AN Airway Management August 2015

Supplement to Anesthesiology Newss • AnesthesiologyNews.com • 2015-2016

8th Annual Compendium of Clinical Reviews

Introduction by Lorraine J. Foley, MD, MBA

Managing the Difficult Airway: Nine Challenging Cases

A Brief History of Clinical Airway Management

Successful Tracheal Intubation in Children With Difficult Airways: Seven Secret Techniques Every Anesthesiologist Should Know

Airway Management Roundtable: Seven Questions Airway Risk Assessment: A Review of Current Evidence To Aid Clinical Decision-Making Communicating Difficult-To-Intubate Status Throughout A Health Care System

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Supraglottic Airways: Their Evolution as Tracheal Tube Introducers Use of Topical Anesthetics to Support Intubation

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Introduction

Difficult Airway Documentation, Communication and Local to Global Registries LORRAINE J. FOLEY, MD, MBA Clinical Assistant Professor of Anesthesia Tufts School of Medicine Winchester Anesthesia Associates Winchester Hospital Affiliate of Lahey Health Boston, Massachusetts President-Elect, Society for Airway Management

M

ost of us have encountered or will encounter a difficult airway at some point in our career. The worst is when, after having taken care of the patient, you find out that the patient had a history of difficult airway from a previous surgery, and you ask yourself, why did I not know that?

What can I do—what can we do—so that this will not happen to someone else?

Difficult or failed airway is an ongoing threat to patient safety as well as a hazard to not only anesthetic

practice but also anyone else involved with airway management, such as out-of-hospital providers, emergency physicians and intensive care practitioners. Although a large percentage of difficult intubation is anticipated after routine careful airway examination, there are still unanticipated difficult airways. Studies have been done to identify the physical attributes that indicate a difficult airway. A history of a difficult airway has been shown to be an independent risk factor for a second difficult airway event.1,2 Studies have also shown that the more numerous the attempts at intubation, the greater the morbidity.3,4

Guidelines and Recommendations Following the American Society of Anesthesiologists (ASA) Closed Claims Project, the ASA developed an ASA Task Force on Management of the Difficult Airway continued on page 4

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and published practice guidelines for the difficult airway in 1993. They recommended that documentation be made in the medical record of the presence of a difficult airway and the nature of the difficulty, and that the patient should be informed. At about the same time, in 1992, a Medic Alert National Difficult Airway Registry was established by an Anesthesia Advisory Council, with the objective of developing a uniform recording system for the difficult airway and maintaining a central registry of patients.6 In 2003 and more recently in 2013, revised guidelines were published, in which recommendations were made for documentation in the patient’s anesthesia record, verbal communication with the patient together with a written report or letter to the patient, communication with the surgeon and/or primary caregiver, and the use of notification bracelets and chart flags.7,8 In 1998, the Canadian Airway Focus Group recommended noting in the patient’s chart the nature of the problem and how it was dealt with; writing a letter to the patient, surgeon and primary care provider; and entering the information into a dependable database, such as Medic Alert.9 In 2013, a revised guideline was published, which recommended the same steps plus the use of an electronic medical recording and alert system, an in-hospital bracelet, and recording the information in a local or national database.10 The Difficult Airway Society, based in the United Kingdom, also issued guidelines for unanticipated difficult intubation. It also recommended follow-up and placing an alert about the difficult airway with any documentation into the medical record, as well as writing a letter to the patient, surgeon and general practitioner. The patient should also consider use of a Medic Alert bracelet.11,12 Presently, the Society for Airway Management (SAM) is developing guidelines for dissemination of critical information on the difficult airway and has endorsed the National Medic Alert. With the SAM, the Medic Alert Task Force in 2014 updated a designated Difficult Airway Registry (www.medicalert.org/everybody/difficultairwayintubation-registry). This registry enables any health care provider who manages airways to uniformly document the patient’s airway physical exam, the difficult airway’s management and the patient’s outcome, all via the Internet. A registration form can be downloaded, filled out and given to the patient, along with a difficult airway letter explaining the problems encountered and informing the patient of the importance of registering with Medic Alert. Once the patient is registered, this information is accessible globally to provide appropriate airway management.

It is recommended that, just as in the management of a difficult airway, the documentation and dissemination of the condition should have multiple layers, and documentation should be backed up. Documentation should start locally and extend nationally and even internationally. The more people who are informed of the difficult airway, the more likely this important information will be communicated.

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Summarizing the Recommendations From a review of all the relevant recommendations, documentation and dissemination should include: • Documentation in the anesthesia record • Verbal communication to the patient and/or the patient’s caregivers • A letter describing the difficult airway that should go to the patient, surgeon and the patient’s primary care provider; and a copy that should be placed in the patient’s chart together with a notation that the patient has received the letter, which will become part of the patient’s permanent record • An in-hospital bracelet that identifies the patient as having a difficult airway • If possible, inclusion in an in-hospital Difficult Airway Registry • Inclusion in the Medic Alert Difficult Airway Registry What is documented is very important: • Date and institution where the difficult airway was identified • Appropriate provider contact information • Patient characteristics from the airway exam, body mass index and other significant comorbidities • Type of difficulty encountered and explanation; for example, mask ventilation, supraglottic devices, intubation and extubation • A notation of the unsuccessful technique and the type of view seen • A notation of the successful technique that afforded the best view • Implications for the future • Recommendation for registration with Medic Alert Although recommendations for the documentation and dissemination of information about a difficult airway have been around since the early 1990s, surveys and a study have shown that these recommendations have not been widely practiced.13-15 One study surveyed anesthesiologists and general practitioners about writing a letter on the difficult airway. Only 20% of anesthetists consistently wrote a difficult airway letter to the general practitioner. Of those who received such a letter, 98% thought airway information was important but only about half forwarded the information. The general practitioners surveyed recommended labeling the information as “high priority” to ensure that “Difficult Tracheal Intubation” would be listed in the emergency care summary generated for hospital referrals.16 A follow-up survey on the effectiveness of the difficult airway letter to patients found that only 50% of patients remembered having a conversation with an anesthesiologist postoperatively, 80% remembered getting a letter, 41% of primary care providers were aware of the condition and 23% registered with Medic Alert.17

In-hospital difficult airway registries have been found to decrease emergency surgical airways and to help those providers without advanced airway skills to be aware of the challenge and to call for help.18,19 Anesthetic technique may change because a patient has been identified as having a difficult airway.20 In the ASA Perioperative Closed Claims review, greater than 50% of the difficult airway claims were anticipated difficult airways, either because of document history or physical.21 In the NAP4 study, in the United Kingdom, 133 cases had major airway management complications. Of those, difficult airway management was anticipated in about half (66), and there was a history of airway problems in 41 of these 66 cases. In addition, dissemination of information about patients’

difficult airways was found in the notes of 32 of the 66 cases, but only 14 of the patients received some communication about their condition.22 So why, even when anesthesiologists are aware of a difficult airway, do critical airway incidents still occur?

As Cook and MacDougall-Davis found, the answer is often “human factors”—problems in communication, judgment and training.23 Successful implementation of detailed documentation and dissemination of difficult airway information hopefully will help with these issues because this will give consistent, comprehensible information that will be accessible to all health care providers regardless of geographical location and time of day.

References 1.

El-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg. 1996;82:1197-1204.

11. Henderson JJ, Popat MT, Latto IP, et al. Difficult Airway Society guidelines for management of the unanticipated difficult intubation. Anaesthesia. 2004;59:675-694.

2. Lundstrom LH, Moller AM, Rosenstock C, et al. A documented previous difficult tracheal intubation as a prognostic test for a subsequent difficult tracheal intubation in adults. Anaesthesia.

2009;64:1081-1088.

12. Difficult Airway Society. www.das.uk.com/guidelines.

3. Cook T, Woodall N, Frerk C. The 4th national audit project: airway lessons from across the Atlantic. Anesthesiology News Guide to Airway Management. 2012:7-11.

14. Mellado P, Thunedborg LP, Swiatek F, et al. Anaesthesiological airway management in Denmark: Assessment, equipment and documentation. Acta Anaesthesiol Scand. 2004;48:350-354.

4. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg.

2004;99:607-613.

15. Baker P, Moore C, Hopley L, et al. How do anaesthetists in New Zealand disseminate critical airway information? Anaesth Intensive Care. 2013;41:334-341.

5. Practice Guidelines for Management of the Difficult Airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology.

1993;78:597-602.

6. Mark LJ, Beattie C, Ferrell CL, et al. The difficult airway: mechanisms for effective dissemination of critical information. J Clin Anesth. 1992;4:247-251.

7.

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;98:1269-1277.

8. Apfelbaum JL, Hagberg CA, Caplan RA, et al. 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. 2013;118:251-270.

9. Crosby ET, Cooper RM, Douglas MJ, et al. The unanticipated difficult airway with recommendations for management. Can J Anaesth. 1998;45:757-776.

10. Law JA, Broemling N, Cooper RM, et al. The difficult airway with recommendations for management—part 1—difficult tracheal intubation encountered in an unconscious/induced patient. Can J Anaesth. 2013;60:1089-1118.

13. Barron FA, Ball DR, Jefferson P, et al. ‘Airway Alerts’. How UK anaesthetists organize, document and communicate difficult airway management. Anaesthesia. 2003;58:73-77.

16. Wilkes M, Beattie C, Gardner C, et al. Difficult airway communication between anaesthetists and general practitioners. Scott Med J. 2013;58:2-6.

17. Trentman T, Frasco P, Milde L. Utility of letters sent to patients after difficult airway management. J Clin Anesth. 2004;16:257-261.

18. Sheeran PW, Walsh BK, Finley AM, et al. Management of difficult airway patients and the use of a difficult airway registry at a tertiary care pediatric hospital. Paediatr Anaesth. 2014;24:819-824.

19. Berkow LC, Greenberg RS, Kan KH, et al. Need for emergency surgical airway reduced by a comprehensive difficult airway program.

Anesth Analg. 2009;109:1860-1869.

20. Foley L, Sands D, et al. Effect of difficult airway registry on subsequent airway management: Experience in the first two years of the DA registry (abstract). Anesthesiology. 1998;89:A1220.

21. Peterson GN, Domino KB, Caplan RA, et al. Management of the difficult airway: a closed claims analysis. Anesthesiology.

2005;103:33-39.

22. Pearce A, Shaw J. Airway assessment and planning NAP4. In: Major Complications of Airway Management in the United Kingdom.

Cook T, Woodall N, Frerk C, eds. London, UK: The Royal College of Anaesthestists; 2011:135-142.

23. Cook TM, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth. 2012;109:i68-i85.

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Table of Contents 3

Introduction

9

A Brief History of Clinical Airway Management

17

Airway Risk Assessment: A Review of Current Evidence To Aid Clinical Decision-Making

Lorraine J. Foley, MD, MBA

D. John Doyle, MD, PhD, FRCPC

Geoffrey D. Muller, MB ChB, FFICM, FRCA David W. Healy, MD, MRCP, FRCA

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Communicating Difficult-To-Intubate Status Throughout a Health Care System Joseph Loskove, MD

31 39

Airway Management Roundtable: Seven Questions D. John Doyle, MD, PhD • Basem Abdelmalak, MD Richard Cooper, MD, FRCPC • Prof. Giulio Frova, MD William Rosenblatt, MD • Joan E. Spiegel, MD

Supraglottic Airways: Their Evolution as Tracheal Tube Introducers James DuCanto, MD

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Use of Topical Anesthetics to Support Intubation

61

Successful Tracheal Intubation in Children with Difficult Airways: Seven Secret Techniques Every Anesthesiologist Should Know

Carlos Artime, MD • Kenneth Candido, MD Julie Golembiewski, PharmD • Tricia Meyer, PharmD

John E. Fiadjoe, MD • Madhankumar Sathyamoorthy, MBBS, MS Vikram Patel, MD

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Managing the Difficult Airway: Nine Challenging Cases F. Javier Belda, MD, PhD • Jose A. Carbonell, MD, EDAIC Shane V. Cherry, MD • Gabriela Costa, MD • Mariana Cunha, MD Christian Diez, MD, MBA • Norma Dominguez, DO, FAOCA Paula Martínez Fariñas, MD • Carlos Ferrando, MD, PhD, EDAIC Maria João Gomes, MD • Estefania Gracia, MD Eugenio Martínez Hurtado, MD • David J. Kim, MD, MS Michael Kushelev, MD • Patricia Lowery, DO Javier Ripollés Melchor, MD • Miriam Sánchez Merchante, MD Michael B. Meyers, MD • Fernando Moura, MD Carlos R. Degrandi Oliveira, MD, TSA • M. Jose Parra, MD Mackenzie Pullee, DO • Maulik Rajyaguru, DO • Paola Valls, MD Pedro Vasconcelos, MD

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A Brief History of Clinical Airway Management D. JOHN DOYLE, MD, PHD, FRCPC Chief of General Anesthesiology Anesthesiology Institute Cleveland Clinic Abu Dhabi United Arab Emirates Professor of Anesthesiology Cleveland Clinic Lerner College of Medicine Case Western Reserve University Cleveland, Ohio

G

iven the remarkable advances that have occurred in clinical

airway management in recent

years, clinicians may wonder how airway management was performed in earlier times. In fact, the art of clinical airway management is as old as medicine itself.

