muscle relaxant. J Pharm Sci. 1973;62(6):948-951.

12.

4.

Rosenberg H, Sambuughin N, Riazi S, et al. Malignant hyperthermia susceptibility. 2003 Dec 19 [Updated 2013 Jan 31]. In: Pagon RA, Adam MP, Bird TD, et al., eds. Gene Reviews [Internet]. Seattle: University of Washington, 1993-2013.

Allen GC, Larach MG, Kunselman AR. The sensitivity and specificity of the caffeine-halothane contracture test: a report from the North American Malignant Hyperthermia Registry. The North American Malignant Hyperthermia Registry of Malignant Hyperthermia Association of the United States. Anesthesiology.

1998;88(3):579-588.

13.

Ørding H, Brancadoro V, Cozzolino S, et al. In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European Malignant Hyperpyrexia Group: results of testing patients surviving fulminant MH and unrelated low-risk subjects. Acta Anaesthesiol Scand. 1997;41(8):955-966.

14.

Robinson RL, Anetseder MJ, Brancadoro V, et al. Recent advances in the diagnosis of malignant hyperthermia susceptibility: how confident can we be of genetic testing?

Eur J Hum Genet. 2003;11(4):342-348.

15.

Brislin RP, Theroux MC. Core myopathies and malignant hyperthermia susceptibility: a review. Paediatr Anaesth.

2013;23(9):834-841.

16.

Larach MG, Gronert GA, Allen GC, et al. Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg.

2010;110(2):498-507.

17.

Larach MG, Brandom BW, Allen GC, et al. Cardiac arrests and deaths associated with malignant hyperthermia in North America from 1987 to 2006: a report from the North

5.

Hogan K. The anesthetic myopathies and malignant hyperthermias. Curr Opin Neurol. 1998;11(5):469-476.

6.

Rosero EB, Adesanya AL, Timarra CH, et al. Trends and outcomes of malignant hyperthermia in the United States 2000-2005. Anesthesiology. 2009;110(1):89-94.

7.

8.

9.

Li G, Brady JE, Rosenberg H, et al. Excess comorbidities associated with malignant hyperthermia diagnosis in pediatric hospital discharge records. Paediatr Anaesth.

2011;21(9):958-963.

Salazar JH, Yang J, Shen L, et al. Pediatric malignant hyperthermia: risk factors, morbidity, and mortality identified from the Nationwide Inpatient Sample and Kids’ Inpatient Database. Paediatr Anaesth. 2014 Jun 28. doi: 10.1111/pan.12466.

[Epub ahead of print].

Brady JE, Sun LS, Rosenberg H, et al. Prevalence of malignant hyperthermia due to anesthesia in New York State, 2001-2005.

Anesth Analg. 2009;109(4):1162-1166.

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American Malignant Hyperthermia Registry of the Malignant Hyperthermia Association of the United States. Anesthesiology.

2008;108(4):603-611.

24.

Lavezzi WA, Capacchione JF, Muldoon SM, et al. Case report: Death in the emergency department: an unrecognized awake malignant hyperthermia-like reaction in a six-year-old. Anesth Analg. 2013;116(2):420-423.

Litman RS, Flood CD, Kaplan RF, et al. Postoperative malignant hyperthermia: an analysis of cases from the North American Malignant Hyperthermia Registry. Anesthesiology.

2008;109(5):825-829.

25.

Brandom BW, Muldoon SM. Unexpected MH deaths without exposure to inhalation anesthetics in pediatric patients.

Paediatr Anaesth. 2013;23(9):851-854.

19.

Gunter JB, Ball J, Than-Win S. Preparation of the Drager Fabius anesthesia machine for the malignant hyperthermia susceptible patient. Anesth Analg. 2008;107(6):1936-1945.

26.

20.

Kim TW, Nemergut ME. Preparation of modern anesthesia workstations for malignant hyperthermia-susceptible patients: a review of past and present practice. Anesthesiology.

2011;114(1):205-212.

Groom L, Muldoon SM, Tang ZZ, et al. Identical de novo mutation in the type 1 ryanodine receptor gene associated with fatal, stress-induced malignant hyperthermia in two unrelated families. Anesthesiology. 2011;115(5):938-945.

27.

Gronert GA, Tobin JR, Muldoon S. Malignant hyperthermia: human stress triggering. Biochim Biophys Acta. 2011; 1813(12):2191-2192.

28.

MacLennan DH, Zvaritch E. Response to “Malignant Hyperthermia-human stress triggering” in reference to original article “Mechanistic models for muscle diseases and disorders originating in the sarcoplasmic reticulum” Biochim Biophys Acta. 2011;1813:2193-2194.

29.

Gonsalves SG, Ng D, Johnston JJ, et al; NISC Comparative Sequencing Program. Using exome data to identify malignant hyperthermia susceptibility mutations. Anesthesiology.

2013;119(5):1043-1053.

18.

21.

Birgenheier N, Stoker R, Westenskow D, et al. Activated charcoal effectively removes inhaled anesthetics from modern anesthesia machines. Anesth Analg. 2011;112(6):1363-1370.

22.

Bilmen JG, Gillies RI. Clarifying the role of activated charcoal filters in preparing an anaesthetic workstation for malignant hyperthermia-susceptible patients. Anaesth Intensive Care.

2014;42:51-58.

23.

Gronert GA, Thompson RL, Onofrio BM. Human malignant hyperthermia: awake episodes and correction by dantrolene.

Anesth Analg. 1980;59(5):377-378.

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When MH strikes,

Keep cool in the crisis with administration in

LESS THAN 1 MINUTE

ADVANCING THE STANDARD IN MALIGNANT HYPERTHERMIA (MH) TREATMENT. RYANODEX® (dantrolene sodium) for injectable suspension is changing how MH is treated.

• Less time for reconstitution and administration – Less than 1 minute for a loading dose (2.5 mg/kg) of dantrolene sodium in an MH crisis1,2 • Less risk of complications with less fluid – Over 99% less sterile water for injection than other dantrolene sodium IV treatments3-5 • Less effort to stay cool in an MH crisis – 1 vial provides a loading dose for patients up to 100 kg and can be administered by 1 healthcare professional (eg, an anesthesia provider)1,3 To request that RYANODEX® be stocked in your institution or obtain ordering information, visit RYANODEX.com/anes or call 855.318.2170.

References: 1. Data on file. Eagle Pharmaceuticals, Inc. 2. Managing an MH crisis. Malignant Hyperthermia Association of the United States website. http://www.mhaus.org/healthcareprofessionals/managing-a-crisis.

Accessed June 18, 2014. 3. RYANODEX [package insert]. Woodcliff Lake, NJ: Eagle Pharmaceuticals, Inc.; 2014. 4. Dantrium Intravenous [package insert]. Rochester, MI: JHP Pharmaceuticals, LLC; 2008. 5. Revonto [package insert]. Louisville, KY: US WorldMeds, LLC; 2011.

Please see Brief Summary of full Prescribing Information on the following page. © 2014 Eagle Pharmaceuticals, Inc. All rights reserved.

50 Tice Blvd, Suite 315 Woodcliff Lake, NJ 07677 (201) 326-5300 RYN14-0027-01 10/2014

INDICATION RYANODEX® (dantrolene sodium) for injectable suspension is indicated for the treatment of malignant hyperthermia in conjunction with appropriate supportive measures, and for the prevention of malignant hyperthermia in patients at high risk.

IMPORTANT SAFETY INFORMATION RYANODEX® is not a substitute for appropriate supportive measures in the treatment of malignant hyperthermia (MH), including: • Discontinuing triggering • Instituting cooling when necessary anesthetic agents • Administering diuretics to prevent • Increasing oxygen late kidney injury due to myoglobinuria (the amount • Managing the of mannitol in RYANODEX® is metabolic acidosis insufficient to maintain diuresis)

RYANODEX® (dantrolene sodium) for injectable suspension, for intravenous use.

Brief Summary of Prescribing Information. See Package Insert For Full Prescribing Information INDICATIONS AND USAGE RYANODEX® is indicated for the: • Treatment of malignant hyperthermia in conjunction with appropriate supportive measures (see Dosage and Administration) • Prevention of malignant hyperthermia in patients at high risk.

DOSAGE AND ADMINISTRATION (Selected Information) In addition to RYANODEX treatment, institute the following supportive measures: • Discontinue use of malignant hyperthermia (MH)-triggering anesthetic agents (i.e., volatile anesthetic gases and succinylcholine).

• Manage the metabolic acidosis • Institute cooling when necessary • Administer diuretics to prevent late kidney injury due to myoglobinuria (the amount of mannitol in RYANODEX is insufficient to maintain diuresis) Administer RYANODEX by intravenous push at a minimum dose of 1 mg/kg. If the physiologic and metabolic abnormalities of MH continue, administer additional intravenous boluses up to the maximum cumulative dosage of 10 mg/kg.

If the physiologic and metabolic abnormalities reappear, repeat RYANODEX dosing by intravenous push starting with 1 mg/kg.

Dosage for Prevention of Malignant Hyperthermia The recommended prophylactic dose of RYANODEX is 2.5 mg/kg administered intravenously over a period of at least 1 minute, starting approximately 75 minutes prior to surgery. Avoid agents that trigger MH. If surgery is prolonged, administer additional individualized RYANODEX doses during anesthesia and surgery.

Dosage for Pediatric Patients The recommended weight-based dose of RYANODEX for pediatric patients in the treatment and prevention of MH is the same as for adults for these indications (see Dosage and Administration).

Reconstitution and Administration Instructions The supplied lyophilized powder must be reconstituted prior to administration: Reconstitute each vial of RYANODEX lyophilized powder by adding 5 mL of sterile water for injection (without a bacteriostatic agent).

Do not reconstitute with any other solution (e.g., 5% dextrose injection, 0.9% sodium chloride injection).

Shake the vial to ensure an orange-colored uniform suspension. Visually inspect the vial for particulate matter and discoloration prior to administration.

Must use the contents of the vial within 6 hours after reconstitution. Store reconstituted suspensions at controlled room temperature (68°F to 77°F or 20°C to 25°C).

(For complete Dosage and Administration Section, see full Prescribing Information)

dysphasia. Assess patients for difficulty swallowing and choking.

Somnolence and Dizziness Somnolence and dizziness can occur following administration of RYANODEX and may persist up to 48-hours post-dose. Patients should not be permitted to ambulate without assistance until they have normal strength and balance.

Patients must not operate an automobile or engage in other hazardous activities for 48-hours post-dose.

The concomitant use of sedative agents with RYANODEX may increase the risk of somnolence and dizziness.

Potential for Tissue Necrosis with Extravasation Care must be taken to prevent extravasation of RYANODEX into the surrounding tissues due to the high pH of the reconstituted RYANODEX suspension and potential for tissue necrosis.

ADVERSE REACTIONS Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In a study designed to evaluate the safety and tolerability of RYANODEX, healthy volunteers were randomly assigned to receive treatment with RYANODEX or an active comparator at doses ranging from 1 mg/kg to 2.5 mg/kg.

• The RYANODEX dose was infused over the course of 1 minute for each of the doses evaluated.

• The active comparator was an injectable formulation of dantrolene sodium that differed from RYANODEX in that it contained dantrolene sodium and mannitol at concentrations of 0.33 mg/mL and 50 mg/mL, respectively, when reconstituted according to the product’s prescribing information. The active comparator was infused at a rate that administered 20 mg of dantrolene per minute for each of the doses evaluated.

Table 1 displays the most common adverse events in this study. These data are not an adequate basis for comparison of the types or frequencies of adverse event types between RYANODEX and the dantrolene sodium comparator.

Adverse events increased in frequency with increasing doses in the trial, but did not differ in frequency between the two treatment groups.

RYANODEX-treated subjects were more likely to report immediate adverse events of flushing, dystonia, and dysphagia than those receiving the active comparator.

In all dose groups, hand grip strength declined after dosing. In general, the decline in hand grip strength was more pronounced and occurred more rapidly in the RYANODEX-treated subjects in the 1.0, 1.75, 2.0 and 2.25 mg/kg treatment groups. In the 2.5 mg/kg treatment group, the decline in hand grip strength both in amount and duration was similar between the two treatment groups.

Table 1: Adverse Events in Healthy Volunteers Number(%) of subjects

CONTRAINDICATIONS None.

WARNINGS AND PRECAUTIONS Muscle Weakness RYANODEX is associated with skeletal muscle weakness. The administration of RYANODEX in human volunteers has been associated with loss of grip strength and weakness in the legs.

Patients should not be permitted to ambulate without assistance until they have normal strength and balance.

RYANODEX has been associated with dyspnea, respiratory muscle weakness, and decreased inspiratory capacity. Monitor patients for the adequacy of ventilation.

RYANODEX has been associated with

RYANODEX [N=30]

DANTROLENE SODIUM COMPARATOR [N=31]

Flushing

8 (27)

1 (3)

Somnolence

5 (17)

4 (13)

Dysphonia

4 (13)

1 (3)

Dysphagia

3 (10)

4 (13)

Nausea

3 (10)

3 (10)

Feeling abnormal

3 (10)

3 (10)

Headache

1 (3)

4 (13)

Vomiting

1 (3)

2 (6)

Vision blurred

1 (3)

1 (3)

Pain in extremity

1 (3)

1 (3)

Muscular Weakness/ Asthenia

1 (3)

1 (3)

Atrioventricular block

1 (3)

0

Tachycardia

1 (3)

0

Infusion site pain

1 (3)

0

Dizziness

1 (3)

0

Postmarketing Experience The following adverse reactions have been identified during postapproval use of another formulation of dantrolene sodium for injection.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Pulmonaryy Edema There have been reports of pulmonary edema developing during the treatment of malignant hyperthermia crises with another dantrolene sodium dosage form. The contributory effect of the diluent volume and mannitol in these cases is not known.

Thrombophlebitis p and Tissue Necrosis There have been reports of thrombophlebitis following administration of intravenous dantrolene. Tissue necrosis secondary to extravasation has been reported (see Warnings and Precautions).

Hypersensitivity/Anaphylactic yp y p y Reactions There have been reports of urticaria and erythema possibly associated with the administration of dantrolene sodium for injection.

Anaphylaxis has been reported.

Injection j Site Reactions Injection site reactions including pain, erythema, and swelling, commonly due to extravasation, have been reported.

DRUG INTERACTIONS Calcium Channel Blockers Cardiovascular collapse in association with marked hyperkalemia has been reported in patients receiving dantrolene in combination with calcium channel blockers. The concomitant use of RYANODEX and calcium channel blockers is not recommended during the treatment of malignant hyperthermia.

Muscle Relaxants The concomitant administration of RYANODEX with muscle relaxants may potentiate the neuromuscular block.

Antipsychotics and Antianxiety Agents The concomitant administration of RYANODEX with antipsychotic and antianxiety agents may potentiate their effects on the central nervous system (see Warnings and Precautions).

USE IN SPECIFIC POPULATIONS Pregnancy Pregnancy g y Category g yC Adequate and well controlled studies have not been conducted with RYANODEX in pregnant women. However, animal reproduction studies have been conducted with dantrolene sodium. In these studies, dantrolene sodium administered to rats and rabbits produced embryolethality (rabbits) and decreased pup survival (rats) at doses seven times the human oral dose.

RYANODEX should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Labor and Delivery In one uncontrolled study, 100 mg per day of prophylactic oral dantrolene sodium was administered to term pregnant patients awaiting labor and delivery. Dantrolene readily crossed the placenta, with maternal and fetal whole blood levels approximately equal at delivery; neonatal levels then fell approximately 50% per day for 2 days before declining sharply. No neonatal

respiratory and neuromuscular side effects were observed in this study.

Nursing Mothers Dantrolene is present in human milk. In one case report, low dantrolene concentrations (less than 2 micrograms per milliliter) were measured in the breast milk of a lactating woman during repeat intravenous dantrolene administration over 3 days. Because of the potential for serious adverse reactions of respiratory depression and muscle weakness in nursing infants from dantrolene, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use The safety and efficacy of RYANODEX in the treatment and prevention of malignant hyperthermia in pediatric patients is based on clinical experience with other intravenous dantrolene sodium products, which suggests adult weight-based doses are appropriate for pediatric patients.

Geriatric Use Clinical studies of RYANODEX did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

OVERDOSAGE Overdosage Symptoms Overdosage symptoms include, but are not limited to, muscular weakness and alterations in the state of consciousness (e.g., lethargy, coma), vomiting, diarrhea, and crystalluria.

Management of Overdosage Employ general supportive measures for acute overdosage of RYANODEX. PATIENT COUNSELING INFORMATION Inform patients, their families, or their caregivers of the following: Muscle Weakness Muscle weakness (i.e. decrease in grip strength and weakness of leg muscles, especially walking down stairs) is likely to occur with the use of RYANODEX. Patients should be provided assistance with standing and walking until their strength has returned to normal (see Warnings and Precautions).

Difficultyy Swallowingg Caution is indicated at meals on the day of administration because difficulty swallowing and choking have occurred with the use of dantrolene sodium products in general; dysphagia has been reported with the use of RYANODEX (see Warnings and Precautions).

Dizziness and Somnolence The use of RYANODEX has been associated with dizziness and somnolence. (see Warnings and Precautions).

Drivingg or Operating p g Machineryy Symptoms such as “lightheadedness” may occur.

Since some of these symptoms may persist for up to 48 hours, patients must not operate an automobile or engage in other hazardous activity during this time (see Warnings and Precautions).

Revised: 7/2014 Marketed by: Eagle Pharmaceuticals, Inc. Woodcliff Lake, NJ 07677

© 2014 Eagle Pharmaceuticals, Inc. All rights reserved.

50 Tice Blvd, Suite 315 Woodcliff Lake, NJ 07677 (201) 326-5300 8/2014

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Perioperative Management of Patients With Coronary Stents: Considerations for the Anesthesiologist The author has no relevant financial disclosures.

Image below is XIENCE V, a drug-eluting stent made by Abbott.

©2011 Abbott Laboratories. All Rights Reserved.

PRIYA A. KUMAR, MD Professor of Anesthesiology University of North Carolina School of Medicine Chapel Hill, North Carolina

P

ercutaneous coronary intervention (PCI) is a coronary revascularization technique with about 600,000 procedures per year being performed in the United States. It includes balloon angioplasties, which may or may not be combined with the placement of coronary stents.

The frequency of PCIs has increased dramatically over the past 2 decades, and stents are currently being placed in over 80% of these procedures. Not surprisingly, approximately 5% to 20% of patients with coronary stents placed within 2 years may present for non-cardiac surgery.

In order to prevent major adverse cardiovascular events (MACE) and safely manage these patients, it is imperative for perioperative physicians to be familiar with stent dynamics. They should have a clear understanding of the indicatiosn and importance of antiplatelet therapy (APT) for the prevention of stent thrombosis (ST). The patient’s risk for bleeding must be counterbalanced against the risk for life-threatening ST in patients on APT. It is essential that the entire perioperative team have a clear understanding that early identification, vigilant care, and rapid triage can prevent catastrophic outcomes in pateitns who develop ST.

History Since Gruentzig’s pioneering success at percutaneous transluminal coronary balloon angioplasty in 1977,1 stent technology has undergone a tremendous evolution. Stand-alone balloon angioplasties have high complication rates ranging between 15% and 60%, resulting

in substantial morbidity. They are associated with a risk of early vessel closure due to elastic recoil and late inflammatory restenosis; hence the use of angioplasty alone without stenting is limited.

Bare metal stents (BMS) were introduced in the 1980s to help avoid the shortcomings of balloon dilatations.

They were approved by the FDA in 1993. These devices function as vascular scaffolds and were regarded as a major advance in the nonsurgical management of coronary artery disease. Although BMS reduced the rates of restenosis, coronary artery recoil, and dissection, they carried their own problems. Stent implantation, which induces trauma to the vessel wall, initiates complex interactions between the vessel wall, stent surface, and blood components, leading to thrombogenesis and neointimal hyperplasia, much like the formation of scar tissue.

Neointimal hyperplasia, which in turn resulted in in-stent restenosis (ISR), affects 10% to 30% of these patients over the course of 3-6 months. In coronary arteries, even a small amount of hyperplastic tissue can significantly reduce the luminal diameter, resulting in gradual stent occlusion and ischemia. As a result, currently only about 25% of all stents implanted during PCIs are BMS.2 In the early 2000s, drug-eluting stents (DESs) were introduced as a potential solution for the prevention of

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25

ISR. The metallic scaffold was coated with a drug delivery polymer embedded with a pharmacologic agent to discourage scar tissue formation. The antiproliferative drugs (taxus and limus families) used to coat the stents were successful in preventing the proliferation of smooth muscle and markedly reduced the rates of restenosis to a range of 5% to 8%. In 2010, approximately 75% of stents implanted during PCI were DES2;however, the success of DESs came with a price. Whereas re-endothelialization after a BMS occurs within the first 6 to 7 months of implantation, the first-generation DESs may not be fully endothelialized even after 3 years.3 The coating of immunosuppressive and antiproliferative pharmacologic agents on DESs interferes with and delays the disrupted endothelium from healing. This leaves the subendothelial substrate exposed to the circulating platelets and inflammatory mediators for prolonged periods of time. Collagen in the exposed subendothelium is the most potent stimulus for platelet activation. As a result, late ST is a problem in these patients. While ISR is a pathology that evolves gradually over a period of 6 to 9 months, ST is an abrupt thrombotic vessel occlusion that can lead to an acute myocardial infarction with a mortality of 10% to 30%.

It is believed that stent architecture, flexibility, apposition to the coronary vessel wall, its polymer coating, and the choice of pharmacologic agent may play a significant role in the re-endothelialization process for an improved safety profile (Figure). The currently available DESs include those discussed here.

FIRST-GENERATION DESS First-generation DESs consist of a stainless steel metallic stent platform coated with a polymer that elutes the antiproliferative pharmacologic agent. Sirolimus is an immunosuppressive compound that reduces neointimal hyperplasia. Elution off the sirolimus platform is complete in about 6 weeks. Paclitaxel is an agent that has antiproliferative and cytotoxic properties; 10% of the drug is released in the first 10 days, and the remainder elutes indefinitely.

SECOND-GENERATION DESS Second-generation DESs comprise thinner, more radiopaque alloy and flexible cobalt-chromium or platinum-chromium alloy struts coated with a biocompatible polymer with superior re-endothelialization kinetics.

Zotarolimus inhibits smooth-muscle cell proliferation and completely disapppears after full elution. Everolimus, simlar to sirolimus in anti-proliferative and immunosuppressive properties, is more lipophilic, allowing rapid absorption into the arterial wall.

NEXT-GENERATION STENTS Stent technology is undergoing an explosion of research and refinement with the evolution of next-generation stents for increased biocompatibility. The development of antibody-coated stents, which attract circulating endothelial progenitor cells to enhance the repair of

26

A N E ST H E S I O LO GY N E WS .CO M

endothelial cells, is now being explored.4,5 Novel techniques aimed at developing bioabsorbable polymers are under way to speed healing delayed by the polymers.6 Similarly, the development of hollow, drug-filled BMS is being explored as a way to eliminate the need for the polymer. The theoretical advantages of completely bioabsorbable stents, which disappear over time, are enticing, and such devices currently are being evaluated.7

EARLY REPORTS

OF

STENT THROMBOSIS

As a result of several deaths from ST, the FDA issued a warning in 2003. Similarly, reports of acute ST after noncardiac surgery began to appear, particularly in patients with recently implanted DESs, which were associated with significant perioperative morbidity and death. Patient compliance with APT was crucial for lowering this risk. As a result, in 2007, the American College of Cardiology/American Heart Association (ACC/AHA) modified their guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery.8 The groups recommended that APT should be continued and elective surgery be postponed for 4 to 6 weeks after placement of a BMS and for 1 year after stent implantation in patients with DESs. They also recommended that whenever possible, urgent surgeries should be performed with the continuation of APT, although doing so may increase the risk for surgical bleeding. It is generally agreed that the risk for ST outweighs the risk for bleeding in patients with recently implanted stents.

In 2009, the American Society of Anesthesiologists (ASA) issued a practice alert in accordance with the ACC/AHA recommendations.9 The ASA supported the 2007 ACC/AHA recommendation, and agreed that selected patients at high risk for ST should continue APT beyond the recommended time periods. Some experts believe that antiplatelet agents with short half-lives, such as abciximab (Reopro, Janssen/Eli Lilly), tirofiban (Aggrastat, Medicure Pharma), and eptifibatide (Integrilin, Millennium Pharmaceuticals/Schering Plough), may be used in selective cases to bridge the gap between surgery and the discontinuation of APT. Cardiologists routinely recommend post-PCI APT according to the ACC/AHA 2011 guidelines for PCI.10 As already mentioned, ST is a sudden devastating complication that can lead to MI or death. It may result from stent malposition, coronary dissection, or incomplete endothelial healing in the face of withdrawal of APT. According to the Academic Research Consortium,11 for the purposes of consistency with reporting, ST can be classified according to its timing of occurrence as: • acute ST, T which occurs within 24 hours of stenting; • subacute ST, T which occurs from 24 hours to 30 days of stenting; • late ST, T which occurs from 31 days to 1 year of stenting; or • very-late ST, T which occurs 1 year after stenting.

The FDA has issued a policy outlining patients suitable for stent insertion, considered to be those whose 3-year risk for thrombosis is below 2%.12 The approved

indications include stable patients without comorbid conditions (such as diabetes, renal insufficiency, MI, <30% ejection fraction, left main coronary lesion) with short lesions (28-30 mm), noncomplex lesions, or native coronary lesions. In reality, only a minority (25%-40%) of patients meets those criteria and the majority of coronary stents are placed in “off-label” patients, which places them in the high-risk category.

Activation of platelets is recognized as the primary source of ST. Multiple pathways must be blocked in order to achieve effective APT. It is well known that there is significant crosstalk between the various receptors on the surface of the platelets; hence, dual antiplatelet therapy (DAPT) is currently recommended as the cornerstone of anti-thrombotic prophylaxis.10 The antiplatelet agents most frequently used consist of aspirin and clopidogrel, both of which are irreversible platelet inhibitors, have been extensively studied, and have the most favorable risk–benefit profile. Both aspirin and clopidogrewl (Plavix, Bristol-Myers Squibb/Sanofi) may be partially ineffective in as many as 30% of patients.

Pharmacogenomic and genetic polymorphism mechanisms play a major role in this drug resistance. With a half-life of 6 hours, clopidogrel is a prodrug that must be metabolized to the active drug in the liver by cytochrome P450. Genetic variability and interaction with other drugs metabolized by this mechanism may interfere with the effectiveness of clopidogrel. Genetic testing for drug resistance is routine in some institutions to tailor the choice of ATP in high-risk patients. Other antiplatelet agents may occasionally be encountered in certain subsets of these patients. It is important to be familiar with some of the other agents.

The currently available antiplatelet drugs fall into three main categories: Thromboxane inhibitors (including aspirin). Aspirin is recommended as a lifelong therapy that should never be interrupted for patients with coronary stents unless the bleeding risk far exceeds the risk for ST. GPIIb/IIIa inhibitors (including tirofiban, eptifibatide, and abciximab). Interventional cardiologists generally use these IV medications in the cardiac catheterization suite during the placement of coronary stents. These drugs can be used to bridge the gap between discontinuation of DAPT and surgery in selected high-risk patients. Tirofiban and eptifibatide have a half-life of 2 hours and bleeding time returns to normal about 4 hours after stopping infusions. However, bleeding risks with these agents are higher than with oral drugs and their effects cannot be reversed with platelet transfusions.

P2Y12 or Adenosine Diphosphate receptor blockers (including clopidogrel, prasugrel, ticlopidine, ticagrelor and cangrelor). Prasugrel (Effient, Daiichi Sankyo/Lilly), a third-generation thienopyridine, was approved by the FDA in 2000. It is more potent than clopidogrel and has a lower rate of drug resistance with a more predictable antiplatelet response. These effects come at the cost fo

Image © Medtronic, Inc.

Antiplatelet Therapy

Figure. Resolute Integrity DES implanted in coronary artery a higher risk for bleeding and greater expense. Ticagrelor (Brilinta, Astra-Zeneca) is an orally active refersible P2Y12 receptor antagonist that was approved by the FDA in 2011. It does not require metabolic activation for its clinical effect. The new short-acting, reversible platelet inhibitor, Cangrelor, is currently being evaluated as a bridging antiplatelet therapy in the perioperative setting.13 High-risk patients with a resistance to aspirin, clopidogrel, or both agents may be placed on these drugs. It is worth mentioning here that heparins possess insignificant antiplatelet effect and are therefore unsuitable as bridge therapy when DAPT is discontinued in the perioperative setting.

Perioperative Considerations Patients with recently placed coronary stents presenting for noncardiac surgery pose a significant challenge to anesthesiologists. It is important to manage these patients with a multidisciplinary team that communicates openly and accepts input from the anesthesiologist, surgeon, and interventional cardiologist.

The perioperative period is particularly risky for patients with coronary stents because of the stress response to surgery, which activates the sympathetic system. It results in the release of inflammatory mediators and stress hormones, and causes platelet activation, vasospasm, and decreased fibrinolysis. Together, these effects lead to the development of a hypercoagulable state in a patient who may already have a disrupted coronary endothelial lining. Pain and anxiety may result in tachycardia and hypertension leading to an increased cardiac demand–supply ratio, which can add additional shear stress to the coronary plaques.

Fearful of the risk for surgical bleeding, well-meaning surgeons or other medical providers may inappropriately advise the patients to discontinue their APT while they are still within the high-risk period after coronary stenting. An abrupt discontinuation of DAPT not only reverses the antiplatelet effect, but also leads to a rebound exaggerated thrombogenic effect. These patients are susceptible to MACE in the perioperative

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27

period, with some studies reporting high mortality rates. Sharma and colleagues evaluated outcomes in patients with BMS undergoing noncardiac surgery.14 They found that patients in whom DAPT was discontinued prematurely had a mortality rate of approximately 85%, compared with 5% for patients in whom therapy was continued. Other studies have found that adverse events are twice as frequent in patients with recently implanted stents (<30 days) than in those in whom stents were inserted more than 90 days before surgery.15 A meta-analysis of more than 50,000 patients with coronary artery disease who were taking aspirin showed that cessation of therapy increased the overall risk for cardiac complications 3-fold. In the subgroup of patients who had coronary stents, the complication rate increased 90-fold.16 Two retrospective studies that evaluated the risk for a perioperative major adverse cardiovascular event in patients presenting for noncardiac surgeries showed that the risk decreases 90 days after a PCI in patients who receive a BMS but remains high even after 1 year in patients who receive a DES.17,18 Successful management of DAPT must evaluate the patient’s risk for bleeding against that for ST. It is generally agreed that during the vulnerable period, the risk for ST in patients with recent PCIs far outweighs that for surgical bleeding. Ideally, DAPT should be continued throughout the perioperative period. If clopidogrel must be discontinued, all efforts should be made to continue aspirin. DAPT should be reinstituted as soon as possible after surgery if it is held for the procedure. The 4-quadrant approach suggested by Metzler et al can be used, with the risk for thrombosis plotted against the risk for bleeding.19 The subset of patients who fall into the quadrant with a high risk for bleeding and ST may benefit from extra caution. Metzler and colleagues suggest that DAPT should be stopped in this subset with the institution of a pharmacologic bridge therapy. Procedures with a high risk for bleeding include intracranial, intramedullary spinal, prostate, middle ear, ophthalmologic, and aortic surgeries.

Patients who remain on APT intraoperatively may experience excessive bleeding. Adequate preparation with IV access and the availability of blood must be planned beforehand. If a platelet transfusion is necessary, it can be safely performed approximately 4 hours after the discontinuation of clopidogrel. The short halflife of clopidogrel and its metabolites will not interfere with the function of transfused platelets.

Optimal intraoperative management of these patients requires tight hemodynamic control to balance the cardiac demand–supply ratio and minimize the shear stress on coronary arteries. When considering regional or neuraxial anesthesia in patients with coronary stents, a risk– benefit analysis must be carefully undertaken, keeping in mind that the patient may need an emergency PCI and additional APT. As with high-risk cardiac patients, the anesthesiologist must remain vigilant for signs of cardiac ischemia and ST. Surgical procedures in patients with coronary

28

A N E ST H E S I O LO GY N E WS .CO M

stents should be performed at institutions with aroundthe-clock availability of interventional cardiology services. Intraoperative ST, a true medical emergency, may present as hemodynamic instability with dysrhythmias and electrocardiographic changes. The current treatment for ST segment elevation MI is acute reperfusion therapy with fibrinolytic agents depending on the risk for bleeding or an urgent PCI (within 90 minutes). In the setting of ST, it is imperative to immediately reperfuse the myocardium to avert a transmural MI. Thrombolytic therapy may be prohibitive in the perioperative period because of the risk for bleeding. PCI therefore is the definitive treatment in this setting requiring emergent action.

Conclusion Current guidelines recommend postponing elective surgery for 2 to 4 weeks of DAPT after balloon angioplasty, 4 to 6 weeks after implantation of a BMS, and 1 year after implantation of a DES. These periods may be extended in high-risk patients or for unapproved use of stents, such as multiple overlapping stents in bifurcating vessels. It is generally accepted that aspirin therapy should be continued indefinitely in patients with PCI, particularly in the perioperative period. Whenever possible, APT should be continued for urgent surgeries that must be performed within the high-risk period. If DAPT is stopped for urgent procedures, clinicians should either bridge with a short-acting antiplatelet agent and/ or restart the DAPT as soon as possible after surgery.

The anesthesiologist, as a perioperative physician, can play a pivotal role in ensuring patient safety. Vigilant care and rapid triage to the interventional cardiology suite in case of MI can prevent catastrophic outcomes.

Early perioperative identification and use of a multidisciplinary team approach, along with well-publicized institutional policies and management guidelines, ensure patient safety.

References 1.

Grüntzig AR, et al. N Engl J Med. 1979;301(2):61-68.

2.

Go AS, et al. Circulation. 2013;127(1):e6-e245.

3.

Joner M, et al. J Am Coll Cardiol. 2006;48(1):193-202.

4. Aoki J, et al. J Am Coll Cardiol. 2005;45(10):1574-1579.

5.

Lee YP, et al. EuroIntervention. 2010;5(6):698-702.

6. Garg S, et al. EuroIntervention. 2010;6(2):233-239.

7.

Diletti R, et al. Am Heart J. 2012;164(5):654-663.

8. Fleisher LA, et al. Anesth Analg. 2008;106(3):685-712.

9. Practice alert for the perioperative management of patients with coronary artery stents: a report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology.

2009;110(1):22–23.

10. Levine GN, et al. Circulation. 2011;124(23):2574-2609.

11. Cutlip DE, et al. Circulation. 2007;115(17):2344-2351.

12. Farb AL, Boam AB. N Engl J Med. 2007;356(10):984-987.

13. Angiolillo DJ, et al. JAMA. 2012;307(3):265-274.

14. Sharma AK, et al. Catheter Cardiovasc Interv. 2004;63(2):141-145.

15. Vincenzi MN, et al. Br J Anaesth. 2006;96(6):686-693.

16. Eberli D, et al. J Urol. 2010;183(6):2128-2136.

17. Nuttall GA, et al. Anesthesiology. 2008;109(4):588-595.

18. Rabbitts JA, et al. Anesthesiology. 2008;109(4):596-604.

19. Metzler H, et al. Curr Opin Anesthesiol. 2008;21(1):55-59.

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Perioperative Fluids: An Evidence-Based Review

ELIZABETH A. M. FROST, MD Professor of Anesthesia Icahn School of Medicine at Mount Sinai New York, New York The author reports no relevant financial conflicts of interest.

M

any questions have arisen and much controversy has emerged

regarding how much fluid

should be given perioperatively, which fluids should be given, when they should be given, and whether outcomes can be influenced. It’s been called the “Great Fluid Debate.” In fact, one might ask

Background

whether the anesthesiologist can even make a difference in the long run. Several goals of fluid administration have been identified: Tissue perfusion should be optimized; and heart rate, stroke volume, hemoglobin, and oxygen saturation should be appropriately manipulated.

But just how to achieve these end points, and whether they can be done by fluid administration, remains unclear. Our current standard therapy—cannulate a vein, give fluids to maintain blood pressure, and make up for supposed losses—has been challenged for almost a century. Canon noted that fluids administered before operative control of an injury were ineffective,1 an observation emphasized by Bickell and others some 70 years later.2,3 Nevertheless, standard U.S. Army protocols called for massive crystalloid resuscitation in the arena of war—especially in Vietnam—to preserve the kidneys. Thus, the Da Nang lung, or adult respiratory distress syndrome, was born.4

Galen was among the first to appreciate the circulation of the blood in the second century A.D., recognizing a difference between venous (dark) and arterial (bright) blood.5 He posited 2 circulations, venous through the liver and arterial via the heart. It was not until 1628 when the role of the heart as a pump was described by Harvey in de Motu Cordis.6 Sir Christopher Wren along with Robert Boyle are credited with being the first to propose and demonstrate IV administration of medications (wine and opium) into dogs, using an animal bladder and quills.7 O’Shaughnessy, an Irish physician who trained in Edinburgh and then moved to London, examined the blood in a healthy state and in cases of cholera,

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noting a deficiency in salt in the latter samples.8 He recommended the injection of aqueous fluid into the veins.

Building on these observations, Thomas Latta, during the cholera epidemic of Scotland in 1831-1832, decided to “throw the fluid immediately into the circulation.”9 He described inserting a tube into a basilica vein and injecting ounce after ounce of a solution containing “two to three drachms of muriate of soda and two scruples of the subcarbonate of soda in six pints of water.”9 He used a pump that had been patented in 1830 by Reid to remove stomach contents. Francis Rynd, another Irish physician, is credited with the introduction of the hypodermic syringe during the 1840s.10 Some 10 years later, Alexander Wood produced the first hypodermic syringe that had a hollow needle attached.11 IV infusion of anesthetic agents, first chloral hydrate and later hedonal, became popular during the latter part of the 19th century.12 For a brief period, both ether and chloroform were administered in saline solutions.12 By the middle of the 20th century, short-acting agents, especially pentothal and amytal, were used for minor and major surgeries, administered as infusions, and often combined with local infiltration and nitrous oxide.12 A more routine use of continuous fluid infusion during surgery was introduced by Hirshfeld, Hyman, and Wang in 1931, but they also noted that too rapid administration could cause “speed shock.”13 Nevertheless, by the mid1950s, various solutions were available and were administered using glass bottles and red rubber resterilizable infusion sets. In Europe, however, many centers continued the practice of securing a vein preoperatively with a metal needle, the end of which was then closed with a moveable external rubber stopper. Induction agents were given, but fluids only if deemed necessary.

The Third Space?

Traditionally, we have been taught that there are 3 spaces—intravascular, extravascular, and a space that appears during surgery or trauma. The origin of this third space came about some 60 years ago in Texas.14 Using 2 groups of patients, 5 undergoing minor surgery (group 1) and 13 having major procedures such as cholecystectomy, gastrectomy, or colectomy (group 2), Shires and colleagues measured plasma volume, red blood cell mass, and extracellular volumes on 2 occasions using tagged substances. No IV fluids were given.

They found a decrease in functional extracellular fluid in group 2 and thus determined that fluid (up to 28% of the extracellular water) was redistributed due to the surgery and needed to be replaced. Two years previously, Moore, a Boston surgeon, had suggested that there was a metabolic response to surgical stress and the release of antidiuretic hormone (ADH) that caused the retention of sodium and water and that, therefore, perioperative fluids should be restricted.15 He also emphasized that the type of anesthesia (in the Texas studies, cyclopropane and ether were used), the complexity of the surgery, the time involved, and other comorbidities should all be taken into consideration. A debate developed in

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the literature, with both sides ultimately calling for moderation in fluid replacement.16 However, the idea of a mysterious third space took hold; protocols were developed to compensate for it and for other supposed intraoperative requirements. The 4:2:1 or 100-50-20 rule was developed and has remained in general practice, despite its lack of relevance to anesthesia today.17 Basically, depending on weight, the rule calls for 4 mL/kg/h for the first 10 kg to be followed by 2 mL/kg/h for the next 10 kg and finally 1 mL/kg/h thereafter; or, in daily replacement, 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, and 20 mL/kg for any weight over that. In other words, a 70-kg patient should receive 110 mL/h replacement, or around 2,500 mL fluid/d. What should be realized is that Holliday’s article was intended for pediatric application and not specifically for intraoperative application. It was based on 3 theories from earlier work: • Surface area can estimate water expenditure.18 • Caloric needs depend on age, weight, activity, and food (a comparison was made between a steer and a rat).19 • Urinary output and insensible losses correspond to age (but only up to age 20 and weight <60 kg, based on the theory that caloric need/kg = 100 – 3× age).20 These papers were founded on even earlier studies, some from as few as 2 patients and using gasometer estimates of body surface area from the 1920s.

The relevance of these rules must be considered in light of present-day practice. They were developed without scientific evidence, much of which was supposition based on unpublished data; the anesthetic and surgical techniques since have changed drastically; the application of the rules was intended for children on a daily basis; and, at the very least, they were meant only as a very rough guide. Nevertheless, we continue to fluid load.

The Case For and Against Fluid Loading Clinicians have presented cases for and against perioperative fluid administration for decades.

FOR Several assumptions are made to explain why fluids should and indeed must be given perioperatively: • The patient is fasted preoperatively and is thus hypovolemic.

• Insensible losses continue during surgery and must be accounted for.

• Fluid shifts to the “third space” must be replaced.

• Blood must be replaced at 3 or 4:1 crystalloid.

• Hypotension following induction is due to vasodilation and the vascular space must be filled.

• Urine output must be taken into consideration and replaced.

• Even if the patient is overloaded, the kidneys will regulate.

• We have always done it that way.

Each of these arguments can be examined and found flawed, resulting in a case for at least a review of this line of thinking.

AGAINST A patient’s preoperative hydration state is largely unknown and the target is unclear. Pulmonary artery wedge pressures and central venous pressures do not indicate volume responsiveness. Preoperative fasting for 8 to 10 hours results in a slight decrease in extravascular fluid. However, intravascular volume is maintained. Putting it in perspective, 1 L crystalloid is the approximate volume of 4 cups of coffee, an amount that rarely has to be consumed before 8 AM to avoid dehydration. Also, the recommendations for fasting guidelines from the American Society of Anesthesiologists now advocate water or clear fluid intake 2 hours preoperatively.21 Bowel preparation, also targeted as a cause of hypovolemia, is undertaken less frequently. The effenescent drugs used today mean that the patient is awake and able to take fluids much sooner. Combinations of antiemetics and better pain control also have hastened the patient’s return to the preoperative state. Hypotension following induction is more likely related to administration of the anesthetic drug or to other comorbidities.

Much surgery today is performed using laparoscopic, robotic, or minimally invasive techniques. Even in the case of open approaches, irrigation is constant. Temperature control and humidification systems further reduce insensible losses. Urinary output is frequently low during periods of stress due to ADH release; giving fluid boluses is more likely to result in fluid overload than in diuresis.

This begs the question: “If the kidneys are already under stress can they compensate, and if so during what time period?” Preexisting renal problems or administration of drugs that hamper kidney function may further delay diuresis, resulting in greater weight gain.

Regarding the argument concerning the third space, we might ask, if it exists, how do we measure it? There are ongoing fluid shifts that may peak around 5 hours, persisting for days.22 Infused fluids may take up to 3 weeks to be excreted. Indeed, the very existence of a third space has been emphatically rejected.23 The rationale of replacement of blood by 3 or 4 times as much crystalloid stems from the fast movement of the latter out of the vascular space, leaving less than one-third to actually replace the blood. This extravasated fluid moves rapidly to dependent and soft tissue areas such as the lungs and gut, with the end result of weight gain.

The argument that “we have always done it this way” may be the most difficult to refute. Generally, a minimum of 20 years is required for proven measures to become universally adopted, or as Boswell remarked in 1770, “That fellow seems to me to possess but one idea, and that is a wrong one.”

Problems With Study Designs

arisen. First, there has been little consensus as to what represents liberal (20 mL/kg/h), standard (5-10 mL/kg/h), or restrictive (2-5 mL/kg/h) replacement. Most studies have not been standardized for reasonable comparison. Study targets also are open to speculation (Table 1).

Many clinicians are unwilling to change “established” protocols. Clear differentiation between major and minor surgery does not exist.

Perhaps the target that has been most closely associated with adverse outcome is that of weight gain.

Lowell found that several parameters were improved with reduced crystalloid infusion (Table 2).22

Table 1. Targets Used Without Standardization Study Targets Weight gain Postoperative nausea and vomiting Pain Tissue oxygenation Postoperative ileus Pneumonia Revision surgery Wound healing Infection Cardiovascular diseases Hospital stay Coagulopathies

Table 2. Outcomes With Low Versus Aggressive Crystalloid Infusion Crystalloid Infusion Low: 4 L

Aggressive: 12 L

Weight gain, %

4.7

32

Postoperative ventilation, d

1.7

6

Vasopressors, d

2.8

26

ARF, %

17

33

Mortality,%

10

100

ARF, acute renal failure

Although it might seem simple to arrive at a formula that could be applied universally, many difficulties have

From reference 22.

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Conflicting data surround the effect of fluid administration on postoperative nausea and vomiting. Liberal fluid administration especially appears to be beneficial for younger women undergoing short gynecologic procedures.23 Time to wound healing has been used as a study target. Oxidative killing by neutrophils is essential to tissue repair. Mild hypothermia reduces tissue oxygenation by a factor of 3. Although supplemental oxygen can increase availability, this effect is not seen in hypoperfused areas that may be edematous from extravasated fluid. In patients receiving liberal fluid replacement, the infection rate and time of hospitalization increased.24-26 Major surgery is not well defined, whether it be by length or complexity of the procedure. Also, the experience and level of training of the surgeon and the identification of the hospital center as a tertiary care center are unknown factors.

Fluids and Body Systems Due to the rapid rate at which crystalloids leave the vascular compartment, effects are seen in most body systems, especially when the fluid balance is markedly positive. Swelling of the face and neck is often marked after hours in the prone position, delaying time to safe extubation.

GASTROINTESTINAL FUNCTION As fluid accumulates in the gut wall, intraabdominal pressure (IAP) increases, especially in obese individuals in whom resting IAP is elevated. This rise in IAP results in impaired pulmonary function and decreased renal perfusion, especially when mean arterial pressure also is decreased. Increased IAP also stimulates the production of ADH, also contributing to oliguria. As fluid overload increases, gut wall edema allows the translocation of endotoxins and/or bacteria, leading eventually to sepsis and multiple organ failure.

Postoperative ileus remains a major problem following abdominal surgery. Several studies have indicated that fluid reduction and limiting positive fluid balance to 1 to 2 L contributes significantly to decreased severity and duration of this debilitating complication and reduces hospital length of stay.27,28

CARDIAC EFFECTS Fluid overload, especially in patients with underlying cardiac disease, may result in congestive heart failure. In 4,059 patients undergoing major noncardiac surgery, cardiac events occurred 3 times more often in those with a positive fluid balance exceeding 3.2 L compared with those with a balance less than 2 L.32 Vretzakis et al studied 192 patients undergoing cardiac surgery. In group 1 (100 patients), fluids were turned off after induction.33 Fluids were unrestricted in group 2 (92 patients). Sixty-two patients in group 1 required blood transfusions compared with 76 in group 2. Also, the total number of units given in group 1 was 113 and in group 2 was 176 (P<0.001). The researchers concluded that hemodilution increased transfusion needs.

RENAL SYSTEM Renal demands increase with fluid overload. The secretion of ADH, aldosterone, and renin after injury or stress decrease water and sodium excretion, delaying excretion of an acute saline load by days or weeks. Historically, fluids have been given to prevent renal failure, although there is no evidence of an association between oliguria and later renal failure. Moreover, oliguria intraoperatively often does not respond to fluid loading, and preloading may not prevent later renal failure.34 Chronic kidney disease often is associated with cardiovascular problems. Fluid and electrolyte balance is deregulated in patients with chronic kidney disease and excess fluid therapy contributes to postoperative morbidity and mortality.35 Diuresis forced through fluid overload does not offer any renoprotection; rather, the opposite. A rationale for fluid replacement involving the endocrine system (renin–angiotensin–aldosterone– vasopressin) may be appropriate with the concept of a zero-fluid balance policy, according to some recent studies.35 Although an older concept advised anesthesiologists to administer large amounts of fluid after kidney transplant to force the new organ to function, recent studies indicate that graft survival was better in patients in whom the mean arterial pressure was greater than 93 mm Hg and less than 2.5 L fluid was infused.36 Extremity reimplantation and flap survival also are improved when less fluids are given.37

PULMONARY EFFECTS Direct correlation had been shown between the development of postoperative acute lung injury (adult respiratory distress syndrome [ARDS]) and liberal fluid administration.29 Fluid balance is best kept at no more than +1.5 L. In a study of patients undergoing vascular surgery, respiratory failure occurred in 10% of those who received more than 6 L of fluid in 24 hours.30 Of 89 patients who had respiratory failure postoperatively, 25 developed ARDS. Intraoperative fluid administration of 20 mL/kg/h was associated with a 3.8 times higher adjusted odds ratio of developing ARDS. The ratio was 2.4 times at 10 to 20 mL compared with patients who received less than 10 mL/kg.31

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POSTOPERATIVE VISUAL LOSS Postoperative visual loss after long back surgery and robotic procedures performed in a steep Trendelenburg position has been linked with a compartment syndrome caused by excessive intraoperative fluid administration.

Guidelines advise combining crystalloids and colloids, giving both in reduced amounts.38

What To Infuse: Blood, Crystalloids, or Colloids?

Blood transfusions are rarely indicated in elective procedures. The American Society of Anesthesiologists noted that blood should rarely be given if hemoglobin

is greater than 10 g and almost always when hemoglobin is less than 6 g.39 As such, it is clear that blood transfusion must be individualized. Rate of loss must be considered, as should hemodynamic status and comorbidities.

The most commonly administered crystalloid is normal saline. However, in a study of nearly 23,000 patients, hyperchloremic metabolic acidosis occurred in 22% of patients and was independently associated with increased morbidity and mortality.40 Mortality at 30 days was 3% versus 1.9% in patients who did not have metabolic acidosis. Hospital lengths of stay increased by almost 1 day.