The author reported no relevant financial disclosures.

Egyptian tablets dating back to 3600 BC appear to depict tracheotomy operations, and reference to the procedure can be found in ancient Hindu scriptures dating from 2000 BC.1,2 Alexander the Great (356-323 BC) is reputed to have saved a soldier from suffocation by making a tracheal incision using the tip of his dagger.3 In AD 100, the Greek surgeon Antyllus described tracheotomy as a “horizontal incision between 2 tracheal rings to bypass upper airway obstruction,”4 and in AD 160, the Roman physician Galen wrote, “If you take a dead animal and blow air through its larynx (through a reed), you will fill its bronchi and watch its lungs attain the greatest dimension.”5 (Figure 1 illustrates a description of the operation in a 17th-century textbook.)

Despite such reports, according to Sittig and Pringnitz, before 1800 only 50 lifesaving tracheotomies had been described in the entire medical literature.6 Common clinical use of the procedure would have to wait until pioneers such as Armand Trousseau and Friedrich Trendelenburg refined and popularized the operation. In 1833, Trousseau reported on his experience with 200 diphtheria patients treated with tracheotomy.7 In 1871, Trendelenburg performed a tracheotomy to prevent blood inhalation during surgery on a patient’s upper airway.8

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Figure 1. Ancient engraving illustrating a tracheostomy procedure.

From Armamentarium chirurgicum bipartitum, 1666. Courtesy of the National Library of Medicine. (Image edited for clarity)

Moving Away From Invasive As experience with tracheotomy grew, clinicians began to consider ways to make the procedure less invasive. In 1880, Scotsman Sir William Macewen described how to relieve airway obstruction by passing an oral tube into the trachea.9 He practiced blind, digital intubation using cadaver models and eventually was able to use this technique clinically. A few years later, New York physician Joseph O’Dwyer developed a system of metal tubing that could be passed blindly to relieve airway obstruction in children suffocating from the pseudomembrane formed in diphtheria infections (Figure 2).10 George Fell subsequently developed an apparatus that could be attached to the O’Dwyer tube system to allow for positive pressure ventilation.11 Fell and others used this combination to provide temporary respiratory support in some patients who were apneic from morphine and other drugs that suppress respiration, as well as to treat patients with pneumothoraces and to allow for thoracic surgical procedures. In Germany, Hans Kuhn modified O’Dwyer’s tube system to create a flexometallic endotracheal tube, with a matching introducer, intended for blind insertion.12 O’Dwyer lived to see his lifesaving airway equipment obviated by Emil von Behring and others who, in 1890, discovered the antitoxins for diphtheria that provided a desperately needed treatment for the deadly infection. In 1901, von Behring was awarded the first Nobel Prize in Medicine.

One significant drawback of O’Dwyer’s intubation system and its variants was that they had to be placed blindly. Direct laryngoscopy solved that problem by allowing clinicians to observe the glottic structures they were attempting to maneuver.

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Figure 2. Joseph O’Dwyer’s glottic tube system.

This was used primarily in the late 1800s to maintain the airway in children with diphtheria. The device was placed blindly and required that the operator place his hand in the child’s mouth to introduce the device. Occasionally, the child would bite the operator, infecting him.

Image courtesy of Case Western Reserve University.

Birth of Laryngoscopy However, it was not a physician but Manuel Garcia (1805–1906), a voice teacher from London, who is generally credited with discovering laryngoscopy. In 1855, Garcia described how he could perform “autolaryngoscopy” using a dental mirror in combination with a second, larger mirror to direct sunlight into his mouth.13 This arrangement allowed him to see his larynx and trachea—a feat fortuitously made possible by Garcia’s absent gag reflex.

The “Autoscope” Others had been working toward a similar solution.

In 1929, an English medical student named Benjamin Guy Babington created a device he dubbed the “glottiscope,” but the invention did not have the impact it deserved.14 Toward the end of the 19th century, Alfred Kirstein of Berlin, Germany, developed the self-named “autoscope” (Figure 3), consisting of a spatula, hood, and handle, which he was inspired to create after learning how an endoscope intended for esophagoscopy had inadvertently slipped into the trachea.15 To assist in viewing the airway, Kirstein also invented what he called a “forehead-lamp for reflected light,” a sort of premodern spelunking headlamp. In 1897, a 68-page translation of Kirstein’s Autoscopy of the Layrnx and the Trachea was published in the United States. The article included

Figure 3. Line engraving of Alfred Kirstein performing laryngoscopy with his laryngoscope.

From: Hirsch NP, Smith GB, Hirsch PO. Alfred Kirstein: pioneer of direct laryngoscopy. Anaesthesia. 1986;41(1):42-45.

Selections From an 1888 Textbook on Intubation of the Larynx

F

ew can appreciate the risks and dangers that were encountered in introducing this operation into private practice. Several times my life was threatened for “putting a plug in a child’s throat.” On one occasion I was obliged to beat a hasty retreat to avoid personal injury, and in another case the coroner was summoned to investigate and to hold me responsible for a child’s death. Through the support and encouragement of my brother practitioners, however, I was enabled to persevere until the operation became established as a legitimate procedure.

Intubation has now become so thoroughly recognized as a practical and successful operation, that I believe it to be a duty the medical profession at large owe to the public, that at least one physician in every village, town, and city throughout this great country, should possess the necessary instruments, pluck, and skill to successfully perform this operation.

A Case Report May 5th, 1886. Courtesy Drs. Steele and Lawless. Termination, recovery. Age, fourteen months. Wore the tube three and a half days. Diphtheritic patches upon the tonsils, and the child almost dead from laryngeal obstruction. Intubation gave immediate relief.

The baby did well for two days, when the tube was removed. As respiration was carried on with difficulty, the tube was again introduced. The child did poorly

for the next twenty-four hours, the respiration being rapid and somewhat embarrassed and moist sibilant rales were heard in both lungs. Little hope of recovery was entertained. The tube was removed, but the child was still unable to carry on respiration without it, and it was again introduced. Twelve hours later the patient was found in convulsions, and while not severe, were of frequent occurrence. The case now seemed entirely hopeless, but it was thought best to remove the tube, which was done while the child was in the stupor following a convulsion. The respiration, although rapid, numbering seventy per minute, was easily performed, and the tube was dispensed with. The bromides were given per rectum to control the convulsions, and carbonate of ammonia given in the milk as soon as the child was able to swallow. As the moist sibilant rales continued flax seed poultices well covered with oilsilk, were applied to the chest. Gradually the little one improved, and in a few days was on the safe road to recovery, and is at this writing as fine and healthy a child as is to be found in the city of Chicago.

By F.E. Waxham, MD Professor of Otology, Rhinology and Laryngoscopy College of Physicians and Surgeons of Chicago Clinical Professor of Laryngology and Rhinology Chicago Ophthalmic College Published by Charles Truax Chicago, IL; 1888

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a description of the device, case studies, and a dozen illustrations of the procedure.16 Along with a nod to the virtues of cocaine as an anesthetic in laryngologic surgery, Kirstein’s preface consisted of an argument for acceptance of his technique, couched in compromise:

time, never viewed the interior of the larynx directly (without a mirror) is certainly not due to logical reasoning, but because we had no idea of such a possibility. ... In the second place, this method is not intended to replace the laryngoscopic method, but to add to it.”16

“It may appear a rash undertaking for me to deviate from time-honored tradition, and to open up an entirely new way for the examination and treatment of the larynx and the trachea, by teaching that we can view the interior of the air-passages directly, without the aid of optical appliances, and operate with straight (uncurved) instruments in the same manner. Nevertheless, my undertaking is doubly justified. In the first place, because of the facts themselves, which may be demonstrated at any time, and which I have made known in a series of publications. ... The fact that we have, up to this

Kirstein goes on to describe the airway anatomy and his device: “The spatula for adults is 14 centimetres long; at the tip it is about 2 centimetres wide, and it is about 1½ centimetres wide where it passes the convexity of the tongue.”

The monograph also contains helpful warnings to novices using autoscopy: “The lower half of the trachea is a region off great danger! ... During the examination of a number of healthy people the aortic arch has often seemed to protrude like a hump, as it were, into the trachea; so that the beginner in autoscopy would be tempted to diagnosticate an aneurism where none exists.”

Table. Landmarks in Clinical Airway Management Biblical times

Death from airway obstruction recognized (trauma [strangulation], leprosy, abscesses)

1700s

Metal and leather tubes inserted blindly into the trachea for treatment of drowning

1842

Long discovers ether anesthesia

1854

Garcia develops indirect laryngoscopy

1878

Chloroform administered through tracheal tube (Macewen)

1885

O’Dwyer popularizes intubation for diphtheria

1895

Kirstein develops direct laryngoscopy

1900

Kuhn develops a flexometallic tracheal tube

World War I

Many casualties requiring head and neck surgery add impetus to widespread use of intubation in military hospitals; Magill introduces tracheal tube with inflatable cuff

1920

Jackson designs improved laryngoscope

1920s

Magill develops blind nasal intubation

1942

Griffiths introduces curare into clinical practice

1946

Mendelson describes aspiration pneumonitis

1950s

Popularization of use of tracheal tubes for general anesthesia

1960s

Advent of electronic patient monitoring

1962

Sellick maneuver and rapid-sequence induction developed

1940s-1970s

Continuing improvements in laryngoscope and tube designs; use of plastic

1970s

Development of implant-tested low-irritation, low-cuff pressure disposable tracheal tubes

1980s

Popularization of fiber-optic intubation. Introduction of pulse oximetry and capnography as noninvasive means of assessing oxygenation and ventilation

1990s

Popularization of laryngeal mask airway, rigid fiber-optic laryngoscopes (Bullard, Wu, etc) and ASA Practice Guidelines for Management of the Difficult Airway. Increased awareness of the special challenges of the “difficult extubation” patient

1995

Founding of the Society for Airway Management (www.samhq.com)

2000s

Introduction of video laryngoscopes (GlideScope, McGrath, etc)

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Kirstein’s autoscope was subsequently modified by Chevalier Jackson to provide distal illumination with a tungsten light bulb.

Modern Devices Arrive The 1940s saw the development of 2 laryngoscopes that are still in widespread clinical use. In 1941, Robert Miller described his straight laryngoscope blade, and in 1943, Sir Robert Macintosh described his curved blade, which he hoped that by minimizing contact with the epiglottis, his laryngoscope would be less stimulating.17,18 Meanwhile in 1942, Harold Griffiths of Montreal, Canada, introduced curare as a muscle relaxant with the goal of facilitating abdominal surgery and other procedures.19 Tracheal intubation soon became routine in major surgical operations.

Although 60 years later variations of the Macintosh and Miller laryngoscopes remain widely used, both devices occasionally fail to provide adequate glottic views, prompting continued efforts to improve their designs. The result has been a series of innovations, including fiber-optic bronchoscopes optimized for intubation, the Bullard laryngoscope and its variants, the McCoy articulating laryngoscope, various optical stylettes, and video laryngoscopes such as the GlideScope (Verathon) and the McGrath video laryngoscope (LMA North America).

O

n a frigid Virginia afternoon in December 1799, three physicians gathered around a dying man who writhed in distress as he gasped unsuccessfully for air. The physicians gave the man sage tea with vinegar to gargle, but it nearly caused him to choke to death. Poultices did little to help.

It had been only a year since the medical literature of the time described a surgical procedure in which the trachea could be accessed in cases of airway obstruction. In 1799, even elective tracheotomy, let alone emergent tracheotomy, was rarely performed.

The man’s condition continued to deteriorate as he struggled for breath. One of the physicians had heard of the tracheotomy procedure but was reluctant to

Figure 4. Early prototypes of the Laryngeal Mask Airway.

Image courtesy of Archie Brain, MD.

Any history of airway management would be incomplete without mentioning supraglottic airway devices such as the Laryngeal Mask Airway (LMA; LMA North America). Archie Brain, the inventor of the LMA, went thorough a considerable variety of prototype designs before the clinical launch of the LMA in the 1980s (Figure 4). Many people are unaware, however, that

attempt it on such a famous person because the procedure was considered futile and irresponsible. Soon the patient became calm and expired—becoming the first American president to die.

Although arguments persist about the exact cause of George Washington’s death, one popular theory is that he died from an upper airway obstruction caused by bacterial epiglottitis.

From Steven E. Sittig and James E. Pringnitz. Tracheostomy: evolution of an airway. AARC Times. February 2001. (See also Figure and Morens DM. Death of a president. N Engl J Med. 1999;341[24]:1845-1849.)

Figure. The deathbed of George Washington.

In December 1799, George Washington developed a sore throat accompanied by fever, swelling, and difficulty swallowing. He was diagnosed with an “inflammatory quinsy.” Although one of his physicians, Elisha Cullen Dick, proposed performing a tracheotomy to aid Washington’s breathing, this suggestion was rejected by the other physicians.

Instead, Washington was repeatedly phlebotomized (to a total of 5 pints of blood). Undoubtedly, this therapy contributed to his death.

Image courtesy of the Dayton Art Institute.

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References 1.

Pahor AL. Ear, nose and throat in ancient Egypt. J Laryngol Otol.

1992;106(9):773-779.

2. Stock CR. What is past is prologue: a short history of the development of the tracheostomy. Ear Nose Throat J. 1987;66(4):166-169.

3. Szmuk P, Ezri T, Evron S, Roth Y, Katz J. A brief history of tracheostomy and tracheal intubation, from the Bronze Age to the Space Age. Intensive Care Med. 2008;34(2):222-228.

4. Ferlito A, Rinaldo A, Shaha AR, Bradley PJ. Percutaneous tracheotomy. Acta Otolaryngol. 2003;123(9):1008-1012.

5. Stoller JK. The history of intubation, tracheotomy and airway appliances. Respir Care. 1999;44(6):595-603.

6. Sittig E, Pringnitz JE. Tracheostomy: evolution of an airway. AARC Times. February 2001.

7. Ezri T, Evron S, Hadad H, Roth Y. Tracheostomy and endotracheal intubation: a short history. Harefuah. 2005;144(12):891-893, 908.

8. Keys TE. The history of surgical anesthesia. New York, NY: Dover Publications; 1963.

9. Macewen W. Introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy. Br Med J. 1880;II:122–124.

10. Westhorpe R. O’Dwyer’s tubes. Anaesth Intensive Care.

1991;19(2):157.

11. Fell SC. A history of pneumonectomy. Chest Surg Clin N Am. 1999;9:267-290.

12. Thierbach A. Franz Kuhn, his contribution to anaesthesia and emergency medicine. Resuscitation. 2001;48(3):193-197.

Figure 5. Leech’s pharyngeal bulb gasway, 1937.

A description of Beverley C. Leech, MD, and his invention is available at www.cja-jca.org/cgi/reprint/37/6/689.pdf.

13. Alberti PW. The history of laryngology: a centennial celebration.

Otolaryngol Head Neck Surg. 1996;114(3):345-354.

14. Harrison D. Benjamin Guy Babington and his mirror. J Laryngol Otol. 1998;112(3):235-242.

15. Hirsch NP, Smith GB, Hirsch PO. Alfred Kirstein: pioneer of direct laryngoscopy. Anaesthesia. 1986;41(1):42-45.

16. Kirstein A [Thorner M, translator]. Autoscopy of the Larynx and the Trachea. Philadelphia, PA: The F.A. Davis Co.; 1897.

other supraglottic airways (Figure 5) were in clinical use long before the invention of LMA, although these devices were eventually eclipsed by the popularization of tracheal intubation following the popularization of curare.

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17. Miller RA. A new laryngoscope. Anesthesiology. 1941;2:317–320.

18. Macintosh RR. A new laryngoscope. Lancet. 1943;1:205.

19. Griffiths HR, Johnson GE. The use of curare in general anaesthesia.

Anesthesiology. 1942;3:418-420.

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Airway Risk Assessment: A Review of Current Evidence To Aid Clinical Decision-Making

GEOFFREY D. MULLER, MB CHB, FFICM, FRCA DAVID W. HEALY, MD, MRCP, FRCA Department of Anesthesiology University of Michigan Medical School Ann Arbor, Michigan The authors report no relevant financial disclosures.

C

ompetent airway management is

essential in the performance of safe anesthesia. All anesthetics

should be preceded by a focused history of previous airway management and physical examination of the airway.1 The objective of airway assessment is not to determine the presence or absence of various clinical signs; instead, the information gained should be used to identify and stratify the risks involved in managing the patient’s airway.

A risk assessment can guide the airway management plan, allowing specialized skills and equipment to be deployed at the bedside. We will show how the airway evaluation can be used to classify patients into three major risk categories, thereby guiding the overall approach to airway planning and management. For the purposes of this article, we will limit the scope of discussion to patients undergoing elective surgery without airway pathology.

Risk assessment is already practiced in many fields, including financial investment, environmental science, and occupational health and safety. Varying definitions of risk assessment exist for each specific field but generally risk assessment involves identifying hazards, quantifying the likelihood of occurrence, evaluating the degree of harm that the threat poses, and preventative actions that can be employed to mitigate the risk. In order to conduct an airway risk assessment, one needs to identify those risk factors that may cause standard airway techniques to be difficult or fail, and to evaluate the likelihood of that difficulty.

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The difficult airway is often loosely defined and sometimes poorly understood. Complicating the difficulty can be anatomic, procedural, or contextual factors.

For example, difficulty may be experienced during the care of a patient with a physically normal airway but the procedural competence is compromised by a heightened sense of urgency (eg, during endotracheal intubation for an emergency cesarean delivery), leading to a deterioration in human procedural performance. This decline in human performance may be predisposed by poor equipment provision and compounded by limited training or expertise. Procedural difficulty and failure can occur during any of the techniques used to provide airway support.

We will present the existing evidence for increased risk for failure for each aspect of airway management.

We will highlight the particular clinical relevance of the predictors of combined difficult bag mask ventilation (BMV) with difficult endotracheal intubation. We will then present a solution to guide decision-making, procedural choice, skill acquisition, and equipment provision at the point of care.

Difficult Bag Mask Ventilation Much of the existing work to delineate risk factors for encountering difficulty during airway management has focused on the predication of difficult direct laryngoscopy (DL) or endotracheal intubation rather than the ability to perform BMV. Despite its importance in overall airway management and its specific role as the first rescue maneuver after failed endotracheal intubation,1 the ability to perform adequate BMV has only been a focus of investigation relatively recently.

The first major investigation was published in 2000

by Langeron et al, which found a 5% incidence of difficult BMV in a prospective study of 1,502 patients. The outcome was rather loosely defined as “clinically relevant difficulty with BMV which could have led to potential problems if BMV had been maintained for a longer time.�2 This study found that the presence of a beard, body mass index (BMI) greater than 26 kg/m2, a lack of teeth and a history of snoring predicted difficult BMV, according to the definition used (Table).2 The outcome was further studied by Kheterpal et al,3 where difficult BMV was defined as that which

Table. Predictors of Difficulty or Failure With Various Airway Management Techniques Bag Mask Ventilation

Supraglottic Airway

Bag Mask Ventilation + Direct Video Laryngoscopy Laryngoscopy

Direct Laryngoscopy

Beard Edentulous BMI >26

Beard Poor dentition Obesity

Mallampati III/IV

Buck teeth

a

Presence of teeth

a

Obesity

BMI >30

Mallampati III/IV

Mallampati III/IV

Snoring/Sleep apnea

Sleep apnea

Age >57 y

Age >46 y a

Limited jaw protrusion

Limited jaw protrusion

Neck radiation Male

Limited jaw protrusion Abnormal neck anatomy

Male

Neck mass, radiation, increased thickness Male

Rotation of OR table Sternomental distance Thyromental distance

Thyromental distance Thyromental distance

Mouth opening Limited cervical motiona Limited cervical motion Institution a

From Wilson score

BMI, body mass index

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Limited cervical motion

is inadequate to maintain oxygenation, unstable, or requires two or more providers. This group reconfirmed the risk factors for difficulty as including the presence of snoring, obesity (BMI >30 kg/m2), and a beard, but also added the modified Mallampati scores III or IV, age older than 57 years, and severely limited jaw protrusion to the list of independent predictors.

Risk factors for impossible BMV received additional scrutiny, the outcome defined as “the absence of endtidal carbon dioxide measurement and absent chest wall movement during positive-pressure ventilation attempts despite the use of airway adjuvants and two person ventilation attempts.� The specific predictors of impossible BMV were found to be a reported history of snoring and a thyromental distance of less than 6 cm.3 In an additional review of over 50,000 cases, the incidence of difficult and impossible BMV (defined as in the previous study) was found to be 2.2% and 0.15%, respectively.4 Independent risk factors for impossible BMV were Mallampati classification III or IV, male sex, presence of a beard, and a history of sleep apnea. However, interestingly, the strongest predictor was the presence of neck radiation changes (adjusted hazard ratio, 7.1), with the authors advising special consideration of the performance of awake intubation in patients with neck radiation changes who have additional risk factors for impossible BMV.

Difficult Supraglottic Airway Placement The failure rate of different supraglottic airways (SGA) has been variably expressed as 0.2%5 to 4.7%,6 the variance relating to the variety of definitions of failure and type of SGA. Ramachandran et al, in their retrospective review of 15,795 laryngeal mask airway (LMA) insertions performed in a large academic medical center, discovered that 1.1% of patients with an LMA Unique experienced an airway event requiring endotracheal intubation.7 In their study population, they found the independent risk factors for LMA failure to be rotation of the surgical table, male sex, poor dentition, and higher BMI. The American Society of Anesthesiologists’ (ASA) difficult airway guidelines of 20131 continue to place early SGA use in the algorithm for failed DL with difficult BMV airway rescue, and it is reassuring to note the high success rate of SGA use as a rescue in this event. A description of a case series reported that placement of an SGA restored ventilation in 16 of 17 cases of difficult BMV combined with difficult intubation.8

They found an extremely wide range of reported intubation difficulty or failure, which varied with the definition used: grade 3 or 4 Cormack-Lehane view = 10.1%; 3 attempts at DL = 1.9%; 4 attempts = 0.5%; and failure to insert an endotracheal tube using DL = 0.1%.9 Difficult intubation has been variably defined according to access (ability to place a device through the mouth), visualization (of the glottis), and eventual endotracheal tube passage. Difficult laryngoscopy is more correctly applied to failure to perform adequate laryngoscopy because of either failed access or poor glottic visualization.