Hydroxyethyl starch (HES) is available in several preparations (Hespan, B.Braun; Voluven, Hospira; Volulyte, Fresenius Kabi). It is subclassified according to molecular weight and presence of electrolytes. In 2013, the FDA issued a black box warning that HES was not to be used in ICUs.41 A Cochrane review of colloid solutions and crystalloid fluids in 78 trials concluded that resuscitation with colloids did not reduce the risk for death and that HES increased mortality if the liver or kidneys were injured.42 Another Cochrane review examined the effects on kidney function in more than 11,000 patients. HES increased the need for renal replacement therapy43; however, a safe volume of HES was not defined.

The Surviving Sepsis Campaign issued several guidelines regarding management of patients in sepsis.44 Several trials were reviewed—including the VISEP (Efficacy of Volume Substitution and Insulin Therapy in Severe Sepsis), CRYSTMAS (Effects of Voluven on Hemodynamics and Tolerability of Enteral Nutrition in Patients With Severe Sepsis), SAFE (Saline versus Albumin Fluid Evaluation), and CHEST (Crystalloid versus Hydroxyethyl Starch Trial) studies—which did not show any difference in survival between patients administered colloids and saline resuscitation.45 However, the conclusions drawn were that although colloid might increase renal damage in patients with preexisting kidney failure, extra fluid increased mortality and conservative fluid replacement was indicated. Further recommendations included the use of vasopressors (norepinephrine, then epinephrine, then vasopressin) to restore blood pressure rather than fluids and the use of stroke volume to guide therapy.

Phenylephrine, low-dose dopamine, and steroids probably have a limited place in the care of these patients.44 Following these reviews, many hospital pharmacies decided that based on the increased cost of synthetic colloids, they should be banned.

However, a more rational view might be to use both colloids and crystalloids but in reduced amounts. Colloids maintain vascular volume and maintain hemodynamic status better than crystalloids. A study of damage-control resuscitation indicated that mortality increased when greater than 6 L of crystalloids were given and was reduced when 1 L of colloid was used.46 During normovolemic anemia, a third-generation tetrastarch (Voluven) maintained tissue perfusion in an animal model, whereas lung water increased and oxygen saturation decreased with lactated Ringer’s solution.47

GLYCOCALYX The glycocalyx, a very fragile system, coats the vascular endothelium and acts like a filter. Glycocalyx is the main constituent of the vascular barrier with selective protein filtration.48 It can easily be destroyed by surgery, trauma (central cannulation), ischemia/reperfusion, sepsis, inflammatory mediators, hyperglycemia, and acute hypervolemia. As the filter breaks down, destruction causes leukocyte adherence, platelet aggregation, and edema. Maintaining a physiologic concentration of plasma protein, particularly albumin, can prevent glycocalyx damage.

Monitoring Fluid Balance Historically, anesthesiologists have cannulated a vein, connected the cannula to a flow system, and infused fluids hoping that the amount given will compensate for unknown losses and maintain hemodynamic stability. A more accurate means of assessing need and volume responsiveness is based on pulse pressure variation.49 By looking at arterial pressure waveforms and respiratory excursion, stroke volume and cardiac output can be established by algorithm. Several commercial monitors are available, including Vigileo and FloTrac (Edwards Lifesciences) and LiDCO (LiDCO), among others. Fluid monitoring has become less invasive with innovation, such that invasive technologies of the past

Table 3. Comparisons Between Crystalloids and Colloids Crystalloids

Colloids

Distributed in entire extracellular compartment

Expands plasma volume by amount infused

80% leaves vasculature

More expensive

Infused amount correlates to weight gain

Infection and allergenic responses very low

Causes dilutional coagulopathies in large amounts

? coagulopathies in larger amounts

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have been replaced with less invasive and even noninvasive modalities.

Transesophageal echocardiography also is valuable in measuring cardiac output and guiding fluid therapy. Real-time direct visualization of cardiac motion is possible, and allows preemptive maintenance of fluid requirements. Other monitors incorporate sensors on endotracheal tubes, again measuring pulse pressure variation.

For a prompt bedside evaluation, lung ultrasound may assess pulmonary congestion through the evaluation of vertical reverberation artifacts, known as B-lines.

These handheld devices can easily indicate accumulation of extravascular lung water.50 A study of 55 patients in septic shock indicated that extravascular lung water was significantly higher by day 3 in nonsurvivors, as capillary permeability increased with a higher positive fluid balance.51 Although central venous pressure continues to be used as a monitor, it does not indicate circulating blood volume or vascular responsiveness to a fluid challenge.52 It should not be used to make clinical decisions regarding fluid administration.

What To Infuse Crystalloids in moderate amounts should be used to replace urine and insensible losses, the latter usually not more than 0.5 mL/kg/h. Colloids can replace plasma deficits, acute blood loss, and protein-rich fluids. The amount of colloid given should be approximately 1 to 2 L but should not be administered to patients with kidney or liver disease. There is no rationale for substituting 1 L blood loss with 3 to 4 times crystalloid infusion. Blood should be used sparingly.47 Overnight fasting does not deplete the vascular space, and the third space does not exist. The aim is to preserve normovolemia in all body compartments with a fluid balance as close to zero as possible.

Conclusion After decades of research it is clear that current practices of fluid infusion should be reevaluated. No IV infusion should be continued simply because it is a routine. Optimizing the volume infused is the key to ideal postoperative outcome with maximum fluid shifts of no more than 2 to 3 L. The question arises, “Are we ready for the change?”53

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Canon WB. The course of events in secondary wound shock.

JAMA. 1919;73:174-181.

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Bickell WH, Shafton GW, Mattox KL. Intravenous fluid administration and uncontrolled hemorrhage. J Trauma. 1989;29:409.

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Moore FD. Common patterns of water and electrolyte change in injury, surgery and disease. N Engl J Med. 1958;258:277-285, contd.

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Dalton AM. Prehospital intravenous fluid replacement in trauma; an outmoded concept? J R Soc Med. 1995;88:213P-216P.

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Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics. 1957;19:823-832.

4.

Oud L. From DaNang lung to combat trauma-associated acute lung injury—closing the loop. South Med J. 2009;102:567-568.

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Crawford JD, Terry ME, Rourke. GM Simplification of drug dosage calculation by application of the surface area principle.

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Rocca J. Galen on the brain: anatomical knowledge and physiological speculation in the second century AD. Stud Anc Med. 2003;26:1-313.

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Darrow DC, Pratt EL. Fluid therapy; relation to tissue composition and the expenditure of water and electrolyte. JAMA. 1950;143:365-373.

Harvey W. Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus 1628; translated Leake CD, Charles C Thomas, Springfield IL 1928 (original published in Latin, Frankfurt 1628).

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Wallace WM. Quantitative requirements of the infant and child for water and electrolyte under varying conditions. Am J Clin Pathol. 1953;23:1133-1141.

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Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: A Report by the American Society of Anesthesiologists Task Force on Preoperative Fasting. Anesthesiology. 1999;90:896-905.

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MacGillivray N. Dr. Thomas Latta; the father of intravenous infusion therapy. J Infect Prev. 2009;10;s3-s6.

Lowell JA, Schifferdecker C, Driscoll DF, et al. Postoperative fluid overload: not a benign problem. Crit Care Med. 1990;18:728-733.

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Francis Rynd. Inventor of the hypodermic syringe. http://www. irelandcalling.ie/francis-rynd (accessed August 19th 2014)

Doherty M, Buggy DJ. Intraoperative fluids; how much is too much? Br J Anaesth. 2012;109:69-79.

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Yaksh TL, ed. Spinal Drug Delivery. New York: Elsevier, 1999.

Kabon B, Akca O. Taguchi A, et al. Supplemental intravenous crystalloid administration does not reduce the risk of surgical wound infection. Anesth Analg. 2005;101:1546-1553.

12.

Searles PW. Intravenous anesthesia. JAMA. 1942;118:117-119.

25.

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Hirshfeld S, Hyman HT, Wanger JJ. Influence of velocity on the response to intravenous injections. Arch Intern Med. 1931;47:259-287.

Hiltebrand LB, Pestel G, Hager J, et al. Perioperative fluid management; comparison of high, medium and low fluid volume on tissue oxygen pressure in the small bowel and colon.

Eur J Anaesthesiol. 2007;24:927-933.

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Shires T, Williams J, Brown F. Acute changes in extracellular fluids associated with major surgical procedures. Ann Surg.

1961;154:803-810.

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Nisanevich V, Feisenstein I, Almogy G, et al. Effect of intraoperative fluid management on outcome after intrabdominal surgery.

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Chowdhury AH, Lobo DN. Fluids and gastrointestinal function.

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Walsh SR, Tang TY, Faroog N, et al. Perioperative fluid restriction reduces complications after major gastrointestinal surgery.

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40. McCluskey SA, Karkouti K, Wijeysundera D, et al. Hyperchloremia after noncardiac surgery is independently associated with increased morbidity and mortality: a propensity-matched cohort study. Anesth Analg. 2013;117:412-421.

41.

Evans RG, Naidu B. Does a conservative fluid management strategy in the perioperative management of lung resection patients reduce the risk of acute lung injury? Interact Cardiovasc Thorac Surg. 2012:15:498-504.

Zarychanski R, Abou-Setta AM, Turgeon AF, et al. Association of hydroxyethyl starch administration with mortality and acute kidney injury in critically ill patients requiring volume resuscitation: a systematic review and meta-analysis. JAMA. 2013;309:678-688.

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Bajwa SS, Kulshrestha A. Diagnosis, prevention and management of postoperative pulmonary edema. Ann Med Health Sci Res. 2012;2:180-185.

Perel P, Roberts I, Ker K. Colloids versus crystalloids for fluid resuscitation in critically ill patients. Cochrane Database Syst Rev. 2013;2:CD000567.

43.

Mutter TC, Ruth CA, Dart AB. Hydroxyethyl starch (HES) versus other fluid therapies: effects on kidney function. Cochrane Database Syst Rev. 2013;7:CD007594.

Hughes CG, Weavind L, Banerjee A, et al. Intraoperative risk factors for acute respiratory distress syndrome in critically ill patients. Anesth Analg. 2010;111:464-467.

44. Dellinger RP, Levy MM, Rhodes A, et al. Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012. Crit Care Med. 2013;41:580-637.

Polanczyk CA, Rohde LE, Goldman L, et al. Right heart catheterization and cardiac complications in patients undergoing non cardiac surgery: an observational study. JAMA. 2001;286:309-314.

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Vretzakis G, Kleitsaki A, Stamoulis K, et al. Intra-operative intravenous fluid restriction reduces perioperative red blood cell transfusion in elective cardiac surgery, especially in transfusionprone patients: a prospective, randomized controlled trial.

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Alpert RA, Roizen MF, Hamilton WK, et al. Intraoperative urinary output does not predict postoperative renal function in patients undergoing abdominal aortic revascularization. Surgery.

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Sadaka F, Juarez M, Naydenov S, et al. Fluid Resuscitation in Septic Shock: The Effect of Increasing Fluid Balance on Mortality.

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Guidry C, Gleeson E, Simms ER, et al. Initial assessment on the impact of crystalloids versus colloids during damage control resuscitation. J Surg Res. 2013;185:294-299.

47.

Pape A, Kutschker S, Kertscho H, et al. The choice of the intravenous fluid influences the tolerance of acute normovolemic anemia in anesthetized domestic pigs. Crit Care. 2012;16:R69.

48.

Alphonsus CS, Rodseth RN. The endothelial glycocalyx: a review of the vascular barrier. Anaesthesia. 2014;69:777-784.

35.

Iijima T. Perioperative fluid therapy for surgical patients with chronic kidney disease. Masui. 2013;62:1304-1312.

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Campos L, Parada B, Furriel F, et al. Do intraoperative hemodynamic factors of the recipient influence renal graft function?

Transplant Proc. 2012;44:1800-1803.

Auler, JO Jr., Galas F, Hajjar L, et al. Online monitoring of pulse pressure variation to guide fluid therapy after cardiac surgery.

Anesth Analg. 2008;106:1201-1206.

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Cardinale L, Priola AM, Moretti F, et al. Effectiveness of chest radiography, lung ultrasound and thoracic computed tomography in the diagnosis of congestive heart failure. World J Radiol.

2014;6:230-237.

51.

Mallat J, Pepy F, Lemyze MJ, et al. Extravascular lung water indexed or not to predicted body weight is a predictor of mortality in septic shock patients. J Crit Care. 2012; 27:376-383.

52.

Marik PE. Iatrogenic salt water drowning and the hazards of a high central venous pressure. Ann Intensive Care. 2014;4:21.

53.

Della Rocca G, Vetrugno L, Tripi G, et al. Liberal or restricted fluid administration: are we ready for a proposal of a restricted intraoperative approach? BMC Anesthesiol. 2014;14:62.

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Brinkman JN, Derks LH, Klimek M, et al. Perioperative fluid management and use of vasoactive and antithrombotic agents in free flap surgery: a literature review and clinical recommendations.

J Reconstr Microsurg. 2013;29:357-366.

Lee LA. Perioperative visual loss and anesthetic management.

Curr Opin Anaesthesiol. 2013;26:375-381.

Practice Guidelines for Perioperative Blood Transfusion and Adjuvant Therapies: An Updated Report by the American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies. Anesthesiology. 2006; 105:198-208.

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Practical Considerations in Urine Drug Screening: Compliance and Regulations for Office-Based Testing JEFF GUDIN, MD Director, Pain and Palliative Care Englewood Hospital and Medical Center Englewood, New Jersey Dr. Gudin has relationships with industry, including as a scientific advisor to Alere Toxicology.

â?&#x2122;

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onitoring for complianc ce and aberrant

behaviors plays an esse ential role in long-

term opioid therapy for patients with

chronic pain. Urine drug testing (UDT) is considered one of the mainstays of adherence monitoring, and, in conjunction with prescription monitoring programs and other screening tools, promotes the safe and effective use of these potent medications.1

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Table 1. Comparison of Laboratory Tests and Point-of-Care Testing2-5 Criterion

Laboratory Tests

Point-of-Care Testing

Time to results

Initial results within hours; confirmatory tests within days

Minutes

Ease of use

Requires complex equipment

Relatively simple

Training

Requires trained technicians or technologists

Minimal training received

Breadth of tests

Wide range of test menus

Limited test menu

Interpretation

Objective quantitative results; variations in laboratory Subjective results, not quantitative; cutoff concentrations may influence interpretation requires interpretation

The literature is replete with references on the biological and technical aspects of UDT in pain management, but rarely focuses on the associated regulatory or compliance requirements associated with office-based or point-of-care testing (POCT). The purpose of this review is to introduce clinicians to the basics of these requirements and offer practical considerations for implementing policies and procedures in the office setting.

Drug testing usually but not always involves a 2-step process: an initial screen that identifies potentially or presumptively positive and negative specimens, followed by a confirmatory assay. Initial screening tests qualitatively indicate the presence or absence of a substance or its metabolite, but also can indicate the presence of a crossreactive, chemically similar substance (ie, false positive result). The screening test can be done in a laboratory or at the point of care, and usually employs an antigen-antibody immunoassay technique (Table 1).2-5 Confirmative assays are recommended by many POCT companies, and typically utilize liquid chromatography or gas chromatography mass spectrometry. It is beyond the scope of this review to discuss windows of detection of various drugs, specimen validity, cutoff concentrations, or crossreactive substances (see Lynn Webster’s piece in Pain Medicine News on the subject, among others).5

Federal Oversight The use of POCT is covered by 2 federal regulations.

The Medical Devices Act requires that all in vitro medical diagnostic devices be evaluated and cleared for use by the FDA for commercial distribution before use with patients. The FDA has cleared several point-of-care devices for testing drugs of abuse. The FDA Center for Devices and Radiological Health provides information on the clearance of testing devices.6 All facilities in the United States that perform laboratory testing on human specimens for health assessment or the diagnosis, prevention, or treatment of disease are regulated under the Clinical Laboratory Improvement Amendments of 1988 (CLIA).7 CLIA regulates the use of POCTs and sets forth standards to certify laboratories to perform those tests. However, a test may be waived from CLIA regulatory oversight if it meets

certain requirements. These tests include those cleared by the FDA for home use, and other simple, low-risk tests categorized as waived under CLIA (CLIA waived [CW]). Although CLIA requires that waived tests must have a low risk for erroneous results, this does not mean that waived tests are completely error-proof. Errors can occur anywhere in the testing process, particularly when the manufacturer’s instructions are not followed and when testing personnel are not familiar with all aspects of the test system.

In 2005, the Centers for Disease Control and Prevention’s Division of Laboratory Science and Standards (DLSS; previously the Division of Laboratory Systems), published Morbidity and Mortality Weekly Report Recommendations and Reports on “Good Laboratory Practices for Waived Testing Sites.”8 The recommendations are intended as a resource for physicians, nurses, and others who perform waived tests in sites holding a CLIA Certificate of Waiver. These were published to promote quality testing, reduce testing errors, and enhance patient safety. It also included steps to be taken as a facility begins offering waived testing or adds a new waived test, and addressed implementing policies and procedures and personnel training. Table 2 includes recommended practices from that document.8 A valid CLIA certificate is required for Medicare reimbursement and each site must obtain a CLIA waiver before testing patient specimens. Each testing site should identify at least one site director responsible for testing oversight and decision making. Ideally, the person signing the CW application is responsible for management of the testing operations. To apply for a CLIA certificate, CMS (Centers for Medicare & Medicaid Services) Form 1169 must be completed and sent to the state agency in which the testing site is located. This form asks for specific information, including the type of testing site (laboratory type), hours of operation, estimated total annual volume of waived testing, and the number of persons involved in performing waived testing. The facility owner or director must sign the form.

CLIA requirements that apply to testing sites operating under a waiver include renewal every 2 years, performance of only waived tests, following the instructions

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Table 2. Factors To Consider Before Offering Waived Testing8

Table 3. CLIA Requirements for Laboratories Performing Waived Tests Only

Identify who will be responsible and accountable for testing oversight at the CLIA-waived site.

Enroll in the CLIA program.

Ensure that person has the appropriate training for making decisions on testing.

Follow manufacturer’s instructions for waived tests.

Understand the federal, state, and local regulations that apply to testing, and ensure that the site is adequately prepared to comply with all regulatory requirements.

Observe storage and handling requirements for the test system components.

Know the safety considerations for individuals conducting testing and those being tested.

Recognize the physical and environmental requirements for the testing space.

Consider whether personnel are sufficient to conduct testing, how they will be trained, and how testing competency will be maintained.

Understand what written documentation will be needed, and how test records will be maintained.

C CLIA, , Clinical C ca Laboratory abo ato y Improvement p ove e t Amendments e d e ts

in the most current manufacturer’s product insert without modification, and permitting announced or unannounced on-site inspections by CMS representatives (Table 3).

Adhere to expiration date of the test system and reagents.

Perform quality control, function checks, and equipment maintenance.

Train personnel.

Report patient’s test result in units described in the package insert.

Send specimens for confirmatory tests when required by the manufacturer.

Ensure limitations are observed.

Do not make any modifications to the testing device.

Permit inspections by CMS agent if required.

CLIA, Clinical Laboratory Improvement Amendments; C S,, Ce CMS Centers te s for o Medicare ed ca e & Medicaid ed ca d Se Services v ces

Best Practices and Preparation Point-of-care testing should be performed in a separate, designated area where adequate space and lighting to safely conduct testing and maintain patient privacy is available. Additionally, some tests have specific environmental requirements (eg, humidity and temperature), as described in the manufacturer’s product insert, that need to be met to ensure reliable test results. Additional safety practices for performing testing are recommended, such as prohibiting eating, drinking, or applying makeup in areas where specimens are collected; prohibiting storage of food in refrigerators where testing supplies or specimens are stored; providing hand-washing facilities or antiseptic hand-washing solutions; and posting safety information for employees and patients.

Personnel competency and turnover are important factors affecting the quality and reliability of waived testing results. Personnel issues to consider include sufficient skills and time to reliably perform testing in addition to staff’s other duties. As many POCT results are based on color end points, staff should be evaluated for color-blindness, as this can limit their ability to appropriately interpret results. The CW site director should ensure that testing personnel receive adequate training and are competent to perform the procedures for which they are responsible. Training checklists are helpful to ensure that the training process is comprehensive

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and documented. To ensure testing procedures are performed consistently and accurately, periodic evaluation of competency is recommended, with retraining provided as needed.

It is good practice to develop written policies and procedures for waived testing so that responsibilities and testing instructions are clearly described for the testing personnel. These should be in easy-to-understand language and are usually derived from the CLIA requirements as well as the manufacturer’s instructions.

The manufacturers instructions for POCT devices usually include details on patient preparation and specimen collection that highlight key steps in the procedure (eg, test incubation time), test limitations, control procedures, established reference intervals and critical values for the test, how to record and report results, and how to handle critical values.

Preparation before performing testing is critical for producing quality results. Paying attention to test orders, properly identifying and preparing the patient, collecting a good-quality specimen, and setting up the POCT device and testing area all contribute to reliable test results. Sites that are CW should routinely confirm that the order for the test is written in the medical record and the patient is identified before collecting the specimen.

Specimen Collection The person collecting the patient specimen or giving the collection instructions should have a thorough understanding of the specimen type or matrix (urine, saliva, etc), as well as proper collection and handling methods, to assure a quality specimen. Directions for collection, handling, and storage are included in the product insert and must be followed exactly. Testing personnel should perform hand hygiene between each patient. To prevent errors, specimens should always be labeled with pertinent information (eg, unique patient name or other unique identifier). Depending on workflow, specimen labeling might include date and time of collection, and also should identify the collector. For waived tests in which the specimen is applied directly to the test device, the test strip, cassette, or other device should be labeled with the patient identification before the specimen is collected. It is also important that personnel bide by expiration dates and discard expired reagents and test kits as soon as expiration dates elapse.

Performing regular quality control testing provides assurance that the test performs as expected and alerts the user when problems occur. It can detect problems that might arise because of operator error, reagent or test kit deterioration, instrument malfunction, or improper environmental conditions. Office policies and procedures should describe the type of controls to be used, how and how often to perform quality control, and actions to be taken when quality control results are unacceptable. At a minimum, external controls should be tested with each new shipment, new lot number and by each new operator before conducting testing. Controls should be tested either prior to or concurrent with patient specimens by the same personnel who routinely perform patient testing.

Documentation and monitoring of control testing results provide an indication that the operator properly performed the test and that the test system performed as expected. Records of control results should be periodically reviewed to detect shifts or changes in performance over time (Table 4).4 Attention should be paid to the timing for waived tests, particularly unitized test devices that must be read during specific time intervals. Incorrect timing of these types of tests can result in erroneous test results.

Insufficient timing can lead to false-negative or invalid results because the specimen might not react completely with test-system reagents. Time intervals longer than those specified in the product insert can result in false-positive, false-negative, or invalid results because of exaggerated color development, fading of reaction products, or migration beyond a visible range. Therefore, it is important to have a system established to read results during the correct timeframe, especially when conducting multiple tests at a time. Suggestions for ways to ensure correct timing of tests include using timers that beep until turned off, using timers that can easily be worn or attached to clothing, using multiple

Table 4. What To Document for POC Drug Testing4 Written procedures for performing POC tests Inventory (lot numbers and expiration dates) Documentation of staff training and (re)assessment Quality assurance test results Documentation of problems and problem resolution plan Copies of laboratory test orders and results POC, point of care

timers when performing more than one test at a time, and maintaining extra timers and batteries.

Test Results When the test is complete, interpret the results according to instructions in the product insert. Test results are either quantitative or qualitative.

Quantitative tests provide numerical results generated by the test device or instrument. Numerical results are values corresponding to the concentration of the specific substance being measured. The value includes specific measurement units (eg, a glucose result of 100 mg/dL). No interpretation is necessary to read the result.

Qualitative tests detect whether a particular substance or drug is present or absent. Results are interpreted as positive/reactive, negative/nonreactive, or invalid. Invalid results might indicate a problem with the specimen or the test system. Diagrams, color photographs, and color comparison charts often are part of the product insert, are quick references, and serve as guides for interpretation.

Results can be recorded directly into a patientâ&#x20AC;&#x2122;s chart, in logbooks, or on a separate report form.

Records or logs of test results should have enough detail so the test site can retrieve information. Quantitative results should be recorded using the units of measurement of the test system. Qualitative test results should be recorded using interpretive words or abbreviations such as positive, negative, reactive (R), or nonreactive (NR) instead of symbols like plus and minus (+, â&#x20AC;&#x201C;). This will help avoid clerical errors because a negative sign can easily be changed to a positive sign. If a test result is not acceptable or requires repeat testing (eg, out of range or invalid), record the initial result, noting it was unacceptable, take steps necessary to resolve the problem, retest, and record the correct result. Good laboratory practices include recording what happens, whether acceptable or not, and what is done to correct problems encountered during testing.

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A confirmatory test could be a different waived test (performed at the testing site or another CW site), or a nonwaived test performed by a CLIA-certified referral laboratory.

If a discrepancy is identified between the patient’s test results and the clinical information or if the results are invalid or otherwise compromised, testing should be repeated. Results should not be reported until the conflict is resolved. Testing personnel should follow the steps in the product insert to resolve problems with test results. Each site should have documentation of quantitative test measuring ranges and a procedure for handling test results that are beyond the reportable ranges (either low or high). In the pain management setting, CLIA waived urine drug samples are sent to an outside laboratory for highly sensitive and specific quantitative testing, such as liquid or gas chromatography with mass spectrometry. Most often, these labs have toxicologists onsite to assist with interpretation of test results when necessary.