In a meta-analysis of 35 trials reviewing 50,760 apparently normal patients (excluding those with anatomic abnormalities or presumed difficult airways), Shiga et al showed the overall incidence of difficult intubation (defined by them as the presence of a CormackLehane grade 3 or 4 during DL) to be 5.8%.10 The review emphasized the poor predictive value of the existing individual airway measures. Other predictors reviewed included the Wilson risk score, subjective assessments of sternomental distance, mouth opening, Mallampati classification, and thyromental distance.

The ability to predict difficulty improved when airway measures were used in combination; their findings showed that the use of the Mallampati score combined with thyromental distance is an improved predictor (odds ratio [OR], 3.3; area under the curve [AUC], 0.84).

Rose and Cohen analyzed risk factors in 18,205 patients undergoing DL and intubation (alternative

Difficult Laryngoscopy and Difficult Intubation Difficult intubation is an often poorly defined outcome, leading to a variety of definitions in clinical use.

This variability has hampered investigations into its prediction. A study by Rose and Cohen of 3,325 consecutive adult patients scheduled to undergo DL and intubation (excluding patients anticipated to be difficult undergoing alternative techniques) illustrates this well.

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approaches to DL were excluded).6 They defined difficult intubation as three or more attempts at laryngoscopy and found the risk factors for this outcome to be male sex, middle age (40-59 years), and obesity. Preoperatively evaluated airway measures associated with an increased risk for difficult intubation included reduced mouth opening (relative risk [RR], 10.3), reduced thyromental distance (RR, 9.7), Mallampati score III or IV (RR, 4.5), and limited neck extension (RR, 3.2).

The utility of combining the Mallampati evaluation with a measure of reduced thyromental distance has been confirmed by other investigators. In a small study of 244 patients, Frerk11 showed a combined positive predictive value (PPV) of 64.3% versus thyromental distance of 7 cm or less alone (PPV, 18.5%) or Mallampati score III or higher alone (PPV, 17.3%) for predicting grade 3 or higher laryngoscopy or the use of an airway bougie. Iohom et al12 used the same definition of difficult intubation, again in a small prospective study (N=212), and found a PPV of 100% when Mallampati score III or higher was combined with either sternomental distance less than 12.5 cm or thyromental distance less than 6.5 cm, whereas individually the PPV was Mallampati, 27%; thyromental distance, 47%; and sternomental distance, 62%.

In the largest study of the performance of the upper lip bite test (ULBT) to predict a limited glottic view on DL (Cormack-Lehane grade ≼3), Myneni et al13 enrolled nearly 7,000 North American subjects. The inability to bite the upper lip was found to have a very low PPV (17.4%) and sensitivity (9.8%). The authors could not recommend this as a useful single measure in the North American population.

A smaller study (N=380) in a Middle Eastern population by Khan et al has shown greater utility of the ULBT.14 Using the same diagnostic criteria, Khan et al showed superior performance of the ULBT to standard airway measures with regard to specificity and accuracy (sensitivity, 78.9%; specificity, 91.9%; PPV, 33.3%; and accuracy, 91.0%). A combination of ULBT and sternomental distance less than 13.5 cm was found to be most sensitive.

Difficult Video Laryngoscopy The use of video laryngoscopy has increased considerably over the past decade. Aziz et al performed a review of 2,004 GlideScope (Verathon) intubations, performed in two North American academic medical centers, which revealed the GlideScope to be highly successful in patients both with and without established predictors of difficult DL. In this review, 96% of patients with one or more preoperative predictors of difficult laryngoscopy were successfully intubated when the GlideScope was used as the primary laryngoscopic device.15 A striking finding from this study was the preserved high endotracheal intubation success rate (94%) when the GlideScope was used as a rescue device after failed initial DL.15

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The data were further analyzed to identify independent predictors of GlideScope intubation failure. These predictors were found to be the presence of abnormal neck anatomy (scar, radiation or mass: OR, 4.39), thick neck (OR, 3.21), thyromental distance less than 6 cm (OR, 2.53), limited cervical motion (OR, 1.76), and institution (OR, 2.28). The differing rates of failure between the two institutions in this study were considered to be related to experience with the GlideScope. The center with better success rates had a greater duration and frequency of GlideScope use, suggesting improved chances of successful intubation with practice and familiarity.

Combined Failure of Airway Management Techniques The clinical reality of airway management is that when one procedural aspect fails or is difficult (eg, initial BMV), patient harm is commonly avoided by the timely use and success of other procedural interventions (eg, DL or LMA insertion, etc). When two or more of the common airway management modalities (BMV, DL, video laryngoscopy, SGA) fail, this compounds the overall difficulty, limits the rescue methods available, and may lead to failed oxygenation and patient harm.16 Deterioration in oxygenation during airway management is more likely during the care of patients with high intrinsic oxygen requirements (such as in pediatric or obese patients) or related to a pathologic process (such as acute respiratory distress syndrome or sepsis).

Studies investigating these complex airway situations are limited but of particular interest and relevance to patient safety.

The relative clinical scarcity of the combined incidence of difficult BMV with difficult DL (3 or 4 Cormack-Lehane view) was revealed by a review performed by the Multicenter Perioperative Outcomes Group of over 170,000 procedures over four tertiary referral academic medical centers,17 with a 0.40% incidence (698 cases) of difficult or impossible BMV in combination with grade 3 or 4 DL. Independent predictors of this combined outcome included age 46 years or older, BMI of 30 kg/m2 or greater, male sex, Mallampati III or IV, presence of a neck mass or radiation changes, limited thyromental distance, sleep apnea, presence of teeth, beard, thick neck, limited cervical spine mobility, and limited jaw protrusion. The authors developed the risk index classification system (or RICS) based on the number of these independent predictors.

Powers of Prediction The low failure rates of airway management in large North American academic medical centers are revealed by recent large database studies.3,4,17 Given this low incidence, poor prediction is a mathematical certainty exacerbated by the modest sensitivity and specificity of existing airway measures. Our limited current diagnostic ability to predict difficult airway management

is catalogued in a recent cohort of 188,064 Danish patients.18 In routine cases (without history of difficulty or airway pathology requiring an awake technique), 93% of difficult intubations and 94% of episodes of difficult BMV remained unanticipated. Conversely, when airway difficulty was anticipated (but in cases where securing the airway using advanced methods, eg, awake fiberoptic intubation, was not deemed necessary) by the anesthesia provider, difficulty was subsequently only encountered in 25% of intubations and 22% of BMV attempts. When all cases were considered, including those predicted to need advanced airway methods, the ability to predict difficulty rose to 60% of difficult intubations in a population with a background incidence of 2.28%.

The airway evaluation performed well as a strong diagnostic test with high positive likelihood ratios (LR+)— difficult intubation, 65.19; difficult BMV, 43.68— when compared with other commonly used tests: eg, Mini Mental State Exam for dementia, LR+ 2.5; ultrasound for proximal deep-vein thrombosis in symptomatic patients, LR+ 47.5; and ST elevation for myocardial infarction, LR+ 11.2. In other words, the standard airway risk assessment seems to perform well at “ruling in” difficulty in those with severe or obvious abnormality but is less effective in detecting difficulty in “normalappearing” patients. Unfortunately, this latter group is numerically larger, leading to the greatest difficulty being unanticipated in normal-appearing patients.

Given the poor predictive power of our existing preoperative airway risk assessment, even when difficulty is indicated, clinical inertia may conspire to continue with routine airway management rather than to secure the airway by advanced options (video laryngoscopy or awake techniques). The current clinical reality is that almost half of all patients with a predicted risk for difficult intubation in a Danish study were scheduled for standard induction and DL, and difficulty was actually encountered on 1.86% of these occasions.18 Additionally, the ASA Closed Claims database revealed the primary airway management strategy in 61% of cases with anticipated difficult airway to be intubation after induction of general anesthesia.16 Planning for safe airway management needs to overcome this tendency to carry on regardless.

In an attempt to synthesize multiple aspects of the airway evaluation, El-Ganzouri et al developed a risk assessment tool from the examination of a population of over 10,000 cases.19 A weighted score of 7 variables had a greater PPV and higher sensitivity than the highest-performing individual airway measure—the Mallampati score of III (OR, 8.91). Using this simplified airway risk index (SARI), fewer false positives (ie, special intervention for patients who turn out not to have a difficult laryngoscopy) and fewer false negatives (ie, unanticipated difficult laryngoscopy) were encountered compared with use of the Mallampati score. Unfortunately, this trial was underpowered to identify predictors of

difficult BMV, so its clinical utility is centered on anticipating difficult laryngoscopy and predicting the need for alternative equipment to DL. The DIFFICAIR trial20 will prospectively compare standard clinical airway assessment with the SARI to predict difficult DL, and will also compare the ability of systematic documentation of the risk factors for difficult BMV (identified by Kheterpal et al3,4 ) to predict difficult BMV.21 This study should provide insight into whether these predictors generated from large patient series perform better than the standard clinical airway assessment in predicting airway difficulty.

Optimal Clinical Decision Making Using Airway Risk Assessment The airway risk assessment should lead a provider to a considered opinion regarding the increased incidence of encountering difficulty during airway management before procedural difficulty is encountered. In this way, the provider is afforded the chance to change the initial method of airway management or improve the level of skills and equipment at the bedside. Our recommended approach is to perform a pre-procedural airway risk assessment followed by stratification into three risk categories: likely easy, maybe difficult, and likely difficult (known difficult) (Figure).

The “likely easy” group corresponds to patients with few to no risk factors for difficulty where proceeding with general anesthesia and securing the airway with DL is appropriate. Typically, these patients have an SARI of 3 or lower or a RICS score of 5 or lower. We earlier discussed that unexpected airway difficulty is unlikely but still encountered in this group, thereby making the presence of standard airway rescue equipment essential.

Patients with more identified risk factors are considered at an incrementally higher risk for difficulty; however, we have discussed how the true incidence remains in a “clinical gray zone.” Our preparations for airway management must be guided by an educated clinical decision performed on a case-by-case basis, based on the presence or absence of risk factors.

For patients considered “at higher risk for difficulty,” this clinical decision must initiate the consideration of a series of airway management plans, each with skills and equipment to support their performance at the patient’s bedside (for instance, the presence of a video laryngoscope and the skills to use it). Many of these patients will ultimately be easily managed with conventional BMV and DL, but the presence of back-up plans serves as a safety net for the minority.

Ensuring correct equipment provision, optimal head positioning (with the use of the ramped position, if required), and thorough preoxygenation before induction of anesthesia should occur before any airway management procedure. However, this has particular importance after the identification of increased risk to ensure the best chance of success on the initial attempt and continued patient safety during additional attempts. A video laryngoscope could be used

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during the initial laryngoscopic attempt or in the event of failed DL. A correctly sized SGA should be available for use in the event of failed BMV, or to facilitate a conduit approach to endotracheal intubation.

As discussed, the presence of overlapping risk factors predicting difficulty and failure of both difficult DL and BMV4 affords this group particular risk. When considering the existing scoring systems, those subjects in the “at higher risk” group have a SARI of 4 or higher or a RICS score of 6 or higher.

Subjects with a known difficult airway (eg, identified from information in the electronic health record or Medic Alert bracelet) or who have multiple significant risk factors for failure of BMV, intubation, or video laryngoscopy, or simultaneous failure in several of these management modalities (eg, difficult or impossible BMV with DL) should be considered to be in the “known difficult” group.

In an elective context, a technique that retains spontaneous ventilation should be used. Our preferred strategy would be an awake fiber-optic intubation in those requiring a general anesthetic (awake video laryngoscopy is another alternative). Severely limited mouth opening, combined with limited neck extension (precluding DL, SGA, and video laryngoscopy), should be considered at very high risk for difficulty due to the potential failure of multiple airway management modalities. Additional consideration should be given to the performance of an awake technique in patients who would otherwise be thought to be at “higher risk/maybe difficult” but who have impalpable anatomic landmarks or contraindications for surgical airway access.