After the completion of the test, results must be documented and reported. Waived testing sites, such as point-of-care sites or physicians’ offices, might accurately and legibly record results directly in the patient’s record as a matter of practice. If results are not recorded directly in a patient’s chart, they should be recorded in a written report format that includes all information needed to correctly identify and interpret the results. Some practitioners photograph or photocopy the waived testing device to document the results.

The CW site should have written policies to ensure that confirmatory and supplemental testing is performed when needed (ie, referral to an outside lab).

For each waived test that requires additional testing, the CW site should document the processes and procedures of confirmatory testing. When a CW site collects specimens for testing, procedures should include the steps shown in Table 5.

Table 5. Documentation of UDT Test orders (written order in the medical record) Documentation of medical necessity for each test Written procedures specific to the test—provided by the product inserts Lot numbers, dates used, and expiration dates of test systems Test results, including any confirmatory or supplemental testing Quality control testing results and corrective action taken if control results are unacceptable Personnel training and competency assessment UDT, urine drug testing

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Clinicians who participate in Medicare and Medicaid need to be familiar with coverage and reimbursement policies regarding therapeutic drug monitoring. To ensure that only medically appropriate tests are ordered, practitioners need to specify the need for each test on a requisition form with either a Current Procedural Terminology code or Healthcare Common Procedure Coding System code. Proper billing for drug screening occurs once per patient. This rule applies regardless of the complexity and number of drug tests performed. For example, a clinician cannot charge 5 times for a 5-panel urine drug test and 11 times for an 11-panel test conducted on a single patient sample. In these cases, CMS can only reimburse the national limit amount, which would not distinguish between a 5-panel and an 11-panel test.9 Also, when building a customized test panel with a laboratory, the clinician should order only those tests deemed medically necessary and not use requisition “templates” that promote overutilization with testing for dozens of unnecessary drugs (“blanket” drug testing).9

Compliance A well-established compliance program can help optimize proper payment of claims, avoid conflicts with self-referral or anti-kickback statutes, minimize billing mistakes, and reduce chances of an audit by the Office of Inspector General or the Health Care Financing Administration.10 Clinicians may wish to complete an office compliance checklist for drug testing to document the medical necessity for the test and ensure that regulations are met.

HIPAA HIPAA established federal privacy standards to protect patients’ medical records and other health information provided to health plans, doctors, hospitals, and other health care providers. Under HIPAA, CW sites are required to establish policies and procedures to protect the confidentiality of health information about their patients, including patient identification, test results, and all records of testing. These medical records and other individually identifiable health information must be protected, whether on paper, in computers, or communicated orally.

Practitioners should consult with their state medical or substance abuse treatment authorities to ascertain the HIPAA requirements and regulations in their state.

Legally Mandated Testing Office drug screening is covered by different regulations than federally mandated testing. The Omnibus Transportation Employee Testing Act of 1991 requires drug and alcohol testing of safety-sensitive transportation employees in aviation, trucking, railroads, mass transit, pipelines, and other transportation industries.

DOT publishes rules on who must conduct drug and alcohol tests, how to conduct those tests, and what procedures to use when testing. Encompassed in 49 Code of Federal Regulations (CFR) Part 40, the Office

of Drug & Alcohol Policy & Compliance (ODAPC) publishes, implements, and provides authoritative interpretations of these rules. A laboratory located in the U.S. is only permitted to participate in DOT drug testing if it is certified by HHS under the National Laboratory Certification Program (NLCP).

Legally mandated drug testing requires the expertise of a Certified Medical Review Officer (CMRO). The CMRO is a physician who is responsible for receiving, reviewing, and evaluating results generated by employers’ drug testing programs. The CMRO is also responsible for the accuracy and integrity of the drug testing process by determining whether there is a legitimate explanation for unexpected test results and protecting the confidentiality of the drug testing information.

When performing tests that are not legally mandated, physicians should be familiar with the specific drug screening statutes and regulations in their own state. State regulations might address chain-of-custody requirements, patient privacy, which specimens may be screened, and how results may be used or shared.11

Conclusion Opioid analgesics remain a necessary option for patients with chronic pain. The risks associated with the use of these medications can be in part mitigated with effective UDT strategies. Most clinicians and office staff are not familiar with the regulatory requirements that include: obtaining a CLIA waiver; developing written policies and procedures for testing; conducting ongoing staff training; establishing quality control procedures; developing and implementing testing protocols; adhering to guidelines for specimen collection; effectively using POCT and confirmatory testing; establishing confidentiality safeguards; establishing recordkeeping procedures; preparing storage sites; and arranging for pickup and transportation of samples.

It is a daunting challenge, but having a strong understanding of all regulatory requirements necessary for office-based or POCT ultimately will allow pain physicians to maintain compliance while they manage their chronic pain patients taking opioid medications.

References 1.

Christo P, Manchikanti L. Urine drug testing in chronic pain. Pain Physician. 2011;14(2):123-143.

2. Manchikanti L, Malla Y, Wargo BW, Cash KA, Pampati V, Damron KS, McManus CD, Brandon DE Protocol for accuracy of point of care (POC) or in-office urine drug testing (immunoassay) in chronic pain patients: a prospective analysis of immunoassay and liquid chromatography tandem mass spectometry (LC/MS/MS).

Pain Physician.. 2010 Jan-Feb;13(1):E1-E22.

3. Gudin JA, Mogali S, Jones JD, Comer SD. Risks, management, and monitoring of combination opioid, benzodiazepines, and/or alcohol use. Pain Physician. . 2013 Jul;125(4):115-30. doi: 10.3810/ pgm.2013.07.2684.

4. Gudin JA1, Mogali S, Jones JD, Comer SD. Owen GT, Burton AW, Schade CM, Passik S. Urine drug testing: current recommendations and best practices. Pain Physician. 2012;15(3 suppl):ES119-133.

5. Webster L. The role of urine drug testing in chronic pain management: 2013 update. Pain Medicine News. 2013;11(10):45-50.

6. US Food and Drug Administration. Device review process. http:// www.fda.gov/aboutfda/transparency/basics/ucm193731.htm.

Accessed May 12, 2014.

7. Lilley RJ. Understanding CLIA ’88. Pa Med. 1992;95(5)24-25.

8. Centers for Disease Control. Good laboratory practices for waived testing sites. Survey findings from testing sites holding a certificate of waiver under the Clinical Laboratory Improvement Amendments of 1988 and recommendations for promoting quality testing.

MMWR. November 11, 2005 / 54(RR13);1-25. http://www.cdc.gov/ mmwr/preview/mmwrhtml/rr5413a1.htm. Accessed May 13, 2014.

9. Centers for Medicare & Medicaid Services. How to apply for a CLIA certificate, including international laboratories. http://www.cms. gov/Regulations-and-Guidance/Legislation/CLIA/How_to_Apply_ for_a_CLIA_Certificate_International_Laboratories.html. Accessed May 13, 2014.

10. Owen GT, Burton AW, Schade CM, Passik S. Urine drug testing: current recommendations and best practices. Pain Physician. 2012 Jul;15(3 Suppl):ES119-ES!33.

11. .Standridge J, Adams S, Zotos A. Urine drug screening: a valuable office procedure. Am Fam Physician. 2010;81(5):635-640.

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Current Concepts In the Management Of the Difficult Airway Volume 11, Number 2

CARIN A. HAGBERG, MD Joseph C. Gabel Professor and Chair Department of Anesthesiology The University of Texas Medical School at Houston Director of Advanced Airway Management Memorial Hermann Hospitalâ&#x20AC;&#x201C;Texas Medical Center Houston, Texas Executive Director 2009-Present, Society for Airway Management Dr. Hagberg has received grant support from Ambu, Cadence Pharmaceuticals, and Karl Storz Endoscopy, and is also an unpaid consultant for Ambu.

M

anagement of the difficult airway remains one of the most relevant and challenging tasks for anesthesia care providers. This review focuses on several of the alternative airway management

devices/techniques and their clinical applications, with particular emphasis on the difficult or failed airway. It includes descriptions of many new airway devices, several of which have been included in the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm (Figure).

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place an ET through intubating supraglottic ventilatory devices for visualization of ET placement through the SGA (Table 2).

RIGID/VIDEO LARYNGOSCOPES

Figure.

The ASA Difficult Airway Algorithm.

(Anesthesiology y 2013;118[2]:251-270) The algorithm can be viewed at: www.asahq.org/publicationsAndServices/practiceparam.htm

Video-assisted techniques have become pervasive in various surgical disciplines, as well as in anesthesiology. As more video laryngoscopes are introduced into clinical practice, and as airway managers become more skillful with the technique of video-assisted laryngoscopy, it could well become standard procedure for patients with known or suspected difficult airways.

It also may become the standard for routine intubations as the equipment and usersâ&#x20AC;&#x2122; skills improve and the cost of the devices decreases, with the potential for important savings in time and decreased morbidity in patients. It is beyond the scope of this review to discuss all of the laryngoscopes that have been manufactured; thus, only some of the most recently developed blades will be described (Table 3).

INDIRECT RIGID FIBER-OPTIC LARYNGOSCOPES

A common factor preventing successful tracheal intubation is the inability to visualize the vocal cords during the performance of direct laryngoscopy. Many devices and techniques are now available to circumvent the problems typically encountered with a difficult airway using conventional direct laryngoscopy.

These laryngoscopes were designed to facilitate tracheal intubation in the same population that would be considered for flexible fiber-optic bronchoscopy, such as patients with limited mouth opening or neck movement. Relative to the flexible fiber-optic bronchoscopes (FOBs), they are more rugged in design, control soft tissue better, allow for better management of secretions, are more portable (with the exception of the new portable FOBs), and are not as costly. Intubation can be performed via the nasal or oral route and can be accomplished in awake or anesthetized patients (Table 4).

ENDOTRACHEAL TUBE GUIDES

SUPRAGLOTTIC VENTILATORY DEVICES

Several endotracheal tube (ET) guides have been used to aid in intubation or extubation, including both reusable/disposable and solid/hollow introducers, stylets, and tube exchangers (Table 1).

The Laryngeal Mask Airway (LMA, LMA North America, a Teleflex Company) is the single most important development in airway devices in the past 25 years. Since its introduction into clinical practice, it has been used in more than 200 million patients worldwide with no reported deaths. Other supraglottic ventilatory devices are available for routine or rescue situations. The most recently developed supraglottic ventilatory devices have a gastric channel or are intended to be used as a conduit for fiber-optic guided intubation (Table 5).

Alternative Airway Devices

LIGHTED STYLETS In the past decade, many lighted stylets have been developed, including light wands, which rely on transillumination of the tissues of the anterior neck to demonstrate the location of the tip of the ETâ&#x20AC;&#x201D;a blind technique, unless combined with direct laryngoscopy, and visual scopes, which use fiber-optic imagery and allow indirect visualization of the airway. They also can be used alone or in conjunction with direct laryngoscopy (Table 2).

VIEWING STYLETS Viewing stylets provide a view from the tip of the endotracheal tube. Whereas the view from a video laryngoscope is at the end of the laryngoscope, viewing stylets provide a view from the tip of the ET for steering the ET through the cords. The stylet size for this device allows it to be placed within an ET as an independent instrument, or as an adjunct to video or direct laryngoscopy. In addition, some can be used to

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Special Airway Techniques AWAKE INTUBATION For managing patients in whom a difficult airway is suspected or anticipated, securing the airway before induction of general anesthesia adds to the safety of anesthesia and helps minimize the possibility of major complications, including hypoxic brain damage and death. To perform awake intubation, the patient must be adequately prepared for the procedure. Good topical anesthesia is essential to obtund airway reflexes and can be provided by various topical agents and administrative devices (Table 6). Other relatively new devices

can be used to best position patients and maintain an open airway during awake intubation (Table 7).

Atomizing devices currently available for delivering topical anesthesia to nasal, oral, pharyngeal, laryngeal, and tracheal tissues include the DeVilbiss Model 15 Medical Atomizer (DeVilbiss Healthcare), the Enk Fiberoptic Atomizer Set (Cook Medical), and the LMA MADgic Laryngo-Tracheal Atomizer (LMA North America, a Teleflex Company). Although any technique of tracheal intubation can be performed under topical anesthesia, flexible fiber-optic intubation is most commonly used.

FLEXIBLE FIBER-OPTIC INTUBATION Flexible fiber-optic intubation is a very reliable approach to difficult airway management and assessment. It has a more universal application than any other technique. It can be used orally or nasally for both upper and lower airway problems and when access to the airway is limited, as well as in patients of any age and in any position. Technological advances—including improved optics, battery-powered light sources, better aspiration capabilities, increased angulation capabilities, and improved reprocessing procedures have been developed. The Airway Mobilescope (MAF; Olympus) is a portable, flexible endoscope with expanded viewing and recording capability, incorporating a monitor, LED light source, battery and recording device in a single unit. A completely disposable system, the aScope (Ambu) also is available. Rescue techniques, such as direct laryngoscopy and placing a retrograde guidewire through the suction channel, may be used if the glottic opening cannot be located with the scope, or if blood or secretions are present. Insufflation of oxygen or jet ventilation through the suction channel may provide oxygen throughout the procedure, and allow additional time when difficulty arises in passing the ET into the trachea.

RETROGRADE INTUBATION Retrograde intubation (Table 6) is an excellent technique for securing a difficult airway either alone or in conjunction with other airway techniques. Every anesthesia care provider should be skilled in employing this simple, straightforward technique. It is especially useful in patients with limited neck mobility (that is associated with cervical spine pathology, or in those who have suffered airway trauma). Cook Medical has 2 retrograde intubation sets: a 6.0 Fr for placing tubes of 2.5 mm or greater ID, and a 14.0 Fr for placing tubes of 5.0 mm or greater ID.

TRANSTRACHEAL JET VENTILATION Transtracheal jet ventilation (TTJV) is a well-accepted method for securing ventilation in rigid and interventional bronchoscopy, and there are several commercial manual jet ventilation devices available (Table 6).

The Enk Oxygen Flow Modulator (Cook Medical) is a device recommended for use when jet ventilation is appropriate but a jet ventilator is not available. A MRI

Conditional 3.0 Tesla manual jet ventilator (Anesthesia Associates, Inc., AincA) is also now available to enable TTJV in the MRI suite for both planned and emergency procedures (Table 6).

CRICOTHYROTOMY Cricothyrotomy (Table 8), a lifesaving procedure, is the final option for “cannot-intubate, cannot-ventilate” patients according to all airway algorithms, whether they concern prehospital, emergency department, intensive care unit, or operating room patients.

In adults, needle cricothyrotomy should be performed with catheters at least 4 cm and up to 14 cm in length. A 6 Fr reinforced fluorinated ethylene propylene Emergency Transtracheal Airway Catheter (Cook Medical) has been designed as a kink-resistant catheter for this purpose.

Percutaneous cricothyrotomy involves using the Seldinger technique to gain access to the cricothyroid membrane. Subsequent dilation of the tract permits passage of the emergency airway catheter. Surgical cricothyrotomy is performed by making incisions through the cricothyroid membrane using a scalpel, followed by the insertion of an ET. This is the most rapid technique and should be used when equipment for the less invasive techniques is unavailable and speed is particularly important.

TRACHEOSTOMY Tracheostomy (Table 9) establishes transcutaneous access to the trachea below the level of the cricoid cartilage. Emergency tracheostomy may be necessary when acute airway loss occurs in children under 10 years of age or children whose cricothyroid space is considered too small for cannulation, as well as in individuals whose laryngeal anatomy has been distorted by the presence of pathologic lesions or infection.

Percutaneous dilatational tracheostomy is the most commonly performed tracheostomy technique, yet it is still considered invasive and can cause trauma to the tracheal wall. Translaryngeal tracheostomy, a newer tracheostomy technique, is considered to be safe and costeffective, and it can be performed at the bedside. It may be beneficial in patients who are coagulopathic. Surgical tracheostomy is more invasive, and should be performed on an elective basis and in a sterile environment.

Conclusion Most airway problems can be solved with relatively simple devices and techniques, but clinical judgment born of experience is crucial to their application. As with any intubation technique, practice and routine use will improve performance and may reduce the likelihood of complications. Each airway device has unique properties that may be advantageous in certain situations, yet limiting in others. Specific airway management techniques are greatly influenced by individual disease and anatomy, and successful management may require combinations of devices and techniques.

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Table 1. Endotracheal Tube Guides Name (Manufacturer)

Description

Length, cm

Aintree Intubation Catheter (Cook Medical)

Polyethylene 19 Fr AEC allows passage of an FOB through its lumen.

Has 2 distal side holes and is packaged with Rapi-Fit adapters.

Color: light blue.

56

Arndt Airway Exchange Catheter Set (Cook Medical)

Polyethylene 8 and 14 Fr AEC with a tapered end, multiple side ports, packaged with a stiff wire guide, bronchoscope port, and Rapi-Fit adapters. Color: yellow.

50, 65, 78

Cook Airway Exchange Catheters (Cook Medical)

8, 11, 14, and 19 F Polyethylene designs facilitate exchange of SLT or DLT of ≥ 4.0 mm ID. The DLT versions are extra firm with soft-tips.

Colors: Yellow, green; soft-tip is purple.

43, 83, 100

Cook Staged Extubation Set (Cook Medical) (Available outside of USA only)

Soft-tipped marked extubation wire to maintain continuous airway access, wire holder and Tegaderm for securement, soft-tipped Reintubation Catheter, Rapi-Fit adapters to assist in oxygen delivery, if necessary.

This set can facilitate reintroduction of ETs with ID >5 mm.

CoPilot VL Single-Use Bougie (Magaw Medical)

14 Fr polyethylene single-use ET introducer with coudé tip.

60 cm length. For use with ETs ≥6.0 mm ID.

CoPilot VL Rigid Stylet (Magaw Medical)

Reusable CoPilot VL intubation stylet.

For use with ET ≥6.0 mm ID.

Frova Intubating Introducer (Cook Medical)

Polyethylene 8 and 14 Fr AEC with angled distal tip with 2 side ports.

Has hollow lumen and is packaged with a stiffening cannula and removable Rapi-Fit adapters. 14 Fr also packaged in box of 10.

Colors: 8 Fr, yellow; 14 Fr, blue.

35, 65

GlideRite Rigid Stylet (Verathon)

Reusable, sterilizable, semirigid stylet that conforms to GlideScope unique blade angulation; provides improved maneuverability in ET placement.

Stylet rod length is 26.6 cm. Accommodates ETs ≥6.0 mm ID.

Introes Pocket Bougie (BOMImed)

Single-use 14 Fr (4.7 mm) malleable ET introducer made from special blend of Teflon. Packaged in box of 10.

60 accommodates ETs ≥5.0 mm ID.

Muallem ET Tube Stylet (VBM Medizintechnik GmbH)

Single-use 8, 12, 14 Fr stylet; malleable, but with soft and atraumatic coudé tip. Color: green.

40, 65

OptiShape Stylet (Truphatek International Ltd)

Reusable, sterilizable, semirigid stylet with optimal shape memory for indirect intubation procedures.

4 sizes. Accommodates ETs 2.5-3.5, 4.0-5.5, 5.0-6.5, and 7.0-9.0 mm ID.

Pocket Introducer (VBM Medizintechnik GmbH)

Single-use 15 Fr Introducer with coudé tip. Color: blue.

65

Portex Venn Tracheal Tube Introducer (Smiths Medical)

15 Fr ET introducer made from a woven polyester base, with a coudé tip (angled 35 degrees at its distal end). Also known as the gum elastic bougie. Color: golden brown.

60

Single-Use Bougie (Smiths Medical)

15 Fr, PVC ET introducer with coudé tip. Has a hollow lumen that discourages reuse and is provided sterile. Color: ivory.

70

Truflex Flexible Stylet (Truphatek International Ltd)

Reusable, stainless steel stylet. Has flexible tip with upward lift action of 30-60 degrees, depending on size of ET.

Suitable for use with ETs 6.5-8.5 mm ID.

VBM Introducer (VBM Medizintechnik GmbH)

Single-use 15 Fr introducer with coudé tip and hollow for oxygenation.

Color: orange.

65

VBM Tube Exchanger (VBM Medizintechnik GmbH)

Single-use 11, 14, and 19 Fr tube exchanger that is hollow to allow oxygenation. Color: blue.

80

Abbreviation key for all tables is on page 72.

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Clinical Applications

Special Features

Exchange of SGAs for ETs ≥7.0 mm using an FOB. Its hollow lumen allows insertion of an FOB directly through the catheter so that the airway can be indirectly visualized.

Large lumen (4.7 mm) allows passage of FOB. Rapi-Fit adapters allow both jet ventilation and ventilation with 15-mm adapter (anesthesia circuit or Ambu bag). Single use.

Exchange of LMAs and ETs using an FOB.

Tapered end and multiple side ports. Rapi-Fit adapters allow both jet ventilation and ventilation with 15-mm adapter (anesthesia circuit or Ambu bag). Single use.

The Cook airway exchange catheter is intended for uncomplicated, atraumatic, ET exchange for both single- and double-lumen tubes.

EF with 2 distal side holes. The soft-tip version offers a more flexible tip to help minimize tracheal trauma.

Rapi-Fit adapters as above, but should be used primarily for jet ventilation because of length. Single use.

Provides a tool for a more complete extubation strategy, which should be in place for every patient.

Utilizes an atraumatic wire to maintain continuous airway access and a soft-tipped reintubation catheter to facilitate a successful reintubation if required and delivery of oxygen when desired.

Facilitate endotracheal intubation.

Designed to shape the ET and facilitate intubation with VL. Facilitates endotracheal intubation and allows simple ET exchange. Can also be used by placing it first in the ET, with its tip protruding, or placing it directly into the glottis and then placing the ET over it.

Can be used in pediatric population for ETs as small as 3.0 mm. Hollow lumen allows oxygenation/ventilation in all sizes.

Single use.

Designed to work with GlideScope AVL, GVL, Cobalt, and Ranger video laryngoscopes to facilitate intubations in OR, ED, and emergency settings.

Reusable, durable stainless steel; easy to clean and sterilize in an autoclave.

Designed to facilitate endotracheal Intubation for both direct and video laryngoscopy. Unique curvature designed to follow natural path of the airway. Flexibility allows for manipulation of distal tip for anterior airways. Customizable coudé tip angles.

Self-lubricated bougie, Tactiglide technology for tactile sensation, optimal curve with shape memory, balanced rigidity with soft tissue protection, non-removable depth markings, packaged sterile.

Difficult intubation.

Malleable stylet with soft coudé tip and graduation marks for insertion depth.

Facilitates smooth passage of ET in both routine and difficult intubations. Especially useful in combination with the variety of video laryngoscopes that employ >42-degree angles. Designed with the ideal curve to closely follow the blade shape and ensure successful passage of ET through vocal cords.

Easily adjustable to a variety of ET sizes. Suitable for use in combination with a variety of video laryngoscopes that employ >42-degree angle of vision.

Facilitates endotracheal intubation.

Folded to only 20 cm, unfolds to 65 cm within seconds, ideal space solution for emergency bags.

Proven useful in patients with an anterior larynx (grades 2b, 3, and 4) and those with limited mouth opening. Can be used by slightly protruding through the ET, or placing it directly into the glottis and then placing an ET over it.

Non-disposable and reusable. Size 5 Fr is single use. Has memory properties. Coudé tip effectively detects “tracheal clicks” to confirm correct placement. Part of a range of introducers, stylets, and guides for adults and pediatrics. Can be reused after cold-water disinfection.

Single-use product reduces the risk for cross-contamination.

Otherwise, same as Portex Venn Tracheal Tube Introducer.

Similar to Portex Venn Tracheal Tube Introducer, but hollow lumen allows oxygenation/ventilation. Single use.

Eases clinical coordination difficulties associated with use of video laryngoscopes by providing greater control of ET tip direction.

Adjustable stopper allows use with e-tubes of differing lengths.

Difficult intubation with oxygenation possibility.

Supplied with unique removable connector to allow oxygenation with 15-mm connector or jet. Graduation marks for insertion depth.

Exchange of tracheal tubes.

Similar to Muallem ET Tube Introducer.

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Table 2. Stylets Name (Manufacturer)

Description

Size

Aaron Surch-Lite (Bovie Medical Industries, Inc.)

10-in sterile, single-use, flexible stylet.

Adult.

AincA Lighted Stylet (Anesthesia Associates, Inc.)

Easily malleable, lighted stylet with adjustable ET holder. Shapes and guides ET while forwardly illuminating the passage. Completely reusable device consisting of removable handle with xenon bulb.

Adult and children (ETs ≥5 mm).

Infant (ETs ≥3 mm).

Rüsch Trachlight Stylet & Tracheal Light Wand (Teleflex Medical)

Consists of 3 parts: a reusable handle, a flexible wand, and a stiff retractable stylet.

Available in 3 sizes: adult, child, and infant. Accommodates ETs 3.0-10.0 mm ID.

Tube-Stat Lighted Intubation Stylet (Medtronic)

Similar to AincA lighted stylet.

Nasotracheal: 33 cm shaft. Orotracheal: 25 cm shaft.

Vital Signs Light Wand Illuminating Stylet (GE Healthcare)

Similar to AincA lighted stylet.

Adult.

AincA VideoStylet (Anesthesia Associates, Inc.)