The overall clinical context of the patient and medical team may also influence the airway management category. For instance, an awake technique may be considered in a patient only thought to be at higher risk for difficulty but with severe gastroesophageal reflux disease to avoid aspiration during multiple attempts at intubation. Similarly, an awake technique may be considered in a patient with borderline pulmonary physiology

preoperatively who may not tolerate the suboptimal ventilation generated by an improperly fitting face mask or SGA. The practitioner’s skill level with different airway apparatuses and the availability of these items also affect which strategy is used.

Conclusion Unfortunately, our current airway evaluation has limited discriminatory ability due to its poor predictive power and the scarcity of the outcome of true difficulty during airway management. Given this inherent unpredictability, difficulty (unanticipated or otherwise) will continue to occur during the various aspects of airway procedural performance. However, recent investigations have provided us with a selection of risk factors that independently predict airway procedural difficulty and failure. The challenge is in how this diverse information can be used to determine our pre-procedural decision-making.

This review has presented the risk factors associated with procedural failure of the individual components of overall airway management, with particular emphasis on the clinical importance of combined procedural failure.

Then we presented a description of how the identification of known risk factors can be used to support clinical decision-making by risk assessment and categorization of patients into those whose airway management is considered to be likely easy, at higher risk for difficulty, and known difficult (likely difficult). This type of decisionmaking allows us to modify airway management plans and ensure that additional equipment (and skills to use them) are present at the point of care when required.

Additional work is needed to improve the predictive power of those airway measures (used individually or in combination) informing our airway risk assessment. In the meantime, we must improve our clinical application of risk assessment with the help of cognitive aids such as checklists, flowcharts, and real-time airway risk assessment calculators embedded within the electronic health record. Additional technological innovation will

Likely easy

At higher risk

Known difficult

L

L

L

Standard equipment DL with usual backups

Series of airway plans Rescue VL available LMA ready

Awake technique Spontaneous ventilation maintained

Figure. A pre-procedural airway risk assessment stratifies patients into categories of risk, which can be used to plan airway management.

DL, direct laryngoscopy; LMA, laryngeal mask airway; VL, video laryngoscopy

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improve our procedural success during predicted and unexpected difficult airway management. Until such improvement is realized, we must ensure that our

airway evaluation, decision-making, technical skills, and equipment provision are optimized to ensure patient safety.

References 1.

Apfelbaum JL, Hagberg CA, Caplan RA, et al. 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. 2013;118(2):251-270.

2. Langeron O, Masso E, Huraux C, et al.. Prediction of difficult mask ventilation. Anesthesiology. 2000;92(5):1229-1236.

3. Kheterpal S, Han R, Tremper KK, et al. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology.

2006;105(5):885-891.

4. Kheterpal S, Martin L, Shanks AM, et al.. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics.

Anesthesiology. 2009;110(4):891-897.

5. Verghese C, Brimacombe JR. Survey of laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage. Anesth Analg. 1996;82(1):129-133.

6. Rose DK, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth. 1994;41(5 Pt 1):372-383.

7.

Ramachandran SK, Mathis MR, Tremper KK, et al. Predictors and clinical outcomes from failed Laryngeal Mask Airway Unique™: a study of 15,795 patients. Anesthesiology. 2012;116(6):1217-1226.

8. Parmet JL, Colonna-Romano P, Horrow JC, et al. The laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation. Anesth Analg. 1988;87(3):661-665.

9. Rose DK, Cohen MM. The incidence of airway problems depends on the definition used. Can J Anaesth. 1996;43(1):30-34.

10. Shiga T, Wajima Z, Inoue T, et al. Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology. 2005;103(2):429-437.

11. Frerk CM. Predicting difficult intubation. Anaesthesia.

1991;46(12):1005-1008.

12. Iohom G, Ronayne M, Cunningham AJ. Prediction of difficult tracheal intubation. Eur J Anaesthesiol. 2003;20(1):31-36.

13. Myneni N, O’Leary AM, Sandison M, et al. Evaluation of the upper lip bite test in predicting difficult laryngoscopy. J Clin Anesth.

2010;22(3):174-178.

14. Khan ZH, Mohammadi M, Rasouli MR, et al. The diagnostic value of the upper lip bite test combined with sternomental distance, thyromental distance, and interincisor distance for prediction of easy laryngoscopy and intubation: a prospective study. Anesth Analg.

2009;109(3):822-824.

15. Aziz MF, Healy D, Kheterpal S, et al. Routine clinical practice effectiveness of the Glidescope in difficult airway management: an analysis of 2,004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology. 2011;114(1):34-41.

16. Peterson GN, Domino KB, Caplan RA, et al. Management of the difficult airway: a closed claims analysis. Anesthesiology.

2005;103(1):33-39.

17. Kheterpal S, Healy D, Aziz MF, et al. Incidence, predictors, and outcome of difficult mask ventilation combined with difficult laryngoscopy: a report from the multicenter perioperative outcomes group. Anesthesiology. 2013;119(6):1360-1369.

18. Nørskov AK, Rosenstock CV, Wetterslev J, et al. Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database. Anaesthesia. 2015;70(3):272-281.

19. el-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg. 1996;82(6):1197-1204.

20. Nørskov AK, Rosenstock CV, Wetterslev J, et al. Incidence of unanticipated difficult airway using an objective airway score versus a standard clinical airway assessment: the DIFFICAIR trial - trial protocol for a cluster randomized clinical trial. Trials. 2013;14:347.

21. Nørskov, AK. The Difficult Airway Management Trial: “The DIFFICAIR-Trial”. In: ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). 2000- [201500607]. Available from: URL of the record NLM Identifier: NCT01718561.

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REFERENCES 1. Belena J.M. et al. Journal of Clinical Anesthesia 2011; 23:456-460. | 2. Roiss M. et al. Poster presented at The American Association of Anesthesiologists Annual Meeting 15th -19th, Oct. 2011, Chicago. | 3. Sharma V. et al. BJA 2010; 105(2): 228-232. | 4. Whitacre W. et al. AANA Journal 2014; 82 (2): 101-107. | 5. Abdi W. et al. Acta Anaethesiol Scand. 2010; 54 (2): 141-146. | 6. Bernardini A. et al. Anesthesia 2009; 64: 1289-1294. | 7. Verghese C. et al.

Anesthesia and Analgesia 1996; 82: 129-133. | 8. Tretiak S. Anethesiology News 2009. | 9. Viernes D. et al. Anesthesiology News 2010; 9-13. | 10. Verghese C. et al. BJA 2008; 101 (3): 405-410. | 11. Jagannathan N. et al. Pediatric Anesthesia 2012; 22:759-764. | 12. Jagannathan N. et al Anesthesia 2012; 67(2): 139-144. | 13. Ferson D. et al. Anesthesiology 2007; 107:A592.

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JOSEPH LOSKOVE, MD Chief of Anesthesia Memorial Healthcare System Hollywood, Florida Dr. Loskove reports no relevant financial disclosures.

P

atients designated as “difficult to

intubate� (DTI) are more at risk

for losing their lives during both

emergency and routine surgeries.

Surprisingly, it is not the difficult airway itself that is most life-threatening; modern medical technology allows anesthesiologists to intubate even the most difficult of cases. Rather, deadly mistakes often occur in the process of identifying, communicating, and managing the existence of a patient with a difficult airway, especially among numerous providers.

As the chief of anesthesia at the Memorial Healthcare System, the third-largest public health system

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in the nation and highly regarded for its exceptional patient- and family-centered care, I drew an interesting and shocking parallel. How is it that UPS can tell us exactly where in the world our package is at any given moment, but at one of the leading hospitals in the area, we may not be aware of a patient’s DTI status if he or she is transferred from one department to the department next door? Memorial Healthcare did not have a proper system in place that ensured that the notation of a patient’s DTI status moved throughout the health care system along with the patient.

This article explains how Memorial Healthcare developed a standardized DTI protocol, how we implemented the protocol and achieved staff buy-in, and the resulting outcomes thus far. I will also share insights I have gained throughout the process, which I believe are relevant to other innovative health care initiatives being developed during this time of rapid change in the industry.

Challenges to Proper DTI Management The first and greatest challenge that health care providers face when dealing with a difficult airway is effective communication. In today’s landscape, a provider is likely to be part of a much larger health care system made up of multiple facilities that provide care to tens of thousands of patients every year. Traditionally, a patient’s difficult airway was only communicated to the anesthesia team; no effort was made to share this information with other parties, and there was no organized method to communicate the information to other providers.

In this traditional model, a patient’s DTI status is not likely to be effectively communicated in scenarios where the patient is moved to a different department or treated by multiple physician teams. This scenario is not uncommon in the operating rooms (ORs) and emergency rooms (ERs) of large hospital systems.

The second challenge is that the responsibility to intubate a patient outside of the OR often rests with nonanesthesia providers, such as emergency department physicians, intensivists, or trauma surgeons. This poses a challenge because these providers may not know that the patient has a difficult airway, may not be experienced with difficult intubations, and may not have the proper DTI equipment on hand.

The availability of advanced airway equipment (eg, video laryngoscopes, bronchoscopes, surgical airway equipment, and laryngeal mask airways) is a third challenge because such equipment is found inconsistently in ICUs and ERs. Because different facilities have different equipment outfits, an airway management system that has a record of success in one facility may be difficult to apply to other facilities, despite the fact that they appear similar on the surface.

Finally, the fourth challenge is that most health care systems use a combination of electronic and paper documentation. Thorough and consistent documentation is critical for DTI patients, especially for any future

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admissions to any facility in the system. For obvious reasons, regularly transferring information between electronic and paper systems quickly leads to errors.

Developing a DTI Protocol A comprehensive difficult airway management program streamlines the identification, communication, and management of difficult airways and thereby reduces life-threatening complications. As chief of anesthesia, I worked with my team of physicians, nurses, and other personnel—along with the Medical Executive Committee of the health care system—to create a series of processes that would address our concerns.

The first step in building an effective, formalized DTI protocol is defining a DTI patient in clear terms that a physician from any department can understand and use (Table). For our purposes, Memorial Healthcare defined a “DTI patient” as a patient for whom a conventionally trained laryngoscopist experiences difficulty with mask ventilation, difficulty with tracheal intubation, or both.

Using this definition, any physician from the Departments of Anesthesia, Emergency Medicine, Otolaryngology, Intensive Care, and Trauma may deem a patient DTI and indicate it on the patient’s chart.

Once the patient is identified as DTI using this consistent definition, the next step is communicating his or her DTI status to any provider who will be in contact with that patient. Traditionally, the DTI status is communicated by placing a sign over the bed or on the whiteboard in each room. However, because patients may travel throughout a facility for tests and procedures, that method is not sufficient. One of Memorial Healthcare’s successful solutions has been to place a bracelet on the wrist of each patient with “DIFFICULT TO INTUBATE” printed on it, which stays on the patient for the duration of hospitalization. In addition, a notation— “DIFFICULT TO INTUBATE”—is placed in the allergy section of the electronic health record (EHR), ensuring that this information is available for subsequent visits to any facility within the system. Thus, a DTI designation is treated like an allergy—just as a patient is banded with an allergy bracelet on admission to the emergency department or hospital, so too is a DTI patient banded on entrance into the health care system.

Although a DTI airway will likely pose a challenge fewer times in a patient’s life than, say, a penicillin allergy, treating patient education with the same importance that one treats allergy education has significant value.

An unknown DTI is truly a worst-case scenario for an anesthesiologist, so if a patient is informed that he or she has a difficult airway—due to an anatomic trait or past medical experience with neck cancer, etc—and can share that in preoperative conversations, an anesthesia team can proactively create a suitable plan for that patient. Memorial Healthcare established the practice of sending a letter to the patient, his or her family, and his or her caregiver to provide education on a patient’s DTI designation. Including a DTI designation in an EHR takes the onus of communicating the status

off the patient or the caregivers, which is particularly important in emergency situations.