Malleable, cost-effective (<$500 capital limit), and self-contained video imaging stylet with built-in ET stop. CCD camera and LED illumination (in stylet tip) provide clear image to detachable 2.4-in full-color rechargeable LCD monitor (110v ac/USB lithium-ion battery charging system). System completely reusable and easy to clean (sterilize by glutaraldehyde or Sterrad) with 3 different stylet lengths available. Simple set-up and onehanded operation; appropriate for OR, ED, office and field use.

5.8 mm OD tip. Adult and children (ETs ≥6 mm).

air-Vu Plus Fiber-optic Stylet (Cookgas LLC; distributed by Mercury Medical)

High-resolution, stainless steel, rigid stylet. Incorporates an adjustable tube stop and optional oxygen port for oxygen insufflation.

Adult (ETs ≥5.5 mm).

Ambu aScope 3 (Ambu Inc.)

Single-use flexible videoscope. OD: 5.0 mm; working channel ID: 2.2 mm.

60 cm long.

Ambu aScope 3 Slim (Ambu Inc.)

Single-use flexible videoscope. OD: 5.0 mm; working channel ID: 2.2 mm.

60 cm long.

Bonfils Retromolar Intubation Endoscope (KARL STORZ Endoscopy)

High-resolution rigid fiber-optic stylet with a fixed 40-degree curved shape at the distal end. Available with a standard eyepiece or with a DCI to endoscopic camera system. Can be used within the C-MAC system while using the portable monitor of the C-MAC VL with C-CAM camera head.

3.5 and 5.0 mm OD. ET must be ≥0.5 mm larger to fit.

Brambrink Intubation Endoscope (KARL STORZ Endoscopy)

High-resolution semi-rigid fiber-optic stylet with a 40-degree curved shape at the distal end, 40× magnification, a fixed eyepiece, a movable ET holder, and an insufflation port.

2.0 mm OD. ET must be ≥0.5 mm larger to fit.

Lighted Stylets

Viewing Stylets

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Clinical Applications

Special Features

Although usable for routine blind intubations or additional illumination during laryngoscopy, it is especially useful when the FOB is unavailable (eg, outside locations or ambulances), or when bronchoscopy is difficult to perform (eg, obscured airway or limited head motion allowed).

Can be used alone or with other techniques. System is completely disposable. Intended for single use. Individually packaged in boxes of 3.

Same as Aaron Surch-Lite.

Can be used alone or with other techniques. Handle-mounted xenon light source is always on and keeps stylet tip cold. Uses 2 AA batteries. System is completely reusable and sterilizable.

Although it can be used for routine intubations, it is especially useful in situations in which the FOB is unavailable (eg, in ambulances or outside locations), or in which bronchoscopy is difficult to perform (eg, when an airway is obscured by blood or secretions or when a patientâ&#x20AC;&#x2122;s head cannot be flexed or extended).

Blind technique that can be used alone or with other techniques.

Ideal for difficult intubations, teaching.

Minimizes neck flexion and head hyperextension in trauma cases.

Although usable for routine intubations or video imaging during laryngoscopy, it is especially useful when the FOB is unavailable (eg, outside locations or ambulances), or when bronchoscopy is difficult to perform (eg, obscured airway or limited head motion allowed). Low price allows for multiple units in all critical locations and reusable nature ensures economy of use.

Provides rapid learning curve due to similarity to standard ET advancement techniques, but with the added benefit of an attached, clear video image of all landmarks forward of the ET tip. Allows for one-handed use with imaging or used in conjunction with a laryngoscope, as desired for physical alignment.

Allows for visualization during intubation through an air-Q laryngeal mask.

A portable, durable rigid stylet that allows for a fiber-optic view during intubation through the air-Q. Light source options include GreenLine laryngoscope handle or fiber-optic light source (4 AA batteries).

Alternative to standard reusable flexible bronchoscopes. Useful for visualization during intubation through SGAs.

Fully disposable flexible scope avoids cleaning/disinfecting issues. Attaches to high-quality aView Monitor with on-board recording of video images.

Equivalent to standard reusable pediatric flexible bronchoscopes. Especially useful for positioning double lumen endobronchial tubes or bronchial blockers.

Fully disposable flexible scope avoids cleaning/disinfecting issues. Attaches to high-quality aView Monitor with on-board recording of video images.

Able to elevate a large, floppy epiglottis and navigate through the oropharynx of patients with excessive pharyngeal soft tissue, midline obstruction, limited mouth opening, or fragile veneers on incisors.

Fixed-shape shaft with an adjustable eyepiece that allows ergonomic movement during intubation, in addition to an adapter for fixation of ETs and oxygen insufflation. Portable, rugged, and better maneuverability than the flexible FOB. Used with a battery-powered or portable light source.

Similar to Bonfils Retromolar Intubation Fiberscope.

Available for DCI video cameras.

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Table 2. Stylets

(continued)

Name (Manufacturer)

Description

Size

Clarus Video System 30000V (Clarus Medical)

Malleable (shapeable) rigid stylet scope with attached LCD screen and adjustable curve shape provides view from end of stylet; USB for recharging lithium ion battery and option to connect to notebook or monitor; red LED for transillumination. Assist with DL/VL or used as independent device. Also malleable to be used through intubating supraglottic ventilatory devices.

5 mm OD. ETs ≥5.5 mm.

Levitan GLS (Clarus Medical)

Portable high-resolution optics from end of stylet, malleable (shapeable) rigid stainless steel stylet that protects the illumination optic fibers. Comes in a preformed hockey-stick shape that can be changed, if necessary. Builtin tube stop to hold ET in place with integral oxygen port for oxygen insufflation during intubation. Assist with DL/VL like regular stylet or used as independent device. Also malleable to be used through intubating supraglottic ventilatory devices. Optional adapter uses smartphones to transform optics to video.

Adult (ETs ≥5.5 mm ID).

PocketScope (Clarus Medical)

Conveniently sized, easy to clean, and cost-effective (reusable) flexible sty- Adult (ETs ≥4.0 mm let that has a patented, deflected, non-directable tip. Optional adapter uses ID). smartphones to transform optics to video. Often used to confirm placement and patency of airways.

SensaScope (Acutronic Medical Systems AG)

Hybrid S-shaped, semi-rigid fiber-optic intubation video stylet. Has a 3 cm steerable tip with video chip that can be flexed in sagittal plane 75 degrees in both directions with lever at proximal end of device. Has no working channel.

6.0 mm OD. ET must be >0.5 mm larger to fit.

Shikani Optical Stylet (SOS; Clarus Medical)

Viewing stylet: High-resolution, stainless steel, malleable (shapeable) fiberoptic stylet that comes in a preformed hockey-stick shape. Has an adjustable tube stop and integral oxygen port for oxygen insufflation. Use to assist with DL/VL like regular stylet or used as independent device. Also malleable to be used through intubating supraglottic ventilatory devices.

Optional adapter uses smartphones to transform optics to video.

Adult (ETs ≥5.5 mm ID). Pediatric (ETs 2.5-5.0 mm ID).

Table 3. Rigid/Video Laryngoscopes Name (Manufacturer)

Description

Size

Airtraq Avant (Prodol Meditec SA; distributed by Airtraq LLC)

Disposable video laryngoscope that provides a magnified angular view of the glottis without alignment of oral, pharyngeal, and tracheal axes. Includes a guiding channel to both hold and direct ET toward the vocal cords. Reusable optic piece (up to 50 intubations) and anti-fog heater resists lens clouding. Disposable blade and eyecup. MRI Conditional use. Also optional A-360 camera available and smartphone adapter.

Regular adult for ET 7.0-8.5 mm ID. Small adult for ET 6.07.5 mm ID.

Airtraq SP (Prodol Meditec SA; distributed by Airtraq LLC)

The SP model is single-use with all the features of the Avant but fully disposable. Both Airtraq models have an optional snap-on camera, with integrated 2.8-in touch screen that flips and rotates on 2 axes and can be attached to all Airtraq models. It records and can Wi-Fi connect to smartphone/iPad/iPhone/PC.

6 color-coded sizes available: regular adult for ET 7.0-8.5 mm ID; small adult for ET 6.0-7.5 mm ID; pediatric for ET 4.05.5 mm ID; infant for ET 2.5-3.5 mm ID; non-channeled blade; and double-lumen endobronchial tubes.

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Clinical Applications

Special Features

ET intubation, confirmation, extubation (with video); LMA placement, positioning, and intubation with certain LMAs. Provides access with limited mouth opening; malleable stylet provides shaping to reduce cervical movement.

Red LED provides better illumination than the white LED, and better transillumination when used like a light wand in cases when use of the scope is contraindicated because of blood or vomit.

Originally designed as an adjunct to direct laryngoscopy. Many use it as a stand-alone device similar to the Shikani for intubation, cric/trach tubes, LMAs, and intubation through LMAs or just positioning or checking placement of the same.

GreenLine laryngoscope handle or a Turbo LED can be used for light sources. Very similar to the SOS, but requires the user to cut the ET because it does not have a movable tube stop.

Allows for visualization during intubation through ILMA or quick confirmation of SGA, DLTs, or ET placement/positioning patency.

May also be used for extubation.

This device has been modified with a patented deflected tip that allows it to be used for viewing while performing nasal intubation.

Similar to Brambrink Intubation Endoscope.

Offers an improved view of glottis, simultaneous direct and endoscopic views, full visual control over passage of ET, and confirmation of final position. No need for extreme head extension or forced traction of laryngoscope. Can be rapidly assembled for immediate use.

Similar to flexible FOB. Can be used alone or as an adjunct to laryngoscopy and is especially useful for those unable to maintain skills with a bronchoscope.

Has the simple form of a standard stylet, plus the advantage of a fiber-optic view and maneuverability of its tip. Portable, rugged, and able to lift tissue. Light source options are light cable, Turbo LED or GreenLine laryngoscope handle with adapter.

Clinical Applications

Special Features

Intended to facilitate intubation in both routine and difficult airway situations. Useful in all cases where ET intubation is desired. Also appropriate for emergency settings, cervical spine immobilization, fiberscope guidance, tube exchange, and foreign body removal.

Optics fully isolated from patient, preventing cross-contamination. Advanced airway device with built-in anti-fog system, and low-temperature light source. Can be used with standard ETs. Integral tracking channel allows ET to be directed without a stylet or bougie. May be used in MRI suite as MRI-compatible.

Same as Airtraq Avant.

Same as Airtraq Avant but totally disposable and self-contained.

3-year shelf-life.

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Table 3. Rigid/Video Laryngoscopes

(continued)

Name (Manufacturer)

Description

Size

Berci-Kaplan DCI Video Laryngoscope System (KARL STORZ Endoscopy)

Video laryngoscope system with interchangeable laryngoscope blades. Platform system enables a DCI camera head to snap onto any standard eyepiece fiberscopes (flexible or semi-rigid).

Required components include a camera control unit, xenon light source, and monitor. Telepack portable combination video/light source/monitor unit is also available for use with this system.

MAC 2-4, Miller 0, 1, 4, Dรถrges universal blade and D-Blade for difficult very anterior airways.

C-MAC Video Laryngoscope (KARL STORZ Endoscopy)

Instant on, battery-powered video laryngoscope with standard shaped interchangeable Macintosh and Miller blades for obese adults through neonates as well as a difficult airway blade (D-Blade) for very anterior airways. Blades house high-resolution CMOS distal chip and LED technology. Real-time viewing on 7-inch LCD monitor. Dรถrges D-Blade has angle of view that is approximately 80 degrees acute curvature design.

Highly portable rescue device, 2.4-in monitor fits directly on all C-MAC blades. LCD 4.3 ratio high-resolution screen works in direct sunlight; rechargeable battery lasts one hour; ergonomic screen can be moved in several directions and folded away for transportation; fully immersible.

Next-generation portable VL with an acutely angled blade and C-shaped channel for a bougie. Rechargeable lithium polymer internal battery provides over 2 hours of continuous use. Built-in anti-fog mechanism.

GlideScope Titanium systems are available in reusable options and feature streamlined, low-profile blade designs and durable, lightweight titanium construction. Built-in anti-fog mechanism. With new snapshot and on-screen playback features.

MAC 2-4, Miller 0 and 1, MAC 3 and 4 with channel for suction, D-Blade, and S-Blade (single-use).

C-MAC Pocket Monitor (KARL STORZ Endoscopy)

CoPilot VL (Magaw Medical)

GlideScope Titanium Video Laryngoscope (Verathon)

GlideScope AVL (Advanced Video Laryngoscope; Verathon)

Portable advanced VL features a digital color monitor and digital camera for DVD clarity. Also includes integrated real-time recording and onboard video tutorial. Anti-fog feature to resist lens fogging. Reusable and single-use options available. With new snapshot and on-screen playback features.

GlideScope Ranger and Ranger Single Use Video Laryngoscopes (Verathon) King Vision Video Laryngoscope (Ambu Inc.)

Portable video laryngoscope designed for EMS and military paramedics. Compact and rugged. Operational in seconds.

King Vision Video Laryngoscope aBlade System (Ambu Inc.) McGrath MAC (Aircraft Medical Ltd; distributed by Covidien)

Reusable video adapter attaches to the existing King Vision display to allow use of lower-cost aBlades.

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Durable, fully portable digital video laryngoscope with a highquality reusable display and disposable blades. Display aligned with blade, ergonomic handle integrated into blade, the disposable blades incorporate the camera and light source, antifog coating on distal lens. Channel is soft, allowing for easy ET detachment.

Portable VL designed for everyday use in the OR, ICU, and ED. Uses disposable Macintosh shaped blades as well as acutely curved X3 Blade. Durable (drop tested up to 2 m). Screen displays minute-by-minute battery life countdown.

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Same as C-MAC.

Adult sizes 3 and 4.

4 reusable blade designs.

LoPro 3 and 4 angled blades, and Mac-style 3 and 4 blades. Compatible with full line of GlideScope AVL pediatric blades.

6 disposable blades, sizes 0-4.

Reusable blades in 4 sizes: GVL 2-5.

Reusable Ranger offers 2 blade sizes, 3 and 4. Ranger Single Use is offered with 6 disposable Stats sizes 0-4.

One size, 2 versions, correlating to size 3 laryngoscope.

Channeled blade allows use of 6.0 to 8.0 mm ET and minimum mouth opening of 18 mm.

Standard blade requires minimum mouth opening of 13 mm.

Same as original offering: size 3 with channeled and standard (non-channeled) aBlade versions.

Blade sizes 2, 3, and 4 and X3.

Clinical Applications

Special Features

Useful for anterior airways, obese patients, and patients with limited mouth opening or neck extension. Variety of blade sizes and designs accommodates patients ranging from morbidly obese to neonate (500 g). Additionally useful for teaching purposes, verification of ET position, aiding application of external laryngeal manipulation, or passage of an intubating introducer. May also be used for nasal intubation and ET exchange.

Same as DCI. Highly portable system for use in all hospital settings.

The wide-angle camera allows improved visualization and video documentation of laryngoscopy and intubation. Extreme positioning of the head is unnecessary. Blades provide 80-degree field of view.

Ideal for ICU, crash carts, ED and all prehospital environments including EMS, ambulatory services, air transport, and military. Has familiar blade design and 80-degree field of view.

Unique platform design is compatible with multiple intubation devices, including video laryngoscopes, the F.I.V.E. distal chip flexible video scopes, and standard eyepiece scopes (fiber-optic and semi-rigid) via C-CAM camera head.

Built-in still and video image capture on memory card, with real-time playback on monitor. Angled distal lens provides 80-degree field of view. Inherent antifog design. Unit can be pole-mounted or inserted into waterproof field bag. No special ETs or stylets needed. Can be used while battery is charging.

Lightweight, handheld, and battery-operated device well suited for areas outside the OR. Waterproof.

Same as DCI.

Patent-pending Bougie Port is designed to enhance glottic entry. A 14 Fr suction catheter, FOB, reusable rigid stylets, or regular malleable stylets may also be used via this port. A built-in heating mechanism helps prevent fogging.

More VL options for routine and difficult airways— including new Mac-style blades—provide clinicians with a choice of airway tools for a wide range of patients, clinical settings, and teaching purposes.

Reusable blades and video cable, as well as the single-use Smart Cable, can be completely immersed in the recommended cleaning solution (IPX8 compliant). Includes anti-fog capability, plus real-time recording, display, and playback features on 6.4-in digital, color GlideScope Video Monitor.

DVD-quality airway view enables intubation in a wide range of adult and pediatric patients, including preterm/small child and morbidly obese, bloody or anterior airways, and patients with limited neck mobility. Optimized for demanding applications in the OR, ED, ICU, and NICU. Can be used for teaching.

Ideal for EMS (ground and air), military, ED, ICU, and crash cart settings. Offers same benefits as AVL, GVL.

Real-time recording, onboard video tutorial, anti-fog feature to resist lens fogging, advanced resolution output to an external monitor, intuitive user controls and status icons, lightweight and easily transportable, impact-resistant, durable polycarbonate-coated video screen. Disposable blades allow quick turnaround and help limit the possibility of cross-contamination.

Facilitates both routine and difficult intubations.

Ranger models are compact, rugged, portable, and built to military and EMS specifications. Powered by rechargeable lithium polymer battery; 1.5 lb.

Awarded US Army Airworthiness and US Air Force Safe-to-Fly certifications.

Reusable and disposable.

Can be used alone or with other techniques. Powered by 3 AAA batteries.

OLED screen allows wide-angle viewing in various lighting conditions. Video out available for connection to external display or video capture device.

Facilitates both routine and difficult intubations.

Can be used alone or with other techniques. Powered by 3 AAA batteries; high fidelity 2.4-in screen allows wide-angle viewing. Video out available for connection to external display or video capture device.

Its dual capability combines the benefits of a video-supported anterior view as well as a direct visualization to support a wide range of airways from routine to more extreme cases.

Does not require additional training. Supports direct and indirect visualization due to video support. Blade is very slimline for improved agility. Blade shape requires less tube curvature than other video laryngoscopes for easier insertion and a stylet is not always required. Highly portable and lightweight.

Does not require an electrical outlet and thus is ideal for settings outside the OR. Uses disposable blades for quick turnaround between uses and for limiting cross-contamination. The monitor is located on the handle to remain in a more natural line. Waterproof. table continues on next page

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Table 3. Rigid/Video Laryngoscopes

(continued)

Name (Manufacturer)

Description

Size

McGrath Series 5 Video Laryngoscope (Aircraft Medical Ltd; distributed by LMA North America, a Teleflex Company)

Portable VL with adjustable-length single-use disposable blade that can be disarticulated from the handle to further assist with difficult airways. The flat screen monitor is located on the handle to remain in a more natural line of sight with the patient.

Adjusts to fit many adult and pediatric sizes.

Truview PCD-R Optical Laryngoscope blades with recording capabilities (Truphatek International Ltd)

Fully portable, lightweight and compact system with interchangeable, low-profile, stainless steel 47-degree angled narrow tip laryngoscope blades with built-in oxygen delivery system. Can be used independently or magnetically linked to the camera and 5-in LCD color monitor with picture and video recording capabilities.

Blade sizes 0, 1, 2, 3, and 4.

Venner AP Advance Video Laryngoscope (Venner Capital S.A.)

Fully portable VL with 3.5-in monitor that attaches to a reusable handle. Self-contained LED light source. Built-in anti-fogging mechanism.

MAC 3 and 4, and Difficult Airway Blade.

VividTrac (Mercury Medical/FujiFilm/ SonoSite)

Video intubation device that works on many computer systems equipped with USB II port as a standard USB camera, using available video camera applications on Windows, Mac, and Linux systems. Alternatively, automated video display software (VividVision) can be downloaded.

ET 6.0-8.5 mm.

The McGrath Series 5 HLDi is the new “High Level Disinfection Immersible” system that is entirely waterproof.

Table 4. Indirect Rigid Fiber-Optic Laryngoscopes Name (Manufacturer)

Description

Size

Dörges Emergency Laryngoscope Blade (KARL STORZ Endoscopy)

Developed in Europe as a universal blade that combines features of both the MAC and Miller laryngoscope blades.

One size only for patients >10 kg to adult.

Flexible tip or levering fiber-optic MAC laryngoscope blades are designed with a hinged tip controlled by a lever at the proximal end. Designed to fit standard handles.

Adult sizes 3 and 4. Pediatric size 2.

Modified MAC Blades AincA Flex-Tip Fiber-Optic Laryngoscope Blade (Anesthesia Associates, Inc.) Flipper (Teleflex Medical)

Adult sizes only.

Heine Flex Tip Fiber-Optic Laryngoscope Blade (Heine USA, Ltd.) AincA Macintosh Viewing Prisms (Anesthesia Associates, Inc.)

An optically polished viewing prism for attachment to most Macintosh laryngoscope blades (conventional OR fiber-optic).

Effectively repositions the practitioner’s viewpoint to the forward portion of the MAC curve via a 30-degree refraction without inverting the image. Clips to the vertical flange of the MAC to “look around the curve of the blade.”

Sizes 2, 3, and 4 for use on Macintosh laryngoscope blades of sizes 2, 3, and 4.

Rüsch Truview EVO (Truphatek International Ltd; distributed by Teleflex Medical)

Indirect rigid laryngoscope with specially designed 42-degree blade curvature; fits onto all standard endoscopic camera heads.

Provides clear, unmagnified view of the glottis. Oxygen channel for demisting, clearing secretions, and insufflation.

Adult, small adult, and infant sizes.

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Clinical Applications

Special Features

Useful in patients with limited mouth opening or head and neck movement, anterior airways; obese patients; patients in whom an increased hemodynamic response is a concern; and for teaching.

Highly portable and lightweight. Uses disposable blades for quick turnaround between uses and for limiting cross-contamination. An adjustable blade allows use of different blade lengths on the spot. Low-profile blade and disarticulating handle can accommodate patients with very limited mouth opening and severely limited movement of the head and neck. The monitor is located on the handle to remain in a more natural line of sight with the patient.

Difficult intubation cases where mouth opening and neck extension are limited and stable oxygen saturation levels are critical.

Blades can be linked to STORZ HD or other endoscopic systems.

Similar to C-MAC VL.

Can be used as traditional laryngoscope and converted to video laryngoscope by attachment of monitor.

Intended to facilitate intubation in both routine and difficult airway situations.

VividTrac is inserted more like an oral airway device (or LMA) than a laryngoscope blade. The ET can be preloaded or inserted once visualization is achieved in the VividTrac tube channel.

Clinical Applications

Special Features

Blade is inserted into the oropharynx to the appropriate depth, which correlates with the patientâ&#x20AC;&#x2122;s size.

Has 10-kg and 20-kg markings on the blade.

Controlled manipulation of large or floppy epiglottis. Also useful in patients with a recessed mandible and decreased mouth opening.

A lever controls the tip angle through 70 degrees during intubation to lift the epiglottis, if necessary, to improve laryngeal visualization.

Useful in patients with a recessed mandible and decreased mouth opening.

Allows viewing of the vocal cords even in a patient with an anterior airway position. Also useful during nasal intubation (with impaired view) and for postoperative examination of the larynx.

A built-in clip on each prism allows attachment to any Macintosh-type laryngoscope blade that has a standard thickness vertical flange. Usable on both conventional and fiber-optic type MAC blades. Reusable and sterilizable.

Useful for difficult adult and infant airways, including patients with an anterior airway and limited neck extension.

Rugged, portable, easy to maintain. Depth lines on the blade to guide insertion. Can be used with all fiber-optic laryngoscope handles. Designed to provide indirect laryngoscopy with continuous oxygen insufflation. Infant size features an LED light and rechargeable battery.

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Table 5. Selected Supraglottic Ventilatory Devices Name (Manufacturer)

Description

Size

AES The Guardian CPV (AES, Inc.)

All-silicone laryngeal mask with a vented gastric tube and CPV that constantly monitors cuff pressure.

Adult sizes 3, 4, 5.

AES Ultra (AES, Inc.)

All-silicone laryngeal mask with standard cuff valve.

Adult sizes 3, 4, 5, 6.

AES Ultra Clear (AES, Inc.)

Silicone cuff and PVC tube, laryngeal mask with standard cuff valve.

Adult sizes 3, 4, 5, 6.

AES Ultra Clear CPV (AES, Inc.)

Silicone cuff and PVC tube, laryngeal mask with cuff pilot valve (CPV) that constantly monitors cuff pressures.

Pediatric to adult sizes 1, 1½, 2, 2½, 3, 4, 5, 6.

AES Ultra CPV (AES, Inc.)

All-silicone laryngeal mask with CPV that constantly monitors cuff pressures.

Pediatric to adult sizes 1, 1½, 2, 2½, 3, 4, 5, 6.

AES Ultra EX (AES, Inc.; distributed by Anesthesia Associates, Inc.)

All-silicone, multiple-use laryngeal mask (40 uses).

Pediatric to adult sizes 1, 1½, 2, 2½, 3, 4, 5, 6.

AES Ultra Flex CPV (AES, Inc.)

Wire-reinforced, silicone cuff and tube with CPV that constantly monitors pressure changes in the cuff.

Pediatric to adult sizes 1, 1½, 2, 2½, 3, 4, 5, 6.

AES Ultra Flex EX (AES, Inc.; distributed by Anesthesia Associates, Inc.)

All-silicone, wire-reinforced, multiple-use laryngeal mask (40 uses).

Pediatric to adult sizes 1, 1½, 2, 2½, 3, 4, 5, 6.

air-Q Blocker Disposable Laryngeal Mask (Cookgas LLC; distributed by Mercury Medical)

Combines the features of air-Q Disposable Laryngeal Mask, with an additional soft flexible guide tube located to the right of the breathing tube. This channel provides access to the esophagus with a nasogastric tube or Blocker tube that allows clinicians to vent, suction and further block the esophagus.

Sizes (2.5, 3.5, and 4.5) that can accommodate standard ETs up to 8.5 mm. Also available in kits with syringe and lubricant packet.

air-Q Disposable Laryngeal Mask (Cookgas LLC; distributed by Mercury Medical)

Hypercurved intubating laryngeal airway with removable colorcoded connectors. Anterior portion of mask is recessed; a larger mask cavity allows intubation using standard ETs. Air-Q removal after intubation is accomplished by using air-Q reusable removal stylet.

Sizes (1.0, 1.5, 2.0, 2.5, 3.5, and 4.5) that can accommodate standard ETs up to 8.5 mm.

air-Q Reusable Laryngeal Mask (Cookgas LLC; distributed by Mercury Medical)

Hypercurved intubating laryngeal airway that resists kinking, and removable airway connector. Anterior portion of mask is recessed; a larger mask cavity allows intubation using standard ETs. Air-Q removal after intubation is accomplished by using air-Q reusable removal stylet.

Sizes (0.5, 1.0, 1.5, 2.0, 2.5, 3.5, and 4.5) that can accommodate standard ETs 4.0-8.5 mm.

air-Q SP (Cookgas LLC; distributed by Mercury Medical)

Combines the features of the air-Q disposable laryngeal masks Sizes (1.0, 1.5, 2.0, 2.5, 3.5, 4.5) with the added advantage of a self-pressurizing mask. No infla- that can accommodate standard tion line or pilot balloon is needed. Positive Pressure ventilation ET tubes up to 8.5 mm. or Spontaneous breathing patients inflate the mask during the uptake of ventilation.

air-Q SP Reusable (Cookgas LLC; distributed by Mercury Medical)

Combines the features of the air-Q reusable laryngeal masks Sizes (0.5, 1.0, 1.5, 2.0, 2.5, 3.5, with the added advantage of a self-pressurizing mask. No infla- 4.5) that can accommodate stantion line or pilot balloon is needed. Positive pressure ventilation dard ETs 4.0-8.5 mm. or spontaneously breathing patients inflate the mask during the uptake of ventilation.

Ambu AuraFlex (Ambu Inc.)

Disposable wire-reinforced flexible LMA.

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Adult and pediatric sizes 2-6.

Clinical Applications

Special Features

Similar to LMA Supreme, but with built-in CPV to minimize postoperative sore throat. Color indicator bands provide instant feedback regarding pressure changes.

The CPV detects changes caused by temperature, nitrous oxide levels, and movement within the airway, enabling clinician to maintain a recommended cuff pressure of 60 cm H2O. Single use.

Standard all-silicone SGA.

All silicone. Single use.

Combines all-silicone cuff with PVC tube for cost savings.

All-silicone cuff with PVC tube. Single use.

Similar to AES Ultra CPV.

Similar to AES Ultra CPV.

Similar to LMA Classic, but with built-in CPV to minimize postoperative sore throat. Color indicator bands provide instant feedback regarding pressure changes.

The CPV detects changes caused by temperature, nitrous oxide levels, and movement within the airway, enabling clinician to maintain a recommended cuff pressure of 60 cm H2O. Single use.

Reusable, standard SGA.

40 uses.

Wire-reinforced SGA that accommodates repositioning of the head and neck. Color indicator bands provide instant feedback regarding pressure changes.

Single use. The cuff pressure indicator detects changes caused by temperature, nitrous oxide levels, and movement within the airway. The CPV enables the clinician to maintain a recommended cuff pressure of 60 cm H2O.

Reusable, wire-reinforced SGA, designed to accommodate repositioning of the head and neck during surgery.

40 uses.

Enhanced version of the standard air-Q. It is indicated as a primary airway device when an oral endotracheal tube is not necessary or as an aid to intubation in difficult situations.

The soft guide tube allows access to the posterior pharynx and esophagus by supporting and directing medical instruments beneath the air-Q mask and into the pharynx and esophagus.

Medical instruments especially suited are suction catheters, nasogastric tubes up to size 18.0 Fr, and the newly designed air-Q Blocker tubes. The Blocker tubes are designed to suction the pharynx, or suction, vent and block the upper esophagus during use of the air-Q Blocker airway. Removable color-coded connector allows intubation with standard ETs up to 8.5 mm.

Same as air-Q Reusable Laryngeal Mask.

Removable color-coded connector allows intubation with standard ETs up to 8.5 mm.

Similar to both LMA Classic and LMA Fastrach. Allows easy access for flexible fiber-optic devices. Use as routine masked laryngeal airway. Removable connector allows intubation with standard ETs up to 8.5 mm.

Designed to minimize folding of the cuff tip on insertion. Same use and benefits as LMA Classic and LMA Fastrach. Integrated bite block reinforces the tube while diminishing the need for a separate bite block. Color-coded removable connectors are tethered to the airway tube, avoiding episodes of misplaced connectors.

Same as regular air-Q but eliminates the need for mask inflation.

PPV self-pressurizes the mask cuff. On exhalation, mask cuff decompresses to the level of PEEP. Removable connector allows intubation with standard ETs.

Designed for use in ENT, ophthalmic, dental, and torso surgeries.

Integrated pilot tube, and high flexibility enables positioning away from the surgical field, without a loss of seal. Single use. EasyGlide texture and extra-soft cuff ease insertion and removal. Convenient depth marks for monitoring correct position of the mask. table continues on next page

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Table 5. Selected Supraglottic Ventilatory Devices

(continued)

Name (Manufacturer)

Description

Size

Ambu AuraGain (Ambu Inc.)

Second-generation laryngeal mask, featuring an anatomic curve for rapid placement, gastric access for suction and decompression of the stomach via a gastric tube, and integrated direct intubation capability for management of the expected or unexpected difficult airway.

Adult sizes 3-5.

Ambu Aura-i (Ambu Inc.)

Laryngeal mask with built-in curve and bite blocker designed as a conduit for optical endotracheal intubation.

Adult and pediatric sizes 1-6.

Ambu AuraOnce (Ambu Inc.)

A laryngeal mask with a special built-in curve that replicates natural human anatomy. It is molded in 1 piece with an integrated inflation line and no epiglottic bars on the anterior surface of the cuff.

Adult and pediatric sizes 1-6.

Ambu AuraStraight (Ambu Inc.)

Similar to the LMA Unique but without epiglottic bars on the anterior surface of the cuff.

Adult and pediatric sizes 1-6.

Ambu Aura40 (Ambu Inc.)

Same design as the Ambu AuraOnce, but reusable.

Adult and pediatric sizes 1-6.

Ambu Aura40 Straight (Ambu Inc.)

Similar to the LMA Classic. No epiglottic bars on the anterior surface of the cuff.

Adult and pediatric sizes 1-6.

CobraPLA (Pulmodyne)

Large ID laryngeal tube, which is soft and flexible with a tapered, striated tip. Now has an improved distal curve, softer tube, and softer head. It has a high-volume, low-pressure oropharyngeal cuff.

Adult and pediatric sizes ½-6.

CobraPLUS (Pulmodyne)

Similar to the CobraPLA. Includes temperature monitor and distal gas sampling in all sizes.

Adult and pediatric sizes ½-6.

Esophageal Tracheal Combitube (Covidien)

A disposable DLT that combines the features of a conventional ET with those of an esophageal obturator airway. Has a large proximal latex oropharyngeal balloon and a distal esophageal low-pressure cuff with 8 ventilatory holes in between.

Two adult sizes.

41 Fr: height >5 ft.

37 Fr: height 4-6 ft.

i-gel (Intersurgical Inc.)

SGA with a noninflating cuff, designed to mirror the anatomy over the laryngeal inlet, with an integral bite block, buccal cavity stabilizer and a gastric channel. It also incorporates a wide-bore airway channel that can be used as a conduit for intubation with fiber-optic guidance (sizes 3, 4, and 5).

Adult sizes 3-5 and pediatric sizes 1-2.5.

Adult sizes accommodate ET sizes 6.0-8.0 mm.

i-gel O2 Resus Pack (Intersurgical Inc.)

SGA with a supplementary oxygen port, an integral colorcoded hook ring for securing of the airway support strap and identification of size and is designed to facilitate ventilation. It also includes a non-inflating cuff to mirror the anatomy, with an integral bite block, buccal cavity stabilizer and a gastric channel. The pack contains an i-gel O2 second-generation SGA, a sachet of lubricant and an airway support strap.

Adult sizes 3-5.

Adult sizes accommodate ET sizes 6.0–8.0 mm.

KING LT (Ambu Inc.)

Multiuse, latex-free, single-lumen silicone tube with oropharyngeal and esophageal low-pressure cuffs, 2 ventilation outlets, insertion marks, and a blind distal tip (almost like a singlelumen, shortened Combitube). Color-coded connectors for each size.

Sizes 0-5.

KING LT-D (Ambu Inc.)

Same design as the KING LT, except disposable.

Adult sizes 3-5 and pediatric sizes 2, 2.5.

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Clinical Applications

Special Features

Useful for ventilation and intubation. Appropriate for management of the expected or unexpected difficult airway.

Allowable ETT size is designated on each device; gastric access channel allows up to a 14 Fr tube.

Combines everyday routine use of SGA with direct intubation capability in case of difficult airway situations.

Anatomically correct curve designed as Ambu AuraOnce and Ambu Aura40 but specially designed as a conduit for intubation.

Compatible with standard ETs.

Allows easy access for flexible fiber-optic devices. For use in both anesthesia and emergency medicine.

Anatomically correct curve facilitates placement. One-piece mold.

EasyGlide texture for ease of insertion. Convenient depth marks for monitoring correct position of the mask. MRI safe. Extra-soft cuff. If intubation becomes necessary or desired, recommend intubation over Aintree AEC. Single use.

For use in both anesthesia and emergency medicine.

Single-use, one-piece mold. EasyGlide texture for ease of insertion. Convenient depth marks for monitoring correct position of the mask. MRI safe. Extra-soft cuff.

Same as LMA Classic.

Same as LMA Classic, but reusable.

Same as LMA Classic.

Reusable. Available only in the United States.

Same as LMA Classic.

Disposable. If intubation becomes necessary or desired, will accommodate ET up to 8.0 mm. Single use.

Same as LMA Classic. An added benefit is the ability to measure core temperature. In addition, distal CO2 can be monitored in pediatric patients.

Similar to CobraPLA, but CobraPLUS allows monitoring of the patientâ&#x20AC;&#x2122;s core temperature. In neonatal and infant patients, CobraPLUS has the ability to increase the accuracy of end-tidal CO2 and volatile gas analysis. If intubation becomes necessary or desired, will accommodate ET up to 8.0 mm. Single use.

Same as LMA Classic but not contraindicated in non-fasting patients. Appropriate for prehospital, intraoperative, and emergency use. Especially useful for patients in whom direct visualization of the vocal cords is not possible, patients with massive airway bleeding or regurgitation, limited access to the airway, and patients in whom neck movement is contraindicated.

Ventilation is possible with either tracheal or esophageal intubation. Distal cuff seals off the esophagus to prevent aspiration of gastric contents. Allows passage of an oro-gastric tube when placed in the esophagus. Single use.

Indicated for use in routine and emergency anesthesia and resuscitation in adult patients. i-gel is not indicated for use in resuscitation in children. Can be used as a conduit for intubation with fiber-optic guidance (sizes 3, 4, and 5). Gastric channel provides an early warning of regurgitation, allows for the passing of a nasogastric tube to empty the stomach contents and can facilitate venting of gas from the stomach (except size 1).

The non-inflating cuff allows easy and rapid insertion, provides high seal pressures and minimizes the risk for tissue compression.

Gastric channel provides an early warning of regurgitation. Buccal cavity stabilizer reduces the risk for rotation or displacement and the integral bite block prevents occlusion of the airway channel.

The wide-bore airway channel also allows for use as a conduit for intubation with fiber-optic guidance (sizes 3, 4, and 5).

Indicated for use in routine and emergency anesthesia and resuscitation in adult patients. Can be used as a conduit for intubation with fiber-optic guidance. i-gel O2 can also be used for providing supplementary oxygen during postoperative care or patient transfer.

Gastric channel provides an early warning of regurgitation, allows for the passing of a nasogastric tube to empty the stomach contents and can facilitate venting of gas from the stomach.

The non-inflating cuff allows easy and rapid insertion, provides high seal pressure and minimizes the risk for tissue compression.

The supplementary oxygen port allows for the administration of passive oxygenation as a component of cardio-cerebral resuscitation. Gastric channel provides an early warning of regurgitation.

Buccal cavity stabilizer reduces the risk for rotation or displacement and the integral bite block prevents occlusion of the airway channel. The wide-bore airway channel also allows for use as a conduit for intubation with fiber-optic guidance.

Same as LMA Classic, but with ventilatory seal characteristics like those of LMA ProSeal.

Easily inserted, possible aspiration protection, and allows both PPV and spontaneous breathing. Reusable (up to 50 times).

Same as KING LT.

Also available in a kit. Single use. table continues on next page

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Table 5. Selected Supraglottic Ventilatory Devices

(continued)

Name (Manufacturer)

Description

Size

KING LTS (Ambu Inc.)

Double-lumen laryngeal tube that incorporates a second (esophageal) lumen posterior to the ventilation lumen.

Adult sizes 3-5 and pediatric sizes 0, 1, 2, 2.5.

KING LTS-D (Ambu Inc.)

Same as KING LTS, except disposable.

Adult sizes 3-5.

LMA Classic (LMA North America, a Teleflex Company)

Supraglottic ventilatory device that consists of an oval inflatable silicone cuff in continuity with a wide-bore tube that can be connected to an Ambu bag or anesthesia circuit. Designed to fit the pharynx of patients of various weights.

Adult and pediatric sizes 1-6, accommodating ET 3.5-7.0 mm.

LMA Classic Excel (LMA North America, a Teleflex Company)

The Classic Excel has the benefits of LMA Classic and an improved design to facilitate intubation.

Adult and pediatric sizes 3-5.

LMA Fastrach (LMA North America, a Teleflex Company)

Consists of a mask attached to a rigid stainless steel tube curved to align the barrel aperture to the glottic vestibule. The set includes an LMA with a stainless steel shaft covered with silicone (reusable version) and a single movable epiglottic elevating bar, ET stabilizer, and silicone wire-reinforced ET. The single-use Fastrach is made of PVC and includes a disposable wire-reinforced ET.

Adult sizes 3-5 that can accommodate special ETs 6.0-8.0 mm.

LMA Flexible (LMA North America, a Teleflex Company)

Original LMA cuff design attached to smaller diameter, flexible armored tube that allows repositioning of the tube without cuff displacement. New single-use version is easier to insert.

Adult and pediatric sizes 2-6.

LMA ProSeal (LMA North America, a Teleflex Company)

Designed with a modified cuff and dual tubes to separate the respiratory and alimentary tracts. Has a built-in bite block.

Adult and pediatric sizes 1-5.

LMA Supreme (LMA North America, a Teleflex Company)

Has a gastric drain tube designed to suction the stomach, channel gases and fluids away from the airway, and confirm placement of the tip of mask at upper esophageal sphincter.

The airway tube has a gentle curve and oblong shape to allow easier insertion and more stable placement.

Adult and pediatric sizes 1-5.

LMA Unique (LMA North America, a Teleflex Company)

Original, disposable LMA design. Sterile, latex-free, available with or without syringe and lubricant. Soft cuff and airway tube allow for conformity to patients’ natural anatomy.

Adult and pediatric sizes 1-5.

Rüsch Easy Tube (Teleflex Medical)

Disposable LT that combines the features of a conventional ET with those of an esophageal obturator airway similar in design to the Combitube.

Small 28 Fr; large 41 Fr.

Soft-Seal Laryngeal Mask (Smiths Medical)

Similar in shape to the LMA Unique, but differs in its 1-piece design, in which the cuff is softer and there is no “step” between the tube and the cuff, an integrated inflation line, no epiglottic bars on the anterior surface of the cuff, and a wider ventilation orifice.

Adult and pediatric sizes 1-5.

Solus Satin Laryngeal Mask Airway (Intersurgical Inc.)

A range of single-use, latex-free laryngeal mask airways with a softer airway tube to provide more flexibility.

Adult sizes 3-5.

Solus Standard Laryngeal Mask Airway (Intersurgical Inc.)

A range of single-use, latex-free laryngeal mask airways.

Adult sizes 3-5 and pediatric sizes 1-2.5.

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Clinical Applications

Special Features

Same as KING LT, except that it has a second lumen for gastric access, similar to LMA ProSeal.

Allows easy passage of a gastric tube to evacuate stomach contents. Distal tip reduced in size to facilitate insertion. Reusable.

Same as KING LTS.

Allows passage of 18 Fr gastric tube. Also available in a kit.

Although originally developed for airway management of routine cases with spontaneous ventilation, it is now listed in the ASA Difficult Airway Algorithm as an airway ventilatory device or a conduit for endotracheal intubation. Can be used in both pediatric and adult patients in whom ventilation with a face mask or intubation is difficult or impossible. Can also be used as a bridge to extubation and with pressure support or PPV.

Reusable.

Same as LMA Classic.

Removable connector and epiglottic elevating bar to facilitate intubation. Works with ET up to 7.5 mm. Reusable up to 60 times.

Useful for ventilation and intubation. Designed for blind orotracheal intubation but can be used with lighted stylets, FOB, or Flexible Airway Scope Tool. FOB recommended when using PVC ET.

Both reusable and disposable versions now available. Can be utilized as a blind or visually guided technique. Benefits include ability to intubate with larger ET and remove the device easily over the ET.

Particularly useful in ENT/head and neck procedures.

Both reusable and disposable versions now available. Airway tube resists kinking and cuff dislodgment, and thus may be positioned away from the surgical field without loss of seal.

Same as LMA Classic except drain tube also allows for evacuation of stomach contents.

Second cuff allows tighter seal for PPV. Reusable.

Same as LMA ProSeal.

A single-use LMA with a redesigned mask that achieves a 50% higher seal pressure than the Classic or Unique. Similar to all LMAs, the Supreme is designed to protect the airway from epiglottic obstructionâ&#x20AC;&#x201D;in this model with molded fins in the bowl of the mask.

Same as LMA Classic. Included in AHA 2000 Guidelines for CPR and Emergency Medicine Cardiovascular Care.

Single use.

Same as Esophageal Tracheal Combitube.

Similar to Combitube with following differences: single lumen at distal tip, soft latex-free cuff, open proximal second lumen allows use of fiber-optic device or passage of a suction catheter or tube exchanger. Single use.

Same as LMA Classic. Allows easy access for flexible fiber-optic devices.

If intubation becomes necessary or desired, will accommodate ET up to 7.5 mm. Single use.

Indicated for use in anesthesia and emergency medicine. Singleuse laryngeal mask airway, provided sterile and ready for use.

Classic cuff shape for optimum anatomic conformance with a firm, smooth-surfaced back plate to aid ease of insertion. The Satin Solus has a softer airway tube to provide more flexibility. Clear, pliable airway tube allows for early detection of rising fluids. Cuff size indicators are accurately aligned and prominently displayed at top of tube and on pilot balloon. Essential user information on exposed section of airway tube for quick visual reference.

Indicated for use in anesthesia and emergency medicine. Singleuse laryngeal mask airway, provided sterile and ready for use.

Classic cuff shape for optimum anatomic conformance with a firm, smooth-surfaced back plate to aid ease of insertion. Clear, pliable airway tube allows for early detection of rising fluids. Cuff size indicators are accurately aligned and prominently displayed at top of tube and on pilot balloon. Essential user information on exposed section of airway tube for quick visual reference.

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Table 6. Devices for Special Airway Techniques Name (Manufacturer)

Description

Size

DeVilbiss Model 15 Medical Atomizer (DeVilbiss Healthcare)

Metal atomizer; includes glass receptacle (for liquid), pair of metal outlet tubes extending from metal atomizing nozzle, and adjustable tip for directing spray to inaccessible areas of the throat. Can be used with or without RhinoGuard tip cover.

Length: 10.5 in.

Enk Fiberoptic Atomizer Set (Cook Medical)

Device for atomizing small doses of local anesthetics. Atomizer set consists of a pressure-resistant oxygen tube and a connecting tube attached by a 3-way side-arm fitting with a small flow control opening. The set also contains an introducer catheter and 2 syringes (1-mL).

EZ-Spray (Alcove Medical)

Disposable atomizer device which comprises a plastic receptacle, atomizer nozzle, and gas inlet tube. Tubing is connected from an air or oxygen flowmeter nipple to the gas inlet tube on the device.

LMA MADdy Pediatric Mucosal Atomization Device (LMA North America, a Teleflex Company)

Pediatric Mucosal Atomization Device delivers intranasal/ intraoral medications in a fine mist that enhances absorption and improves bioavailability for fast and effective drug delivery.

Typical particle size: 30 microns.

System dead space: 0.12 mL (with syringe), 0.07 mL (device only). Tip diameter: 0.19 in (4.8 mm). Applicator length: 4.5 in (11.4 cm).

LMA MADgicWand Mucosal Atomization Device (LMA North America, a Teleflex Company)

Combines atomized topical anesthesia and oxygen delivery in a fiber-optic oral airway. Packaged in a box of 20.

Typical particle size: 30-100 microns.

System dead space: 0.25 mL.

LMA MADgic Laryngo-Tracheal Atomizer (LMA North America, a Teleflex Company)

Mucosal atomization device that incorporates a small flexible, malleable tube with an internal stiffening stylet that connects to a 3-mL syringe.

Typical particle size: 30-100 microns. System dead space: 0.25 and 0.13 mL. Tip diameter: 0.18 in (4.6 mm). Applicator length: 8.5 in (21.6 cm) and 4.5 in (11.4 cm).

LMA MAD Nasal-Intranasal Mucosal Atomization Device (LMA North America, a Teleflex Company)

Disposable, compact atomizer for delivery of medications to the nose and throat in a fine, gentle mist.

Typical particle size: 30-100 microns.

System dead space: 0.13 and 0.07 mL. Tip diameter: 0.17 in (4.3 mm).

Applicator length: 1.65 in (4.2 cm).

Available as a complete set in 6.0, 11.0, or 14.0 F. 14 F version includes Airway Exchange Catheter with Rapi-Fit adapters to allow for delivery of oxygen.

6.0 F=50 cm; 14.0 F=60 cm, extra stiff floppy tipped guide wire = 110 cm.

Awake Intubation

Retrograde Cook Retrograde Intubation Set (Cook Medical)

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Clinical Applications

Special Features

Intended for the application of topical anesthetics to the nose, oropharynx, and upper airway of patients, at the direction/discretion of a clinician.

Includes glass receptacle for dispensing the liquid; adjustable swivel top and vented nasal guard attached to a hand bulb. Can be used with all types of oil or water solutions that are compatible with rhodium metal plating. The all-metal top can be autoclaved. Reusable.

To apply topical anesthetics to laryngotracheal area through the working channel of a bronchoscope using oxygen flow. Designed and intended to be used by those trained and experienced in techniques of flexible fiberoptic intubation.

Device is an accessory to a bronchoscope. Delivery form is a fine spray mist using oxygen flow through the working channel bronchoscope. Sterile. Single use.

Application of topical anesthetic to the nose, oropharynx, and upper airway of patients, at the direction/discretion of a clinician.

Trigger-valve system provides controlled release of compressed gas to an atomizing nozzle, creating a liquid spray. Gas flow is adjusted to the desired setting. Use with either oil- or water-based solutions.

Nonsterile. Single use.

Application of topical anesthetics to oropharynx and upper airway region. Fits through vocal cords, down LMA, or into nasal cavity.

Child-friendly and no sharps (bright colors in a toy-like presentation make the procedure less scary for young patients). Flexible (internal stylet provides support, malleability and memory). Disposable (single patient use, eliminates risk for cross-contamination). Practitioner-controlled (patient needs targeted specially by medication, concentration, position, and location).

Allows retraction of soft tissue while applying topical anesthesia in a fine, gentle mist. Used to apply topical anesthetic to the airway before awake intubation.

Device blade positioned along floor of the mouth can be directed immediately in front of laryngeal inlet to generate a fine mist by a piston syringe. Nonsterile. Single use.

Application of topical anesthetics to oropharynx and upper airway region. Fits through vocal cords, down LMA, or into nasal cavity.

Malleable applicator retains memory to adapt to individual patient’s anatomy. Delivery of a fine spray mist is generated by a piston syringe. Luer connection adapts to any luer lock syringe. Nonsterile.

Single use.

Intranasal medication delivery offers a rapidly effective method to deliver selected medications to a patient without the need for a painful shot and without the delays in onset seen with oral medications.

Rapidly effective (atomized nasal medications absorb directly into blood stream, avoiding first-pass metabolism; atomized nasal medications absorb directly into the brain and cerebrospinal fluid via olfactory mucosa to nose–brain pathway, achieves medication levels comparable to injections). Controlled administration (exact dosing, exact volume, titratable to effect [repeat if needed], atomizes in any position, atomized particles are optimal size for deposition across broad area of mucosa).

Technique used for securing a difficult airway, either alone or with other alternative airway techniques. Especially useful in patients with limited neck mobility or patients who have suffered airway trauma. 6.0 Fr places tubes ≥2.5 mm ID; 14.0 Fr places tubes ≥5.0 mm ID.