In nonemergency situations, ensuring that the patient is fully aware of his or her DTI designation (just as if he or she had an allergy) adds another opportunity for the designation to be communicated, which is especially valuable for health systems that have not yet finalized their DTI system.

Once a system is in place to correctly identify a patient as DTI and band him or her to ensure that the designation is communicated, steps must be taken to obtain the necessary equipment. This can be done by introducing standardized DTI carts throughout all facilities in the system, including the ORs, ERs, and ICUs. The new standardized DTI carts are similar to a “code” cart—the carts at all facilities are stocked identically, and when opened are returned to a centralized location to be cleaned or sterilized, restocked, and resealed.

Implementing a New Procedure One of the numerous lessons that I learned throughout the process of implementing a DTI protocol is that the application of an idea requires the most work by far, and is the most important piece to get right. A great idea without thorough and lasting implementation is of no use.

To ensure that our implementation was solid, we developed a comprehensive plan to distribute the new protocol throughout the organization. Once the new protocol was approved by the various governing bodies at the hospital, I set about introducing the protocol to all stakeholders and educating them on DTI risks.

Many providers outside of the ER and OR are not familiar with difficult airways and the danger they pose, so providing some context to the new protocol was critical as well. I attended meetings for nurses, surgeons, and doctors in other departments in an attempt to educate as many staff members in the hospital as possible.

After the initial introductory sessions, I developed continuous educational sessions throughout the year and established an annual check-in to monitor progress. This training also became a standard part of the onboarding process for new doctors and nurses. This diligent educational effort has paid off, as the DTI protocol is now engrained into the culture at Memorial Healthcare.

When the patient was transferred to another Memorial Healthcare hospital for urgent cardiac catheterization, a nurse noted the DTI designation in the allergy section of the patient’s EHR and placed the DTI wristband on the patient. Although this step should have been completed in the first institution where the patient was initially designated as DTI, the extensive educational efforts that took place raised the level of awareness of nursing staff across the hospital and helped the nurse in the second facility to recognize the DTI risk.

This outcome was a direct result of our efforts to familiarize all staff with the new DTI protocol.

After undergoing a successful cardiac catheterization and stabilization, the patient was transferred to a third Memorial Healthcare hospital for coronary artery bypass graft surgery. In the preoperative holding area, the anesthesiologist noted the DTI wristband and brought the new DTI cart into the OR. Upon induction of anesthesia, the patient’s airway was found to be challenging, but the anesthesiologist was able to use the equipment available on the DTI cart to successfully and atraumatically intubate the patient. Without the DTI protocol, the DTI cart equipment would not have been so readily available, and that unavailability would have caused delays that could have had negative effects on the patient’s well-being. The patient underwent surgery and was discharged home in good condition.

Implementing this protocol can address the many challenges that a difficult airway presents to hospitals and health care systems. As large networks of hospitals become more common, it will be crucial for physicians, nurses, and technicians to be educated in effective DTI communication methods such as the one instituted at Memorial Healthcare.

Lessons Learned To conclude, I’d like to highlight some lessons that were learned while working to establish a DTI protocol at Memorial Healthcare. These lessons are particularly relevant in today’s health care environment where we are all trying to deliver quality care at lower costs.

Table. Steps To Implementing a DTI Communications Protocol

Process and Outcome Improvements

• Define the DTI patient

The new DTI protocol described in this article was introduced at Memorial Healthcare in February 2012, and began to deliver results almost immediately.

Shortly after the program’s introduction, a patient was admitted to the ER of one of the Memorial Healthcare hospitals with an acute myocardial infarction and required intubation. The ER physician encountered difficulty, and the anesthesia team was asked to assist.

Subsequent intubation was successful, and the ER physician then wrote an order in the EHR deeming the patient to be DTI.

• Disseminate DTI status - Use a DTI bracelet - Make a notation in the allergy section of the electronic health record - Send a letter about DTI status to the patient or caregiver • Introduce standardized DTI carts throughout the health care system DTI, difficult to intubate

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The first major take-away is that innovative ideas do not need to be complicated. Sometimes the most impactful ideas are also the simplest and the cheapest.

With many hospitals looking to innovate on a budget, the DTI protocol is a useful example of the influence of small, standardized procedural changes and heightened awareness about an issue.

A related issue is that hospital personnel should not feel intimidated or helpless to offer suggestions for process improvement. Just as in any large organization, it can be hard to be innovative in a hospital setting—the bureaucracy is daunting, schedules are packed, and staff are focused on patient care first and foremost—but it is important to look for the everyday inefficiencies that could be fixed with a simple solution. The staff on the front lines—especially doctors, nurses, and technicians— are uniquely positioned to identify the small problems that constantly drain efficiency, safety, and profitability from the hospital. When front-line staff share these process problems with management, it becomes easier to create solutions for the hospital’s real productivity challenges. After I gave my first DTI presentation, Memorial Healthcare’s chief of medicine teasingly asked why no one had proposed this solution before. This goes to show that if you have an idea, speak up.

The second key take-away was the enormous amount of work that must go into implementation of a new practice. A new protocol must be tirelessly promoted to become a reality. In hindsight, you will almost always find that having the idea in the first place was the easiest part. The countless educational sessions and training efforts that went into turning that idea into a reality may have seemed repetitive, but that is what it took to ingrain the DTI protocol into the culture at Memorial Healthcare.

That hard work has certainly paid off, and I believe that this lesson can apply to change initiatives as a whole.

A third lesson that the DTI protocol highlights is the ways in which EHRs can improve patient safety by facilitating faster and easier communication between physicians and departments. In the example I shared, the nurse in the second facility was able to see the patient’s

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chart in real time—thanks to the EHR—and aptly spot and manage the DTI designation. This instant exchange of information may have saved the patient’s life.

Lastly, the fourth lesson is perhaps the most important of them all—the power of collaboration. The success of the DTI protocol hinges on cooperation across all levels and departments of the health care system. A successful implementation should be a powerful example of how cross-departmental communication affects patient care in a hospital or health care system. Ten years ago, almost all hospitals had their departments working in silos, but there is a growing movement to break down the barriers that insulate physicians in their own departments and specialties.

Increasingly—whether in anesthesiology, radiology, or critical care—health care leaders are finding that working collaboratively and acting in a consultative capacity with their peers improves patient care, safety, and hospital efficiency. Cross-departmental process improvements are a boon for hospital finances as well, because they ensure that time and resources are not wasted with duplicated efforts.

Difficult airways are not especially dangerous if physicians have a proper warning. The danger lies in the failure to communicate a DTI status as the patient moves throughout a health care system. Through simple, standardized process changes, steadfast implementation, and interdepartmental cooperation, Memorial Healthcare was able to largely eliminate this danger.

My hope is that we will use this model for other patient safety initiatives throughout the health care system, and that other hospital leaders might reevaluate their DTI protocol and incorporate these tactics or others that make the hospital safer for DTI patients. I encourage other hospital leaders to use our DTI implementation model as a rubric for their own process improvement efforts.

Joseph Loskove, MD, also serves as a regional medical director for the anesthesia division of Sheridan Healthcare, a provider of outsourced physician services.

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Airway Management Roundtable: Seven Questions

S

ix anesthesiologists from around the world were asked to o answer a 7 questions, whose general theme

is airway management. D. John n Doyle, oy MD, PhD, picked the members o off o our urr expert panel and wrote all the q questions, st ons ns to which he supplied his own responses.

D. JOHN DOYLE, MD, PHD

PROF. GIULIO FROVA, MD

Chief of General Anesthesiology, Anesthesiology Institute, Cleveland Clinic Abu Dhabi, United Arab Emirates.

Qualified University Teacher in Anesthesiology and Intensive Care, University of Milan, Italy.

Staff Anesthesiologist at the Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, where he serves as Professor of Anesthesiology at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University.

WILLIAM ROSENBLATT, MD

Dr. Doyle is a member of the Anesthesiology News advisory board.

Director of Anesthesia for Otolaryngology, Yale-New Haven Hospital, New Haven, Connecticut.

Professor of Anesthesiology and Surgery, Yale University School of Medicine,

BASEM ABDELMALAK, MD Associate Professor of Anesthesiology, Director of Anesthesia for Bronchoscopic Surgery, and Director of the Center for Sedation, Departments of General Anesthesiology and Outcomes Research, Cleveland Clinic, Cleveland, Ohio.

President of the Ohio Society of Anesthesiologists.

RICHARD COOPER, MD, FRCPC Professor at the University of Toronto, Director of the Anesthesia Airway Fellowship, Department of Anesthesia, Toronto General Hospital, Toronto, Ontario, Canada.

Immediate past president of the Society for Airway Management.

JOAN E. SPIEGEL, MD Assistant Professor, Anesthesia and Critical Care Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts.

Dr. Spiegel is a member of the Anesthesiology News advisory board.

Drs. Abdelmalak, Doyle, and Spiegel reported no relevant financial disclosures.

Dr. Cooper disclosed that he is the unpaid chairman of the Scientific Advisory Board of Verathon Medical.

Dr. Frova disclosed royalty agreements with Cook Medical (as inventor of the Frova Intubating Introducer) and Teleflex Inc (as the inventor of the PercuTwist and EasyCric).

Dr. Rosenblatt disclosed that he is an uncompensated advisor to Ambu.

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With the advent of inexpensive video laryngoscopy, will there still be a place for direct laryngoscopy a decade from now?

Doyle: Yes. As an analogy, the fact that automatic blood pressure machines are readily available does not mean that nurses and doctors should not be taught manual blood pressure measurement via auscultation of Korotkoff sounds.

Frova: I would say that inexpensive video laryngoscopes (VLs) do not exist today, but a few of them are less expensive than others because they are partially disposable. In 10 years, many technological improvements may happen, but my feeling is that direct laryngoscopy not only will have a place in the anesthesiologist’s armamentarium, but also that its use must be taught and expertise acquired. Let’s look back to the advent of sophisticated and expensive ventilators that did not eliminate the need and utility of a trivial Ambu bag (in an emergency, in a helicopter, in an ambulance, and in developing countries). So, I am almost sure that the MAC laryngoscope will still be used by anesthesiologists for a long time to come.

Abdelmalak: Yes, direct laryngoscopy will still play a role due to its long track record of utilization, familiarity, success, and safety, in addition to its simplicity and low cost. With that in mind, the role (ie, its market share) may diminish if video laryngoscopy technology and the price of disposable blades for it become much cheaper than they currently are.

Cooper: I don’t believe that inexpensive video laryngoscopy has arrived. When and if it does, direct laryngoscopy will become a relic. I think that we are witnessing a divergence of approaches; some manufacturers offer more sophisticated equipment, increasing cost, and limiting market, which in turn increase cost. Other companies are trying to cut costs by sticking to basic needs.

If the right balance can be found, it will encourage more widespread use of video laryngoscopy, increasing the competition and lowering production costs.

Once this occurs, users will experience the benefits and few will want to revert to direct laryngoscopy. Unfortunately, less robust construction may lead to patient injury and equipment malfunction, and slow the use of

video recording for clinical documentation and quality improvement.

Spiegel: Perhaps not in the traditional sense. The best VL is yet to be designed, but we are getting closer. I think the best VL is one that has the traditional direct viewing angle—the 30-degree MAC 3. This direct-view angle blade still allows for bougie placement, a critical advantage of the direct-view approach.

Rosenblatt: For the last 10 years, I’ve been predicting that direct laryngoscopy would be gone from the operating room in 5 years. Obviously, I was very wrong.

However, the reason for my error has changed during the last decade. At first, video laryngoscopy was not as widely adopted as I expected because, I believe, it was misused by clinicians, resulting in its full potential not being realized. When handed their first VLs, most clinicians looked at the technique as “direct laryngoscopy plus.” In other words, video laryngoscopy was not appreciated as a completely new way to visualize and then instrument the larynx and trachea. Most clinicians treated video laryngoscopy as a helpful adjunct to delivering tracheal tubes the way we did with direct laryngoscopy. It later became apparent, primarily through experience and teaching by organizations such as the Society for Airway Management, that we needed to develop a whole new set of skills for successful video laryngoscopy.

The second barrier was cost. The early VLs were not cost-effective when compared with direct laryngoscopy combined with simple adjuncts, such as the gum elastic bougie. Now, with the availability of low-cost CMOS (complementary metal-oxide semiconductor) imaging technology, the expense of video laryngoscopy has plummeted.

Therefore, in answer to this question, I would say yes. I believe that within a decade most routine laryngoscopies will be performed with some sort of video technology, especially in the environment of the operating room. There will be venues worldwide where direct laryngoscopy will survive, not simply because of cost, but also due to lack of technology maintenance.

One might argue that if we were to do one thing to make direct laryngoscopy more successful in marginal cases, then that would be to emphasize to our trainees the use of simple, inexpensive airway introducers (eg, “gum elastic bougies”). Do you agree that they are underused?

Doyle: Absolutely. Use of an airway introducer and knowing how to position the obese patient for ease of intubation (via the “head-elevated laryngoscopy position”) are two of the simplest, most inexpensive techniques available to make tough laryngoscopy easier.

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Frova: I agree, especially with the first part of the question. I think that cheap, simple, ergonomic, and effective devices will always have a place in airway management, and they remain very useful for teaching novices how to use a bougie. Combining direct laryngoscopy with a

tracheal introducer (bougie is a bit of a generic term) is the simplest and most effective technique to cope with a limited view of the laryngeal inlet and vocal cords.

I also agree with the second part of the question.

According to some literature and sparse sales data,1 last year bougies were used 1 million times all around the world. Supposing they are needed in only 3% of intubations, what is 1 million uses in the world when in Italy alone subjective approximations find that 2.5 million intubations are performed every year? They are clearly underused. I have no objective data, but I have the feeling from our airway management courses that 50% of colleagues ignore indications and their correct use.

Abdelmalak: I totally agree that they are underused, and together with direct laryngoscopy, provide an economic alternative to other, more expensive technologies used in managing certain difficult airways—such as those described as having an “anterior larynx” or high Cormack-Lehane grade. Especially when such a situation is unanticipated, there will be no need for a second laryngoscopy or a different laryngoscope; just add the bougie and proceed.

Cooper: I agree that they are less often used in the United States compared with the United Kingdom and Australia. However, I would also argue that we should not acquiesce to blind intubation by pushing the limits

of direct laryngoscopy and attempting to intubate a larynx that we cannot see (ie, Cormack-Lehane grade 3 or 4). Absent an emergent intubation, I would prefer to use a technique that enables visualized intubation, such as video laryngoscopy. At least in the developed world, we should neither encourage nor defend the continuation of blind intubation. Multiple attempts are associated with increasing complications, which are difficult to justify by the increased cost.

Spiegel: Definitely underused. The Cormack-Lehane classification system is based on the decision tree to use or not use the bougie. With direct-view video laryngoscopy we can still use this learning approach, which I believe is excellent, to pass on to the residents.

Rosenblatt: I would agree with Dr. Doyle that one of the most simple and cost-effective adjuncts that we can advocate to improve success with direct laryngoscopy is use of the airway bougie. I also believe that we need to emphasize the practice of making our first attempt at laryngoscopy the best attempt, that is, positioning the patient correctly, making sure that we have correct working equipment at hand, and being confident that we’ve done a thorough preoperative evaluation.

Although we perform laryngoscopies and intubations many times a day, we should never take it for granted and always have thoroughly prepared ourselves and our patients for success.

There are so many published difficult airway algorithms out there now, coming from America, Canada, Britain, Italy, Germany, China, etc. How does one choose between competing algorithms other than to choose on the basis of personal nationalist leanings?

Doyle: Nationalist leanings work for me. However, for a more nuanced answer, please read the chapter on this very topic by Sorbello and Frova in our upcoming book.2 Frova: Actually, 8 guidelines on airway management have been published during the last 20 years, but I do not think there is competition among them. It might be wise to read all these documents, but apply your own country’s national guidelines to daily practice. It is redundant to underline that guidelines are only suggestions, and every anesthesiologist has the ability to interpret them, without rigidity to a dogmatic mandatory assumption, and adapt them to a specific clinical scenario, taking into account that if he or she chooses to act differently from suggested guidelines, then he or she should be able to support and justify the choice.

What is mandatory is that the fundamental goals of a suggested guideline should be shared and accepted.

Abdelmalak: Although difficult airway algorithms are mostly meant to be referred to as “guidelines” rather

than standards of care, they are often considered as such. Many times individuals place emphasis on whether the guidelines have been followed when a difficult airway scenario is encountered. Perhaps one’s own national difficult airway algorithm should be considered when developing personal or institutional policies or practices.

However, reviewing and studying other countries’ algorithms can be extremely helpful and may guide clinicians to better implement their own country’s algorithm. For example, the US difficult airway algorithm calls for making certain decisions as the initial step in difficult airway management, such as whether a patient should be intubated awake or after induction of anesthesia, and so forth. The Canadian difficult airway algorithm nicely reviews some of the circumstances and findings that should be considered in making such a decision.

Cooper: For the most part, the guidelines are based on low-level evidence, and at best, represent a consensus of opinion of experts in the area. The content of

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the various guidelines is not fundamentally different, but it uses different terms and varies in specific recommendations. For example, all agree that limiting the number of intubation attempts is a worthy objective: The Canadian Airway Focus Group (CAFG2) recommended no more than 3; the Difficult Airway Society guidelines recommended no more than 4; and the American Society of Anesthesiologists (ASA) guidelines recommend limiting the number of attempts without specific guidelines. It defines a “difficult intubation” as one that cannot be achieved despite “multiple attempts.” Another example concerns recognition of failed intubation/failed ventilation. CAFG2 elected to place emphasis on failed oxygenation, the ultimate objective of ventilation and objectively measurable.

In the final analysis, when it comes to judging performance, an anesthesiologist is likely to be judged by a group of peers who are likely evaluating adherence to national practice guidelines. However, practice “guidelines” are just guidelines and are intended to inform clinical judgment. If wisdom is recognized in the guidelines from another national society, there is nothing to prevent its incorporation into a clinician’s practice.

Spiegel: I would have trouble answering that since I am not aware of the differences. I still look to the ASA guidelines. If the algorithm incorporates too many branches, it becomes less useful.

Rosenblatt: When we drill down to their cores, we see that all the algorithms are essentially the same. Certainly

they all have identical goals, which are oxygenation and ventilation of the patient.

Cultural differences will often help to define which algorithm is better for each clinician, and that is appropriate. For example, in the case of the ASA algorithm, there are suggested pathways that may be satisfied by any number of techniques and devices, whereas the algorithms coming from Europe tend to encourage less variability on the basis of the individual clinician and suggest specific devices. However, this highlights another issue: Not only do we have algorithms supplied by societies and organizations of different countries and cultures, but also by different disciplines. For example, you may be involved in an airway resuscitation that includes emergency medicine physicians, intensivists, and nurses. A vital question is, “How do these different disciplines communicate and meld their chosen algorithms?” A resource that brings all of these algorithms together is called The Vortex Approach. The Vortex Approach, developed by Drs. Nick Chrimes and Peter Fritz,3 is a simple, visual, cognitive aid that helps to organize airway resuscitation around the 3 minimally invasive techniques (face mask, supraglottic airway [SGA] ventilation, or tracheal intubation by any means) and percutaneous emergency airway access in an easy-to-communicate manner.

Not only does this cognitive aid guide the team and communicate success and failure, but it also promotes the advancement of care and prevents perseveration on any one tool or technique.

Imagine that a patient’s airway is truly lost and the patient is deeply cyanotic.

A surgeon arrives on the scene and wants to do a tracheostomy, instead of a cricothyrotomy, to rescue the airway. Bradycardia is setting in. What should you say or do?

Doyle: It’s time for a cricothyrotomy, not a tracheostomy; tracheostomies just take too long. (One reason that tracheostomies take longer than cricothyrotomies is that tracheostomies are usually performed between the second and third tracheal rings, whereas cricothyrotomies are performed through the more easily identifiable cricothyroid membrane.) For a video on how to perform a 55-second cricothyrotomy, go to www.youtube.com/watch?v=I6wodB2S0uc. Notice how use of an airway introducer makes the procedure look so easy.

Frova: The clinical situation described, of cyanosis and bradycardia, does not permit any waste of time. An urgent tracheostomy needs 4 minutes or more to be completed and allow for oxygen delivery, in the best surgical hands. I would tell the surgeon to perform a surgical cricothyrotomy in 1 minute, or, preferably, I would perform it myself. The surgical cricothyrotomy may be performed with elementary devices (ie, scalpel-stylet-small size tube or scalpel-bougie-tube) or

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be percutaneous, although it would be better if it was done using a Seldinger ergonomic set. A percutaneous cricothyrotomy could be performed in less than 40 to 50 seconds from packaging opening to oxygen delivery, as long as the physician has basic knowledge and expertise.

Abdelmalak: What I would say or do in such a scenario depends on what specialty the surgeon belongs to and his or her skill level. As the situation indicates, this is a very emergent situation that requires swift intervention.

Surgeons are best in performing surgical airways, especially if they are otolaryngologists. In that case, I would not utter a word and allow them to do what they do best. On the other hand, if a different-specialty surgeon who does not have the experience or knowledge of airway management is present, I may go ahead and temporize the situation with percutaneous transtracheal jet ventilation, with which I’m most familiar, or perform a cricothyrotomy (Seldinger’s technique), with which I’m

also familiar. I would then reevaluate to decide whether a tracheostomy is still needed, and determine who should perform it and the best way to accomplish that.

Cooper: I think that would depend on the surgeon, but generally I would defer. I have witnessed ear, nose, and throat surgeons perform an emergency tracheostomy far faster than I could do a cricothyrotomy.

Spiegel: That depends on what equipment we have available and the expertise of those present. An open or Seldinger cricothyrotomy is preferred over open tracheostomy for a few obvious reasons, and I would hope to convince my colleague of that approach since I am comfortable performing that procedure and could assist, if needed. Emergent tracheostomy usually ends in a bleeding disaster if done emergently.

Rosenblatt: First of all, I wouldn’t be waiting for a surgeon to arrive. In question number 3, I spoke briefly about The Vortex Approach. The Vortex is a cognitive aid to help guide you through the techniques that are used in emergency airway management. If we drill down on the ASA’s algorithm, only 4 techniques are available for airway resuscitation: face mask ventilation, supraglottic device ventilation, tracheal intubation, and percutaneous emergency airway access (PEAA). What I find so useful about The Vortex Approach is that, depending

on the clinical situation, it encourages no more than 3 attempts at each 1 of the 3 noninvasive techniques.

After 3 attempts at each—or possibly less depending on the clinical situation—the team rapidly progresses to a PEAA. If you carefully consider this approach, you realize that PEAA may be encouraged before the oxygen saturation has fallen or before the patient becomes cyanotic. You are now performing PEAA in a patient who is likely to have a better outcome.

Getting back to your question, let’s assume that a surgeon is at the bedside when the need for a surgical airway arises. My encouragement of the surgical approach depends on the skill of that surgeon and the airway at hand. If I’m working with an otolaryngologist, who I believe has competence in rapid tracheostomy, I would certainly not interfere with his or her attempts.

On the other hand, if I am working with a surgeon who is less skilled or less confident in his or her skills, I would prepare and encourage that surgeon to perform transcricothyroid membrane PEAA. Also, very importantly, I would continue attempts to manage the airway from above, as long as I could avoid disrupting the surgical attempt. That is, I would continue my efforts at mask ventilation, supraglottic ventilation, and possibly tracheal intubation. There is no reason why I should abandon what I am doing from above while a second team is working to save the patient from below.

Has the popularity of video laryngoscopy had a negative impact on the use of fiber-optic intubation? What is your experience?