Packaged as a complete kit with everything needed to perform a retrograde intubation. The recently added Arndt Airway Exchange Catheter allows for patient oxygenation and facilitates placement of an ET. Disposable.

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Table 6. Devices for Special Airway Techniques Name (Manufacturer)

(continued)

Description

Size

Boussignac CPAP System (LMA North America, a Teleflex Company)

Open CPAP with an integral pressure-relief system. The CPAP device has 2 ports: a green one with integral oxygen connecting tube, and a colorless port for controlling pressure, monitoring CO2, and adding oxygen.

Small, small adult, medium adult, and large adult.

Endoscopy Mask (VBM Medizintechnik GmbH)

Face mask with diaphragm to allow simultaneous ventilation and endoscopy.

Newborn, infant, child, and adult.

Flow-Safe II CPAP System (Mercury Medical)

Disposable CPAP with deluxe mask and comfortable head harness, color-coded manometer for verifying CPAP pressure and pressure-relief system. Flow-Safe II works with standard flowmeters that can deliver over 10 cm H2O at 15 LPM. Accepts standard nebulizers and standard CO2 sampling lines.

Child, small adult, and large adult.

Flow-Safe II EZ CPAP System (Mercury Medical)

Disposable CPAP similar to Flow-Safe II that also includes an integrated nebulizer. The system requires only one oxygen source to run both the CPAP and nebulizer devices. CPAP system includes color-coded manometer for verifying CPAP pressure and pressure-relief system. Flow-Safe II EZ works with standard flowmeters that can deliver over 10 cm H2O at 15 LPM. Higher flow pressures may be necessary when running both CPAP and the nebulizer.

Child, small adult, and large adult.

AincA Manual Jet Ventilator (Anesthesia Associates, Inc.)

Portable jet ventilation device with thumb depression mechanism that initiates a controlled burst of oxygen flow. Customizable assembly includes DISS inlet connection, 5 ft of inlet tubing, flow control knob, on/off thumb control, internal filter, back pressure gauge, and 2 ft of outlet hose ending in a Luer-Lok male fitting. Connects to any tool or port that has a Luer-Lok female connection (ie, malleable stylets, various adapters, etc).

Jet ventilation catheters of malleable copper with Luer fittings accommodate adults, children, and infants.

Adapters allow direct connection to bronchoscope or ET.

AincA MRI Conditional 3.0 Tesla Manual Jet Ventilator (Anesthesia Associates, Inc.)

Similar to AincA Manual Jet Ventilator but certified MRI Conditional窶田ompatible for use in units up to 3.0 Tesla strength.

Jet ventilation catheters of malleable copper with Luer fittings accommodate adults, children, and infants.

MRI Conditional 3.0 Tesla.

Enk Oxygen Flow Modulator Set (Cook Medical)

Complete set including 15-gauge needle with reinforced fluorinated ethylene propylene catheter, syringe (5 cc), connecting tubing, and Enk oxygen flow modulator with tracheal catheter connector.

7.5 cm (2.0 mm ID).

Manual Jet Ventilator (Instrumentation Industries)

Complete set includes an on/off valve, 6 ft of high-pressure tubing, and 4 ft of small-bore tubing.

Jet ventilation catheter size 13G can accommodate adults, and 14G children.

Manujet III (VBM Medizintechnik GmbH)

Complete set including 13 ft high-pressure hose assembly with oxygen DISS fittings, 40-degree small bore tube assembly (with luer lock fitting) and 3 jet ventilation catheters (13G, 14G, and 16G).

Jet ventilation catheters can accommodate adults, children, and infants.

Face Mask Ventilation

Transtracheal Jet Ventilation

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Clinical Applications

Special Features

Provides respiratory assistance to patients breathing spontaneously. Effective postoperatively in obese patients with sleep apnea.

Compatible with all face masks, ETs, and tracheostomy tubes. Mask head harness is designed for patient comfort.

• • • •

Available in different sizes and with different sizes of diaphragms for a perfect seal during endoscopy. Special Bronchoscope Airway available to protect equipment and aid endoscopy.

Fiber-optic intubation Airway endoscopy Gastroenterology Transesophageal echocardiography

Manual Jet Ventilation for oxygen saturation maintenance and usable for emergency direct TTJV and for laser throat surgery (elimination of plastic ET in laser path).

Easy factory customization available for hose lengths and oxygen source connection type (DISS vs various quick-disconnect types) as well as optional pressure regulator (with gauge) and standard or custom regulator-to-source connection hoses. Adapters, fittings, and connectors available. Completely reusable and sterilizable.

Similar to the AincA Manual Jet Ventilator, but fully certified for use in MRI suites with coil strength to 3.0 Tesla.

Allows emergency oxygen saturation maintenance while determining how to solve airway issues.

Easy factory customization available for hose lengths and oxygen source connection type (DISS vs various quick-disconnect types).

Adapters, fittings, and connectors available. Completely reusable and sterilizable.

Similar to the AincA Manual Jet Ventilator. Recommended for use when jet ventilation is appropriate but a jet ventilator is unavailable.

Packaged as a complete set with everything needed to perform TTJV. Disposable.

Same as Manujet III. Can also be used in unobstructed difficult airway management.

Offered with and without an adjustable pressure regulator. Partially reusable outlet tube is disposable.

NOTE: Outlet tube is single-use.

Well-accepted method for securing ventilation in rigid and interventional bronchoscopy. Because airflow is generally unidirectional, it is important that air has a route to escape (unobstructed airway).

Packaged as a complete kit with jet ventilation catheters to perform TTJV. Includes gauge and regulator.

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Table 7. Positioning Devices Name (Manufacturer)

Description

Chin-UP (Dupaco Inc.; distributed by Mercury Medical)

Hands-free airway support device used to lift up the patientâ&#x20AC;&#x2122;s chin and hold it in position to keep the airway open.

Face-Cradle (Mercury Medical)

Fully adjustable cushion set accommodates most adult head sizes.

JED Jaw Elevation Device (Hypnoz Therapeutic Devices; distributed by LMA North America, Inc., a Teleflex Company)

Hands-free, noninvasive device that helps clinicians maintain an open airway during any procedure in which a patient is sedated and the airway may be compromised.

RAMP Rapid Airway Management Positioner (Airpal Patient Transfer Systems, Inc.)

Air-assisted medical device that can be inflated to transfer and position patients for various procedures.

Troop Elevation Pillow (Mercury Medical)

Foam positioning device that quickly achieves the headelevated laryngoscopy position (HELP). Includes many accessories (head cradle, arm board pads, additional pillow).

Table 8. Cricothyrotomy Devices Name (Manufacturer)

Description

Size

6 Fr reinforced fluorinated ethylene propylene catheter.

5.0 and 7.5 cm.

Melker Emergency Cricothyrotomy Catheter Set (Cook Medical)

Complete set including syringe (10 cc), 2- to 18-gauge introducer needles with TFE catheter (short and long), 0.038-in diameter Amplatz extra-stiff guidewire with flexible tip, scalpel, curved dilator with radiopaque stripe, and PVC airway catheter.

Also available in a Special Operations kit, which includes all of the above in a slip peel-pouch and 2 airway catheters.

Standard kit: 3.8 cm (3.5 mm ID), 4.2 cm (4.0 mm ID), and 7.5 cm (6.0 mm ID). Special kit: 4.2 and 7.5 cm.

Pertrach Emergency Cricothyrotomy Kit (Pulmodyne)

Contents include 2 splitting needles, cuffed or uncuffed Trach tube, dilator with flexible leader, twill tape, syringe, extension tube, and scalpel (optional).

Adult: 6.8 cm (5.6 mm ID).

Child: 3.9 cm (3.0 mm ID), 4.0 cm (3.5 mm ID), 4.1 cm (4.0 mm ID), and 4.4 cm (5.0 mm ID).

Quicktrach Emergency Cricothyrotomy Device (VBM Medizintechnik GmbH)

Complete kit includes airway catheter, stopper, needle, and syringes that come preassembled.

Adult (4.0 mm ID) and child (2.0 mm ID).

Needle Cricothyrotomy Emergency Transtracheal Airway Catheter (Cook Medical) Percutaneous Cricothyrotomy

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Clinical Applications

Special Features

Aids during monitored anesthesia care and total intravenous anesthesia sedation procedures.

Disposable polyurethane foam cushions.

For use in prone-position surgeries.

OR procedures, MRI, recovery, FOB intubation, and interventional radiology, oral surgery, and endoscopy procedures.

Assists provider in maintaining an open airway in sedated or anesthetized patients without the need for additional instrumentation.

Frees medical personnel from the need to hold the jaw manually in sedated patients. When left in place after a procedure, reduces postoperative airway complications. Noninvasive and easy to use.

Reusable device with disposable pads.

Allows for the positioning of a patient for direct laryngoscopy, extubation, and central venous access. Enhances the safe apnea period, bag valve mask ventilation, and chest wall excursion.

Base of the RAMP is integrated with an Airpal platform (air-assisted lateral patient transfer and positioning device). Inflates and deflates, thus can remain in place during surgery and reinflate for extubation.

Reusable.

Aids airway management for obese patients by aligning upper airway axes, and facilitating mask ventilation, laryngoscopy, direct laryngoscopy, and central venous access.

Allows patients to breathe more comfortably during preoxygenation and regional anesthesia.

Available in disposable and reusable formats. Troop Elevation Pillow may be added for super morbidly obese patients.

Clinical Applications

Special Features

A lifesaving procedure that is the final option for “cannot-ventilate, cannot-intubate” patients in all airway algorithms.

Designed to be kink-resistant specifically for the purpose of needle cricothyrotomy.

Same as Emergency Transtracheal Airway Catheter. Intended to be used with the Seldinger technique via the cricothyroid membrane; however, it has the capability to be used as a surgical cricothyrotomy.

Packaged as a complete kit with everything needed to perform a percutaneous cricothyrotomy. The Special Operations kit comes in a slip peel-pouch for easy transport to offsite locations.

Also can be used in the OR. It comes with 2 differently sized airway catheters to reduce the number of kits needed in the field.

Disposable.

Use in failed orotracheal or nasotracheal intubation and/or fiber-optic bronchoscopy. Immediate airway control in patients with maxillofacial, cervical spine, head, neck, and multiple trauma. Also used when endotracheal intubation is impossible and/or contraindicated. Immediate relief of upper airway block.

Serves as an emergency cricothyrotomy or tracheostomy device that uses a patented splitting needle and dilator to perform a rapid and simple procedure.

Same as Melker Emergency Cricothyrotomy Catheter Set.

Packaged as a complete kit with everything needed to perform a percutaneous cricothyrotomy—even the neck tape and connecting tube. The removable stopper is used to prevent a “too-deep” insertion and avoid the possibility of perforating the rear tracheal wall. The conical needle tip allows for the smallest necessary stoma and reduces the risk for bleeding. Easily transported to offsite locations. Disposable. table continues on next page

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Table 8. Cricothyrotomy Devices Name (Manufacturer)

(continued)

Description

Size

Melker Surgical Cricothyrotomy Set (Cook Medical)

Cuffed cricothyrotomy tube, scalpel, tracheal hook Trousseau dilator, and blunt curved dilator in compact package for convenient storage.

9.0 cm (5 mm ID).

Melker Universal Emergency Cricothyrotomy Catheter Set (Cook Medical)

Same as Melker Cuffed Emergency Cricothyrotomy Catheter Set for percutaneous technique. Also includes for surgical technique: tracheal hook, safety scalpel, Trousseau dilator, and blunt curved dilator.

9.0 cm (5.0 mm ID).

Surgicric 1 (VBM Medizintechnik GmbH)

Surgical cricothyrotomy.

6.0 mm ID.

Surgical Cricothyrotomy

Table 9. Tracheostomy Devices Name (Manufacturer)

Description

Size

Percutaneous Dilatational Tracheostomy Ciaglia Blue Dolphin Balloon Percutaneous Tracheostomy Introducer (Cook Medical)

Complete kit with size-specific Blue Dolphin balloon dilator. Available with or without Shiley 6 or 8 PERC tracheostomy tubes.

A tray version is available that includes lidocaine/epinephrine, 15-mm swivel connector, chlorhexidine skin prep, drape, and suture.

21, 24, 26, 27, 28, 30 Fr introducers.

Ciaglia Blue Rhino Percutaneous Introducer Set (Cook Medical)

Complete kit includes 24.0, 26.0, and 28.0 Fr loading dilators and Shiley 6 or 8 PERC disposable dual-cannula tracheostomy tube. A tray version is available that includes lidocaine/epinephrine, connector, chlorhexidine skin prep, drape, needle driver, and suture.

74 mm (6.4 mm ID); 79 mm (7.6 mm ID).

Portex Ultraperc Percutaneous Dilatational Tracheostomy Kit (Smiths Medical)

Complete set with or without a tracheostomy tube.

70.0 mm (7.0 mm ID); 5.5 mm (8.0 mm ID); 81.0 mm (9.0 mm ID).

Weinmann Tracheostomy Exchange Set (Cook Medical)

Includes Cook Airway Exchange Catheter, Tracheostomy loading dilators, and a Blue Rhino dilator for re-dilation if necessary.

For use with tracheostomy tubes as follows: 74 mm (6.4 mm ID); 79 mm (7.6 mm ID).

Shiley TracheoSoft XLT Extended-Length Tracheostomy Tubes (Covidien)

Available in 4 ISO sizes (5.0, 6.0, 7.0, and 8.0 mm ID). Each size offers the choice of cuffed or uncuffed stylets, and proximal or distal extensions. Disposable inner cannula; replacements sold in packages of 10.

90 mm (5.0 mm ID); 95 mm (6.0 mm ID); 100 mm (7.0 mm ID); 105 mm (8.0 mm ID).

Surgical Tracheostomy Surgical tracheostomies are performed by making a curvilinear skin incision along relaxed skin tension lines between sternal notch and cricoid cartilage. A midline vertical incision is then made dividing strap muscles, and division of thyroid isthmus between ligatures is performed. Next, a cricoid hook is used to elevate the cricoid. An inferior-based flap or Bjork flap (through second and third tracheal rings) is commonly used. The flap is then sutured to the inferior skin margin. Alternatives include a vertical tracheal incision (pediatric) or excision of an ellipse of anterior tracheal wall. Finally, the tracheostomy tube is inserted, the cuff is inflated, and it is secured with tape around the neck or stay sutures.

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Clinical Applications

Special Features

This set provides the tools that clinicians can use if they prefer a surgical approach to performing emergency cricothyrotomy.

Complete and convenient packaging.

Same as Melker Emergency Cricothyrotomy Catheter Set.

One-half of the tray is the same as Melker Cuffed Emergency Cricothyrotomy Catheter Set for the percutaneous technique. The other half of the tray includes all items needed to perform a surgical emergency cricothyrotomy.

Surgical cricothyrotomy according to the Rapid Four-Step Technique. A lifesaving procedure that is the final option for “cannotventilate, cannot-intubate” situations.

Complete kit including scalpel, tracheal hook, dilator, cuffed tracheal tube, fixation and extension tubing.

Clinical Applications

Special Features

One-step dilation and tracheal tube insertion. Establishes transcutaneous access to the trachea below the level of the cricoid cartilage by Seldinger technique.

Unique balloon-tipped design dilatation and tracheal tube insertion in one step. Packaged as a complete kit with everything needed to perform a percutaneous dilatational tracheostomy.

Same as Portex Ultraperc Percutaneous Dilatational Tracheostomy Kit.

Packaged as a complete kit with everything needed to perform a percutaneous dilatational tracheostomy. The single dilator with a hydrophilic coating and flexible tip results in a simpler, less traumatic insertion. The wire guide has a Safe-T-J tip to reduce trauma. Disposable.

Establishes transcutaneous access to the trachea below the level of cricoid cartilage. Allows for smooth insertion of the tracheostomy tube over a Seldinger wire.

Packaged as a complete kit with everything needed to perform a percutaneous dilatational tracheostomy. The dilator is singlestaged and prelubricated with an ergonomic handle to facilitate insertion. Disposable.

This set is used to facilitate exchange of adult tracheostomy tubes allowing for stomal redilation if required.

This is the only device available that provides an airway exchange catheter to maintain stomal access and that also allows redilation of stoma if resistance is met.

Flexible dual cannula tube for patients with unusual anatomy. Proximal length extension for thick necks; distal length extension for long necks, tracheal stenosis, or malacia.

The only fixed-flange extended-length tube with disposable inner cannula. Flexible inner cannula conforms to the shape of the outer cannula. Sixteen configurations to fit a wide variety of patients. Disposable.

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Recommended Reading 1.

American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway.

Anesthesiology. 2003;98(5):1269-1277.

2. Miller CG. Management of the difficult intubation in closed malpractice claims. ASA Newsletter. 2000;64(6):13-19.

3. Davis L, Cook-Sather SD, Schreiner MS. Lighted stylet tracheal intubation: a review. Anesth Analg. 2000;90(3):745-756.

4. Frass M, Kofler J, Thalhammer F, et al. Clinical evaluation of a new visualized endotracheal tube (VETT). Anesthesiology.

1997;87(5):1262-1263.

5. Tuckey JP, Cook TM, Render CA. Forum. An evaluation of the levering laryngoscope. Anaesthesia. 1996;51(1):71-73.

6. Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anesth. 2003;50(6):611-613.

7. Agro F, Barzoi G, Montecchia F. Tracheal intubation using a Macintosh laryngoscope or a GlideScope in 15 patients with cervical spine immobilization (letter). Br J Anaesth. 2003;90(5):705-706.

8. Gorback MS. Management of the challenging airway with the Bullard laryngoscope. J Clin Anesth. 1991;3(6):473-477.

9. Bjoraker DG. The Bullard intubating laryngoscopes. Anesthesiol Rev. 1990;17(5):64-70.

10. Wu TL, Chou HC. A new laryngoscope: the combination intubating device. Anesthesiology. 1994;81(4):1085-1087.

11. Verghese C. Airway management. Curr Opin Anaesthesiol.

1999;12(6):667-674.

12. Benumof JL. Laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology. 1996;84(3):686-699.

13. Patel P, Verghese C. Delayed extubation facilitated with the use of a laryngeal mask airway in the intensive care unit. Anaesthesia.

2000;55(4):396.

14. Brimacombe J, Keller C, Hörmann C. Pressure support ventilation versus continuous positive airway pressure with the laryngeal

mask airway: a randomised, crossover study of anesthetized adult patients. Anesthesiology. 2000;92(6):1621-1623.

15. Dörges V, Ocker H, Wenzel V, Schmucker P. The laryngeal tube: a new simple airway device. Anesth Analg. 2000;90(5):1220-1222.

16. Gaitini LA, Vaida SJ, Somri M, Tome R, Yanovski B. A comparison of the Cobra, Perilaryngeal Airway, and Laryngeal Mask Airway Unique in spontaneously breathing adult patients. Anesthesiology.

2004;101:A518.

17. Gupta B, McDonald JS, Brooks JH, Mendenhall J. Oral fiberoptic intubation over a retrograde guidewire. Anesth Analg.

1989;68(4):517-519.

18. Sivarajan M, Stoler E, Kil HK, Bishop MJ. Jet ventilation using fiberoptic bronchoscopes. Anesth Analg. 1995;80(2):384-387.

19. Audenaert SM, Montgomery CL, Stone B, Akins RE, Lock RL. Retrograde-assisted fiberoptic tracheal intubation in children with difficult airways. Anesth Analg. 1991;73(5):660-664.

20. Klain M, Smith RB. High-frequency percutaneous transtracheal jet ventilation. Crit Care Med. 1977;5(6):280-287.

21. Enk D, Busse H, Meissner A, Van Aken H. A new device for oxygenation and drug administration by transtracheal jet ventilation.

Anesth Analg. 1998;86:S203.

22. Safar P, Penninckx J. Cricothyroid membrane puncture with special cannula. Anesthesiology. 1967;28(5):943-948.

23. Safar P, Bircher NG. Cardiopulmonary Cerebral Resuscitation. 3rd ed.

London, England: WB Saunders; 1988.

24. Wong EK, Bradrick JP. Surgical approaches to airway management for anesthesia practitioners. In: Hagberg CA, ed. Handbook of Difficult Airway Management. Philadelphia, PA: Churchill Livingstone; 2000:209-210.

25. Gibbs M, Walls R. Surgical airway. In: Hagberg CA, ed. Benumof’s Airway Management. 2nd ed. Philadelphia, PA: Mosby Elsevier; 2007:678-696.

26. Sarpellon M, Marson F, Nani R, Chiarini L, Bradariolo S, Fonzari C. Translaryngeal tracheostomy (TLT): a variant technique for use in hypoxemic conditions and in the difficult airway [in Italian]. Minerva Anestesiol. 1998;64(9):393-397.

Abbreviation Key AEC airway exchange catheter AHA American Heart Association ASA American Society of Anesthesiologists CCD charge-coupled device CMOS complementary metal oxide semiconductor CPAP continuous positive airway pressure CPR cardiopulmonary resuscitation DCI direct coupled interface DISS diameter index safety system DL direct laryngoscopy DLT double-lumen tube ED emergency department EF extra firm EMS emergency medical services ENT ear nose and throat ET endotracheal tube FOB fiber-optic bronchoscope Fr French ICU intensive care unit ID internal diameter ILMA intubating laryngeal mask airway

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ISO LCD LED LMA LT LTA MAC NICU NTSC OD OR PEEP PPV PVC PVP SGA Stat TFE TTJV USB VL

International Organization for Standardization liquid crystal display light-emitting diode laryngeal mask airway laryngeal tube laryngeal tracheal anesthesia Macintosh neonatal intensive care unit National Television System Committee outer diameter operating room positive end-expiratory pressure positive pressure ventilation polyvinyl chloride polyvinylpyrrolidone supraglottic airway sterile single-use blade tetrafluoroethylene transtracheal jet ventilation universal serial bus video laryngoscopy

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Cost Accounting In the Operating Room: Assessing Value KRISTEN TELISCHAK, MD, CPA Clinical Instructor Stanford School of Medicine Stanford University Stanford, California The author reports no relevant financial conflicts of interest.

S

tudying cost in the operating room is by no means a new endeavor. However, with the

paradigm shifting from “fee for service” to the “accountable care organization” (ACO) model, our hospital systems are faced inevitably with major adjustments to their payment system.

We as physician-anesthesiologists must consider what our future roles might entail to help succeed with these transitions. We cannot deny the need for accurate cost measurement and outcomes assessment. To this end, we must first understand the basics of hospital cost accounting systems and then seek to understand where opportunity lies for improvement.

A Historical Perspective By 1948, Blue Cross and Blue Shield (BCBS) accounted for approximately 9% of total hospital expenses.1 By 1958, this percentage had grown to 27%, with nearly one-third of the US population enrolled in BCBS. At that time, BCBS paid the average cost of a day of care plus a small supplemental amount. This arrangement helped keep administrative overhead costs in check. However, in the 1950s, alternative health insurance products called indemnity policies were born, forcing patients to pay a copay and a deductible directly to the hospital.1 This became known as today’s fee-for-service model, which placed a new collection burden on hospitals, and fees often proved difficult and even impossible to collect.1 Hospitals, in turn, hired additional administrative staff to improve their collections, which meant a considerable additional expense for the hospital. To compensate for these uncollectible expenses, hospitals began to require indemnity products to pay higher rates, introducing the notion of billed charges.

In the 1960s, the development of managed care programs further advanced the third-party payment system. Both Medicare and Medicaid also initially paid on a per-diem basis; it was not

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until 1983 that the prospective payment system (PPS) was enacted. This brought about privately negotiated rates based on inflated charges to third-party payors and legislated government rates for the managed care programs.1 The goal of managed care was still to reimburse the hospitals at their cost. This became increasingly difficult as the billed charges soared and health care expenditures rose at rates exceeding inflation. At that time, the Medicare spending cap was introduced in an attempt to tie health care growth to the inflation rate.1 It is not surprising that much confusion exists among health care professionals regarding what defines cost.

Those who study hospital cost accounting, such as Harvard Business School’s Robert Kaplan and Michael Porter, have long advocated that we should look beyond such distractions as the aging population, new treatments, and various perverse incentives to a more fundamental source of escalating costs, namely the system by which our costs are measured and the lack of understanding of how much it actually costs to deliver patient care.2 Even hospital administrators do not agree on the best cost accounting methods to determine the costs for their services. This review addresses the cost accounting methods used by hospitals today and their respective pros and cons. The method is generally determined by the availability of patient-level cost data.3

Traditional Methods Traditional cost accounting methods are analogous to a manufacturing process reflecting the average daily cost rates representative of an average hospitalization, irrespective of that patient’s particular case. This is also known as cost per weighted case. Although the costs are often averaged within a department for a specific procedure, they do not take into account any case variability of a specific patient’s treatment course. The obvious problem with this type of cost accounting is that patients are unique and their hospital courses are extremely variable within a department and the institution. The more variability there is to a procedure, the less appropriate this method will be. The obvious advantage of this method is its low cost and ease of implementation. Proponents might argue that knowing the actual cost of providing services is cumbersome and expensive to implement, and therefore using a traditional charge-based cost accounting system is reasonable.

TOP-DOWN APPROACH Generally, traditional per-diem cost methods have been supplanted by a top-down, transitional, or bottom-up, activity-based costing approach.

The top-down costing system is still used in several hospitals in the United States and Canada, as well as England and France.4 In this method, the aggregate costs to perform a given procedure are tallied and then allocated to individual operations on some type of work-unit basis.3 The work-unit basis might be called the ratio of cost to charge (RCC, in the US) or the relative cost index (RCI, in France). Essentially, the concept

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is the same in both, although the work-unit basis is defined differently. The obvious problem here is that the top-down micro-costing approach relies heavily on its work unit (ie, RCC or RCI) that is determined by aggregate information and not the actual procedure. Similar to the traditional approach, this method is based on aggregate information and may not accurately reflect a particular procedure. Although likely more accurate than the traditional method given its attention to the work-unit basis, it does not consider how internal and external factors may not maintain a constant relationship with costs; it also does not account for resource consumption occurring at the individual patient level.3

TRANSITIONAL COST-BASED ACCOUNTING SYSTEM Hospital cost accounting software systems have begun to integrate multiple hospital information systems to provide relevant cost data. Commercially available cost accounting systems extract clinical data from the medical record and transfer them into a transition system data warehouse, where they can then be integrated with clinical and resource utilization information as well as cost data.4 Generally, a transition cost accounting system organizes hospital activity into three stages4: First, procedures and services are grouped into intermediate products; then the products are grouped to produce individual patient cases; finally, patient cases are aggregated to form groups of common characteristics such as clinical diagnoses or an event, such as postanesthesia care unit time.

Azoulay et al describe transition system methodology as a 6-step process.4 In the first step, hospital departments are categorized into direct and indirect cost centers (Figure). Direct cost centers are those that can be specifically attributed to patient care. Indirect cost centers are a hospital’s overhead costs, such as for administration, housekeeping, and information technology.

Next, intermediate products are formed by grouping services in the direct cost centers, such as nursing care, supplies, or some combination of services, to make an “intermediary product.” Note that at this stage, hospital and department managers have complete discretion as to what the intermediary products are. The closer these products mirror the activities recorded in patient records, the more accurate the costing will be. Hospitals often use their billing systems to identify intermediate products.

In the third step, the relative direct costs of each department’s intermediary products are derived. These are further classified, when possible, as fixed or variable. To derive these direct costs, a method relying on relative value units (RVUs) is used, weighting each intermediary product. This is not the RVU in the traditional sense, with which physicians are familiar. This RVU represents an intermediate product’s consumption of equipment, supplies, and personnel time. It only represents the cost relative to another product within that department. RVUs can be calculated based on national

standards or specific to an institution using actual cost data. Once a department has allocated all intermediate products with RVUs, the total direct costs divided by the total RVUs yields the price per RVU. For example, if there are 100 RVUs and direct costs are $20,000 and indirect costs are $10,000, then a procedure worth 3 RVUs will cost $900, for which $600 are direct costs and $200 are indirect costs.4 In the fourth step of the transition method, the indirect costs are allocated to direct, patient-care cost centers. In this step, application rates must be adopted for each cost center. In this step, cost pools and a base for allocation are predetermined, and then an application rate is applied. This may prove to be a time-consuming and complicated process. One example of this might be allocating housekeeping charges on the basis of department square footage.

In the fifth step, indirect cost centers are further allocated, often using a step-down algorithm. The indirect cost centers or services are ranked in descending amount of service to other departments. The stepdown aspect of this step assumes a one-way relationship of departments. Once a cost center is closed, it can no longer accept costs of other departments. Alternatively, if there are reciprocal services between departments, this step-down method may prove inaccurate, and a reciprocal allocation method may be employed instead.

In the sixth and final step, the indirect costs that were assigned to the direct patient-care cost centers are allocated within each department to intermediary products according to the weighted RVU system. First, the price per RVU is generated using the total indirect costs to allocate, and then the weighting is applied to determine the indirect cost per intermediate product.

One must be aware that bias in this system can have a significant effect on the cost. Both when the

Indirect Cost Centers

Information Technology

intermediate products and when the RVUs are assigned, there are opportunities for managerial bias to occur.

In classifying intermediate products, for instance, one might assume that 80% of the costs are generated by 20% of the procedures (or intermediate products) in order to group products into fewer cost centers. This tremendously decreases the amount of work for cost allocation; however, one must be wary of inaccuracies when using fewer cost centers. How intermediary products are grouped also has a significant effect on the ultimate cost. Finally, the RVUs assigned to intermediate products are subject to bias as well, and the more variability within a type of procedure, the less accurate the cost of this service will be.

BOTTOM-UP APPROACH: ACTIVITY-BASED COST ACCOUNTING Activity-based costing (ABC) is a well-known microcosting method that has been used in the service sector since the 1980s.3 ABC aims to establish the actual amount of specific resources that contribute to each service.3 In reference to work done by Kaplan and others, Young and Pearlman describe the system as follows5: â&#x20AC;&#x153;Under activity-based costing, as it has been developed in the manufacturing sector, accountants trace overhead costs to the products by the activity that links them to the final product. As a result, they measure each activity by the degree to which it adds value to the product during the manufacturing process.

By assigning costs to products based on the type of activity that caused the cost to exist, ABC effectively is a refinement of traditional methods of overhead allocation. The successful design of an ABC system depends largely upon an increase in the number of overhead pools to make each as homogeneous as possible and identifying the cost driver for each.â&#x20AC;?

Human Resources

Finance

Allocated using statistics

Direct Cost Centers

Operating Room

Intensive Care Unit

Allocated using RVUs

OR Activity Code 1

Figure.

OR Activity Code 2

OR Activity Code 3

ICU Activity Code 1

ICU Activity Code 2

Transitional cost accounting system.

RVU, relative value unit

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ABC is now being used to price surgical services by measuring expense at the patient-care level and working upward. Implementation of the ABC model follows these standard steps: mapping activities, calculating the cost of each activity, and calculating the unit cost for each procedure.3 Kaplan and Porter take this approach a step further and apply a time component to each activity, to provide further accuracy to an individual patient encounter. Their approach, known as time-driven activity-based costing, is being trialed at several institutions in the United States. One must understand that even if this approach proves to be the most accurate, it is still complex and requires tremendous resources for implementation.

Kaplan and Porter propose that savings will happen once accurate “value-creating” opportunities are achieved, and then only as a result of spending reduction in non–value-added areas (ie, excess space, supplies, personnel, and equipment).2 They advocate that using forecasts along with process maps for treating patient conditions can supplant the extensive budgeting process that health care organizations face every year.2 Lastly, they add that practically all costs can become “variable” in this system.

Why Methods Matter

granularity than ever before. While debate continues on whether the implementation of the EMR will actually save our health care system, or even save us money, one thing is certain: It provides the opportunity to examine more metrics and outcomes than ever before. Now, assuming that our hospitals have appropriate cost accounting systems in place, we can examine outcomes with respect to the cost of our services.

This means that accurate costing data are imperative to the overall goal of containing costs and improving quality. With an understanding of a hospital cost accounting system, we can begin to understand the cost impacts of our clinical decisions and generate the clinical pathways that are the most cost-effective with the best outcomes.

UNDERSTAND

VALUE IN THE

ACO

MODEL

Cost basis will prove to be an important component of the ACO model. Hospital administrators are beginning to engage in improving cost accounting practices and even offering cost transparency for providers. Some believe that the ACOs will encourage further transition to bundled payments for diagnosis-related groups, or DRGs. When this occurs, we as anesthesiologists must be equipped with an understanding of the costs of the system and the value we provide.

THE SYSTEMS MAY GENERATE VASTLY DIFFERENT COST ESTIMATES Beyond patient, provider, and procedural variability, costing methods add another layer of opportunity for cost variability. Surgical care has been shown to exhibit the lowest agreement between top-down and bottomup estimates.3

SURGERY

IS EXPENSIVE

The Healthcare Cost and Utilization Project (known as H-CUP) reports that approximately 15 million hospital stays each year involve an operating room (OR) procedure and these hospital stays are 2.5 times more expensive than admissions without an OR procedure.6 The OR is a significant cost center and revenue generator of the hospital. The majority of costs associated with surgery are incurred on the day of surgery. We as physiciananesthesiologists have a need for an accurate understanding of the accounting process if we are going to position ourselves as leaders in the perioperative home.

There is extensive opportunity for OR systems improvement—to increase cost transparency to physicians, to identify potential cost savings, and to learn from our more efficient cases.

OPPORTUNITY

TO STUDY OUTCOMES WITH ACCURATE COST

INFORMATION

The incentives have been captured and implementation of electronic medical record (EMR) systems across the country has granted our institutions access to big data, providing us a tremendous opportunity to assess outcomes and compare costs with greater

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Conclusion Technological advances notwithstanding, it is not surprising that since 1960, the proportion of the Gross Domestic Product spent on health care in the United States has grown from 5.3% to more than 18%.1 What is surprising is that with all the growth, discovery, and expense in the health care sector, we lack uniformity and transparency in hospital cost accounting systems.

Experts in the field of hospital accounting agree that there is much we can learn from better understanding our costs. Some argue that accurately measuring costs and outcomes is the single best tool we have to make the bold, and potentially politically difficult, decisions to reduce costs while sustaining good outcomes.2

References 1.

Tompkins CP, Altman SH, Eilat E. The precarious pricing system for hospital services. Health Aff (Millwood), 2006;25:45-56.

2. Kaplan RS, Porter ME. How to Solve The Cost Crisis In Health Care.

Harvard Business Review. 2011; September:47-64.

3. Mercier G, Naro G. Costing hospital surgery services: the method matters. PLoS One 2014;9:e97290.

4. Azoulay A, Doris NM, Filion KB, et al. The use of the transition cost accounting system in health services research. Cost Eff Resour Alloc 2007;5:11.

5. Young DW, Pearlman LK. Managing the stages of hospital cost accounting. Healthc Financ Manage 1993;47:58-64.

6. Weiss AJ, Elixhauser A, Andrews RM. Characteristics of Operating Room Procedures in U.S. Hospitals, 2011. HCUP Statistical Brief #170. February 2014. Agency for Healthcare Research and Quality, Rockville, MD.

PRINTER-FRIENDLY VERSION AVAILABLE AT ANESTHESIOLOGYNEWS.COM

Ultrasound-Guided Cervical Nerve Root Injections: Safety and Outcomes SAMER NAROUZE, MD, PHD, FIPP Clinical Professor of Anesthesiology and Pain Medicine, OUCOM Clinical Professor of Neurological Surgery, OSU Associate Professor of Surgery, NEOMED Chairman, Center for Pain Medicine Summa Western Reserve Hospital Cuyahoga Falls, Ohio The author reports no relevant financial conflicts of interest.

U

ltrasound (US) provides dire ect

visualization and imaging off various soft tissues without radiatio on

exposure. Therefore, it is a very app pealing option when performing neck injecttions, cal where there is a magnitude of critic soft tissue structures in a compact, very vascular area.

Moreover, US imaging allows real-time needle advancement and monitoring of the spread of injectate, which improve the accuracy of the block and minimize the risk for intravascular injection.

An added benefit of US is that it helps in the diagnosis of associated pathology or aberrant anatomy that may contribute to the patient’s pain presentation (Figure 1).1 The application of US in the interventional management of neck pain has the potential to be safer and more efficacious than traditional approaches in the following procedures: brachial and cervical plexus blocks; lesser, greater, and third occipital nerve blocks; stellate ganglion blocks; scalene muscle intervention for thoracic outlet syndrome; cervical medial branch and facet injections; and cervical nerve root blocks.

There is no intervention in pain management surrounded by more debate than cervical transforaminal

epidural steroid injection. This review will shed light on the safety of the US-guided approach. It also will provide new insight into the technique and the preference for an extraforaminall nerve root approach rather than the traditional transforaminal epidural approach, although the debate continues.

A 2010 American Society of Regional Anesthesia and Pain Medicine evidence-based medicine review of USguided procedures in pain management showed only weak evidence that US is superior to computed tomography (CT) in lumbar facet intra-articular injections (1 small randomized controlled trial [RCT], evidence level Ib). At that time, the recommendations were: “Although we do have few reports suggesting that USguided cervical injections have advantages over fluoroscopy-guided approaches, we don’t have RCT-driven data to support this.”2

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Since that time, there have been quite a few publications on US-guided cervical nerve root injections, cervical medial branch blocks, and cervical facet injections. Most recently, 2 RCTs reported on the advantages of US-guided cervical nerve root block over the traditional fluoroscopy-guided and CT-guided approaches (evidence level Ib for both).3,4

US-Guided Cervical Nerve Root Injections LIMITATIONS

OF THE

FLUOROSCOPY-GUIDED TECHNIQUE

Cervical transforaminal injections (CTFSI) have been performed traditionally with the use of fluoroscopy or CT. There have been a few reports of fatal neurologic complications as a result of vertebral artery injury or infarction of the spinal cord and the brain stem.5-11 The mechanism of injury in these cases is hypothesized to be either vasospasm or unintentional arterial injection of particulate steroid with embolus formation.7,8 Current guidelines for the CTFSI technique involve introducing the needle under fluoroscopic guidance into the posterior aspect of the intervertebral foramen just anterior to the superior articular process in the oblique view to minimize risk for injury to the vertebral artery or nerve root.12 Despite strict adherence to these guidelines, adverse outcomes have been reported. A potential shortcoming of the described fluoroscopyguided procedure is that the needle may puncture a critical contributing vessel to the anterior spinal artery in the posterior aspect of the intervertebral foramen.13

In this case, ultrasonography may provide for new advantages, as it allows for visualization of soft tissues, nerves, and vessels, and the spread of the injectate around the nerve (all potentially advantageous to fluoroscopy). US allows real-time identification of the vessels before needle puncture; this is the most distinctive advantage over fluoroscopic guidance, wherein this complication can be recognized only after aberrant vascular uptake is noted with contrast agent injection. In other words, US can “prevent” intravascular penetration, whereas contrast fluoroscopy can “detect” intravascular injection after the fact.14

Advantages of US-Guided Cervical Nerve Root Block EXTRAFORAMINAL PERIRADICULAR VERSUS TRANSFORAMINAL SPREAD It is very important to identify the target in the USguided technique. The target is the nerve root or more specifically the ventral ramus, in the transverse process groove between the anterior and posterior tubercles. Thus, with US, the procedure is an extraforaminal selective nerve root block. This is in contrast to the fluoroscopy-guided technique, in which the procedure is a transforaminal epidural injection.

As described, with US guidance the needle is intentionally placed extraforaminally to avoid the vascularity within the foramen; accordingly, it is not feasible to monitor the spread of the injectate through the foramen into the epidural space because of the bony artifact of the transverse process. We therefore refer to this approach as a cervical selective nerve root block rather than a CTFSI.15

Figure 2.

Short-axis sonogram (transverse) US image at the level of the Tp of C5 showing an enlarged C5 nerve root, or neuroma. Note that it looks larger than the CA.

Short-axis sonogram (transverse) US image at the level of the transverse process and AP of C6 showing a critical artery crossing the AP on its way to the neuroforamen. Also note the small vessels in the vicinity of the neuroforamen.

CA, carotid artery; IJV, internal jugular vein; Tp, transverse process; US, ultrasound

AP, articular pillar; at, anterior tubercles; pt, posterior tubercles; US, ultrasound

Figure 1.

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Yamauchi et al monitored the efficacy and spread of injectate in US-guided cervical nerve root block in a clinical as well as a cadaveric study.

All target nerve roots in the 12 patients and 10 cadavers were correctly identified by US. This study suggested that there is no difference in the analgesic effects after US-guided injections, although the injectate spread tends to be mainly extraforaminal compared with the conventional transforaminal fluoroscopic technique.16 Lee et al compared the technical differences and clinical outcomes between US-guided cervical periradicular steroid injection (US-CPSI) and conventional fluoroscopy-guided transforaminal epidural injection for the treatment of cervical radicular pain. Their data suggested that US-CPSI can provide an adequate local spread pattern and tissue penetration for the treatment of cervical radicular pain.17

IDENTIFICATION

OF

SMALL CRITICAL VESSELS

Narouze et al reported a pilot study of 10 patients who received cervical nerve root injections using US as the primary imaging tool with fluoroscopy as the control.15 The researchers were able to identify vessels at the anterior aspect of the foramen in 4 patients, and 2 patients had critical vessels at the posterior aspect of the foramen; in 1 patient, this artery continued medially into the foramen most likely forming or joining a segmental feeder artery. In these 2 cases, such vessels could have been injured easily in the path of a correctly placed needle with fluoroscopy (Figure 2).

Jee et al evaluated the efficacy and safety of USguided cervical nerve root block compared with fluoroscopy-guided injection in a prospective RCT. A total of 120 patients were randomly assigned to either fluoroscopy or US. The treatment effects and functional improvement after the nerve root block were compared at 2 and 12 weeks. There were no statistically significant differences between the 2 groups.18

Table 1. Incidence of Vascular Injections With Fluoroscopy-Guided Cervical Transforaminal Injections Study

Injections, N

Vascular Injection, %

With DSA, %

Smuck et al19

121

32.8

–

19.4

–

Furman et al22 504 Nahm et al23

136

20.6

–

Kim et al24

71

63.4

–

17.9

32.8

McLean et al25 134

DSA, digital subtraction angiography

The authors of this study reproduced the findings of Narouze et al, but in a larger cohort of patients. In 21 patients in the US group, vessels were identified at the anterior aspect of the foramen. Eleven patients had a critical vessel at the posterior aspect of the foramen and 5 had an artery continue medially into the foramen.

In the fluoroscopy group, 5 cases of intravascular injections were observed.

Obernauer et al also evaluated the accuracy, time savings, radiation doses, safety, and pain relief after USversus CT-guided cervical nerve root injections in a prospective RCT. The accuracy of US-guided injections was 100%. The mean time to final needle placement in the US group was 2.21±1.43 minutes versus 10.33±2.30 minutes in the CT group. Both groups showed the same significant improvement in visual analog scale pain score.19

Why Ultrasound?

Radiation-free imaging. This is especially important with cervical injections where there is increased scattered radiation from the C-arm.18 Short procedure time compared with CT. Fluoroscopy time was reported to be significantly increased when a vascular injection is identified.4,19 Ability to identify and avoid vessels in the trajectory of the needle. The incidence of vascular injection in fluoroscopy-guided CTSFIs is significantly high (Table 1).19-23 This led to concerns about the safety of the procedure.

However, there were no vascular injections in the reported US-guided cervical nerve root injection studies (Table 2).3,4,15 US is an excellent tool for “visualizing,” and therefore avoiding vascular injury during cervical spine procedures, whereas contrast fluoroscopy can only “detect” that the tip of the needle is intravascularly placed. One should be mindful that fluoroscopy may not detect that the needle already has traversed a vessel in its path to the target, whereas US may help avoid this complication (Figure 2).

Table 2. Incidence of Vascular Injections With US-Guided Cervical Nerve Root Injections

Injections, N

Vascular Injection With US, %

Vascular Injection With Fluoroscopy Control, %

10

0

20

60

0

9

Obernauer 20 et al4

0

NA

Study et al15 Jee et al3

US, ultrasound

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81

US offers dynamic real-time imaging of the cervical spine, therefore averting the need to continuously adjust the C-arm to obtain a true lateral or an oblique foraminal view of the cervical spine.1

US as an adjunct to help identify blood vessels in the vicinity of the foramen.

Caution Needed

• • • • • • •

In previous reports, US-guided cervical nerve root injection was compared with fluoroscopy with realtime contrast injection; however, none of the studies used digital subtraction technology, which might increase the sensitivity of detecting small critical vessels.

I believe that visualization of such small vessels may be challenging, and that it requires special training and expertise.24 No system is perfect, and not seeing a small blood vessel does not necessarily mean it does not exist. It could be either the limitation of US resolution or the limitation of the operator’s experience.

Depending on the experience of the operator, realtime fluoroscopy with contrast injection and digital subtraction—when available—still should be used, with

Pearls for Improving the Safety of Cervical Nerve Root Injection Real-time contrast fluoroscopy Digital subtraction angiography (when available) US guidance Blunt-tip needle Test dose Diagnostic block with local anesthetic only Therapeutic block with nonparticulate steroids

Conclusion US guidance for cervical spine procedures is evolving rapidly. There are now several RCTs reporting the advantages of US in performing cervical nerve root injections compared with fluoroscopy and CT. The future for US-guided cervical procedures is bright because these techniques offer many visual advantages that are not found in fluoroscopy-based techniques.

References 1.

Narouze SN, Provenzano DA. Sonographically guided cervical facet nerve and joint injections: why sonography? J Ultrasound Med. 2013;32(11):1885-1896.

14. Narouze SN. Ultrasound-guided cervical spine injections: ultrasound “prevents” whereas contrast fluoroscopy “detects” intravascular injections. Reg Anesth Pain Med. 2012;37(2):127-130.

2. Narouze SN. Ultrasound-guided interventional procedures in pain management: evidence-based medicine. Reg Anesth Pain Med. 2010;35(2 suppl):S55-S58.

15. Narouze S, Vydyanathan A, Kapural L, et al. Ultrasound-guided cervical selective nerve root block: a fluoroscopy-controlled feasibility study. Reg Anesth Pain Med. 2009;34(4):343-348.

3. Jee H, Lee JH, Kim J, et al. Ultrasound-guided selective nerve root block versus fluoroscopy-guided transforaminal block for the treatment of radicular pain in the lower cervical spine: a randomized, blinded, controlled study. Skeletal Radiol. 2013;42(1):69-78.

16. Yamauchi M, Suzuki D, Niiya T, et al. Ultrasound-guided cervical nerve root block: spread of solution and clinical effect. Pain Med. 2011;12(8):1190-1195.

4. Obernauer J, Galiano K, Gruber H, et al. Ultrasound-guided versus computed tomography-controlled periradicular injections in the middle and lower cervical spine: a prospective randomized clinical trial. Eur Spine J. 2013;22(11):2532-2537.

17. Lee SH, Kim JM, Chan V, et al. Ultrasound-guided cervical periradicular steroid injection for cervical radicular pain: relevance of spread pattern and degree of penetration of contrast medium.

Pain Med. 2013;14(1):5-13.

5. Wallace MA, Fukui MB, Williams RL, et al. Complications of cervical selective nerve root blocks performed with fluoroscopic guidance.

AJR. 2007;188(5):1218-1221.

18. Giordano BD, Baumhauer JF, Morgan TL, et al. Cervical spine imaging using standard C-arm fluoroscopy: patient and surgeon exposure to ionizing radiation. Spine (Phila Pa 1976).

2008;33(18):1970-1976.

6. Rozin L, Rozin R, Koehler SA, et al. Death during transforaminal epidural steroid nerve root block (C7) due to perforation of the left vertebral artery. Am J Forensic Med Pathol. 2003;24(4):351-355.

7. Tiso RL, Cutler T, Catania JA, et al. Adverse central nervous system sequelae after selective transforaminal block: the role of corticosteroids. Spine J. 2004;4(4):468-474.

8. Baker R, Dreyfuss P, Mercer S, Bogduk N. Cervical transforaminal injections of corticosteroids into a radicular artery: a possible mechanism for spinal cord injury. Pain. 2003;103(1-2):211-215.

9. Muro K, O’Shaughnessy B, Ganju A. Infarction of the cervical spinal cord following multilevel transforaminal epidural steroid injection: case report and review of the literature. J Spinal Cord Med. 2007;30(4):385-388.

10. Brouwers PJ, Kottink EJ, Simon MA, Prevo RL. A cervical anterior spinal artery syndrome after diagnostic blockade of the right C6-nerve root. Pain. 2001;91(3):397-399.

11. Beckman WA, Mendez RJ, Paine GF, et al. Cerebellar herniation after cervical transforaminal epidural injection. Reg Anesth Pain Med. 2006;31(3):282-285.

12. Rathmell JP, Aprill C, Bogduk N. Cervical transforaminal injection of steroids. Anesthesiology. 2004;100(6):1595-1600.

13. Huntoon MA. Anatomy of the cervical intervertebral foramina: vulnerable arteries and ischemic neurologic injuries after transforaminal epidural injections. Pain. 2005;117(1-2):104-111.

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19. Smuck M, Tang CT, Fuller BJ. Incidence of simultaneous epidural and vascular injection during cervical transforaminal epidural injections. Spine (Phila Pa 1976). 2009;34(21):E751-E755.

20. Furman MB, Giovanniello MT, O’Brien EM. Incidence of intravascular penetration in transforaminal cervical epidural steroid injections. Spine (Phila Pa 1976). 2003;28(1):21-25.

21. Nahm FS, Lee CJ, Lee SH, et al. Risk of intravascular injection in transforaminal epidural injections. Anaesthesia. 2010;65(9):917-921.

22. Kim do W, Han KR, Kim C, Chae YJ. Intravascular flow patterns in transforaminal epidural injections: a comparative study of the cervical and lumbar vertebral segments. Anesth Analg.

2009;109(1):233-239.

23. McLean JP, Sigler JD, Plastaras CT, et al. The rate of detection of intravascular injection in cervical transforaminal epidural steroid injections with and without digital subtraction angiography. PM & R. 2009;1(7):636-642.

24. Narouze SN, Provenzano D, Peng P, et al. The American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, and the Asian Australasian Federation of Pain Societies Joint Committee recommendations for education and training in ultrasound-guided interventional pain procedures. Reg Anesth Pain Med. 2012;37(6):657-664.

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10TH ANNUAL

•

ANESTHESIOLOGY NEWS SPECIAL EDITION

•

2014-2015