Doyle: This appears to be the case, but I cannot offer supporting data. Certainly, I have encountered many cases in which the clinician judged the airway to be too difficult for direct laryngoscopy but for which fiberoptic intubation (FOI) was seen as unnecessary, given the availability of video laryngoscopy.

Frova: I suppose that sales of flexible fiber-optic instruments might have been influenced by the huge addition on the market of VLs and companies’ pressure, but many of these companies produce both devices. I think that use of a flexible fiber-optic endoscope is mandatory in many nonemergent clinical settings (such as in the case of a very limited mouth opening, or for thoracic anesthesia, etc), and such an instrument is mandatory in the airway cart. In my personal experience, the VL noticeably reduced but did not abolish the use of a flexible fiber-optic endoscope in an otorhinolaryngology theater and, with some exceptions, the request for FOI in general surgery. Obviously, one could not substitute a flexible scope in the setting of thoracic anesthesia. It is important to remember that, if compared with FOI, the video laryngoscopic procedure is not so easy to perform with topical anesthesia; it requires relaxation and adequate levels of anesthesia.

Abdelmalak: Yes, it seems that practitioners prefer using the VL as opposed to the flexible fiber-optic scope in many anticipated and known difficult airway scenarios. Thus, the number of flexible FOIs performed has decreased, which may result in diminishing practitioners’ skills in performing such a procedure (awake or asleep) if they have had some experience already, or never advancing their skills if they are still on the learning curve.

As for my own experience, I remain a flexible fiberoptic scope enthusiast. Realizing the caveat presented above, I make a conscious effort to continue to use or even increase fiber-optic use to maintain and advance my own skills, and to teach trainees as well. Such a skill becomes handy in managing many complex airways secondary to the head and neck cancers that I deal with on a daily basis. Such airways require the versatility of the flexible fiber-optic scope versus the VL and make for a great opportunity to train the next generation of anesthesiologists.

Cooper: My impression is that far fewer bronchoscopic intubations are being performed, and I would expect that the skill will likely deteriorate. J. Adam Law et al,4 however, recently reported no decline in the number of awake bronchoscopic intubations between 2002 and

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2013 (averaging 1.06% of intubations), despite a significant increase in the use of video laryngoscopy. On the other hand, Wanderer and colleagues at Vanderbilt5 observed a significant decline and corresponding increase in the number of awake bronchoscopic and video laryngoscopic intubations, respectively.

Spiegel: Yes, it definitely has reduced the use of awake FOI. We try to do asleep FOI electively for the rare cases of which we need to know the equipment for awake cases.

Rosenblatt: The literature provides a mixed opinion on this topic but offers insight into concepts of difficult airway decision-making and management.

In 2013, Wanderer et al5 published a longitudinal, uncontrolled study that showed decreasing use of FOI techniques as their practice acquired more VLs. Close examination into their methods reveals that this group equated the use of the fiberscope with the use of an awake intubation technique. Awake intubation is often elected when a patient’s airway is perceived to be

difficult to manage, although it is possible that routine airway management would have been adequate. They interpret their data as evidence that fewer difficult airways were encountered. In response to this report, Caldiroli et al6 make the comment that Wanderer’s data do not necessarily reflect a reduction in difficultto-manage airways but rather a reduction in patient airways perceived as being difficult: Availability of and experience with video laryngoscopy gave the operator more confidence in light of the preoperation evaluation findings. Counter to this, J. Adam Law et al4 found no decrease in the use of the flexible scope over a similar time period.

What I do believe, however, is that there can be a dangerous tendency for those who are uncomfortable with techniques such as awake intubation to default to the use of video laryngoscopy. In most cases, patient management will be successful. However, in some number, this approach will result in catastrophe, as was noted in the 4th National Audit Project (aka the NAP4) study.7

What is your favorite SGA, and why do you like it over the others?

Doyle: I very much like the i-gel (Intersurgical). The seal that it provides is excellent; you can intubate through it; it has both a gastric port and a bite block; and cuffpressure issues are nonexistent. Plus, it has got me through some very tough scrapes.

Frova: LMA Classic (Teleflex) was my first extraglottic device, and for a long time remained my favorite. Years later, I switched to the LMA ProSeal (Teleflex), which remains my favorite today. Many different devices are on the market now, and this can be confusing for naive users. My advice would be to prioritize second-generation devices, such as the ProSeal or other similar devices, with proven efficacy and safety. As an alternative, choose any device that you are familiar with, which grants a good seal and combined fiber-optic basic/ advanced access.

Abdelmalak: The i-gel; it has a large lumen even in the smallest adult size of 3, thus allowing for flexible bronchoscopy and/or intubation through it. It is easy to insert, has a built-in bite block, esophageal access, and a good seal around the larynx, which allows for more effective positive pressure ventilation. It is almost onesize-fits-all for adults, since size 4 fits patients 50 to 90 kg in weight. There is a lack of aperture bars such as those in the original LMA, which makes it easier to perform flexible bronchoscopy and/or intubation through it; however, it still has the epiglottic elevating bar. It is not foolproof and still does not work for some patients (because of difficulty inserting/seating, excessive leakage, or ineffective ventilation), but when that happens, I will either try a different brand of SGA or switch to

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endotracheal intubation.

Cooper: I have different preferences for different circumstances, but generally I rarely use devices that don’t permit gastric decompression or provide highseal pressure.

Spiegel: LMA Fastrach (Teleflex). It allows for intubation and simultaneous ventilation. It’s an ingenious device. For nonintubation, I prefer the LMA Supreme (Teleflex). I also favor the i-gel and LMA ProSeal.

Rosenblatt: There is a well-known quip that makes its rounds in medical schools: The most important part of the stethoscope is the part between the earpieces.

I believe the same is true with most of our airway equipment and techniques. All of the available SGAs are capable and have been developed by imaginative minds with the backing of trial and error and research.

The most important part of the SGA device and what separates one from another is the hand that is inserting it into the mouth.

On the other hand, there have been certain design advancements that separate devices and influence my choice. First, I believe that virtually all SGAs in use today should be of the second-generation type, that is, SGAs with gastric access, the facility for determining position, and the capability of achieving higher interairway pressures. I also prefer SGAs of the perilaryngeal sealer variety, that is, those that have a cuff or other solid structure that completely surrounds the larynx, as opposed to those that block the hypopharynx from above and below.

What is your favorite VL, and why do you like it over the others?

Doyle: In 2003, I first used the GlideScope (Verathon) and have been an enthusiastic supporter ever since.

Above all, I like the image quality, but it is not without drawbacks: It is more expensive than I would like and not portable enough to be able to keep with you at all times. That said, the GlideScope has got me through so many difficult airway situations over the years that I must acknowledge a debt of gratitude.

Frova: This is not an easy question! Of the many devices that are available, I like specific features of several devices, but if I need to express a general preference, I would say the GlideScope due to long personal experience. As a retired anesthesiologist, I am not up-to-date on the recent developments on VLs. Abdelmalak: The McGRATH MAC (designed and manufactured by Aircraft Medical, and distributed by Covidien). It is lightweight, portable, the screen is of reasonable resolution, and the blades are low profile, leaving room for introducing the endotracheal tube in small-mouth patients. Moreover, oftentimes one can intubate without needing a stylet, which further adds to its safety compared with other available VLs. Finally, the disposable blades are cheaper than some of the other competing brands.

Cooper: My bias favors the GlideScope, but I also have far more experience with this device. The new Titanium series is robust, does not fog, is available in a range of sizes, can be placed into relatively small mouths, provides an excellent glottic view, and makes recording and video review easy. However, there are many excellent products, including some decent single-use devices for the occasional user.

Spiegel: I favor the VLs that have both direct and indirect capabilities. There are 3: C-MAC (Karl Storz), GlideScope Direct, and McGRATH MAC. All are excellent for using the bougie, if necessary. These are ideal devices.

Rosenblatt: As I answered above, I believe that the most important variable in VL design is the hand that is holding it. I don’t have a preference among the various VLs available today. I think they are all highly capable, and now that many have a variety of angulated blade options, virtually all achieve the same results. The clinician who chooses any VL and treats it as “direct laryngoscopy plus” will get into trouble. Apart from experiencing more failed tracheal intubations, they will likely cause more trauma to the patient’s airway.

The nonchannel VLs introduce a “blind spot” into the process of tracheal tube placement. Once the VL has been positioned in front of the larynx, the introduction of the trachea tube is “blind” until its distal end is within the scope’s visual field. There have been 11 or more published case reports of trauma to soft tissues due to this. Any new medical technology will also introduce new morbidities and the need for techniques to avoid those morbidities. Such is the case for video laryngoscopy, as described. Simply revising your technique away from “direct laryngoscopy plus” can avoid these morbidities.

Some clinicians argue that the channel-type VL is less traumatic and a better technique, but the channel-type VL reduces the independent maneuverability of the tracheal tube within the airway. For some clinicians and for some clinical situations, this will be an inappropriate choice, so I truly don’t have a favorite VL. On a caseby-case basis, my choice will depend on the patient’s anatomy and my experience with the various devices.

References 1.

Evans H, Hodzovic I, Latto IP. Tracheal tube introducers: choose and use with care. Anaesthesia. 2010;65(8):859.

2. Doyle DJ, Abdelmalak B. Clinical Airway Management: An Illustrated Case-Based Approach. New York: Cambridge University Press. In press.

3. For more information about the Vortex concept, see VortexApproach.org.

4. Law JA, Morris IR, Brousseau PA, et al. The incidence, success rate, and complications of awake tracheal intubation in 1,554 patients over 12 years: an historical cohort study. Can J Anaesth.

2015;62(7):736-744.

5. Wanderer JP, Ehrenfeld JM, Sandberg WS, et al. The changing scope of difficult airway management. Can J Anaesth.

2013;60(10):1022-1024.

6. Caldiroli D, Orena E, Cortellazzi P. Reflections on the changing scope of difficult airway management. Can J Anaesth.

2014;61(1):84.

7.

Cook TM, Woodall N, Frerk C, et al. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth.

2011;106(5):617-631.

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Supraglottic Airways: Their Evolution as Tracheal Tube Introducers JAMES DUCANTO, MD Quality Officer Aurora St. Luke’s Medical Center Milwaukee, Wisconsin The author reported no relevant financial disclosures.

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nesthesiologists and emergency medicine providers encounter difficult endotracheal intubation

in up to 6% of cases.1-3

The American Society of Anesthesiologists, which first developed guidelines for management of the difficult airway in 1992 and revised them in 2003, included the use of the laryngeal mask airway (LMA), a specific type of supraglottic airway (SGA), as a rescue device for ventilation and as a conduit for insertion of an endotracheal tube (ETT), either blindly or guided by a fiberoptic bronchoscope (FOB).4

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Much has been written on SGAs over the past 20 years, mostly to extol their virtues as devices to be used in lieu of endotracheal intubation during elective surgery and as rescue ventilation in the setting of difficult airway management.

Since the advent of the intubating LMA Fastrach (Teleflex) in 1995, SGAs have also assumed the role of rescue intubation devices, a role that has expanded as a new generation of fiber-optic endoscopes, both traditional and video-enabled, has proliferated in the medical marketplace.

This article will discuss the recent evolution in the United States and international marketplaces of clinically available SGAs that serve as intubating conduits— that is, as true airway problem-solving devices. This article will also detail 2 methods of visualized tracheal intubation through a specific brand of SGA in order to illustrate the techniques needed for guided intubation through SGAs.

Figure 1. LMA Fastrach.

History Archie Brain, MD, devised the LMA Fastrach (Teleflex; Figure 1) in 1995, as a tool to support ventilation and intubation. This particular SGA has since accumulated one of the largest bodies of literature to support its effectiveness and use in anesthesiology, emergency medicine, critical care, and pre-hospital medicine.

Devised as a tool that can effectively deliver a proprietary, soft-tipped tracheal tube using a blind technique, the LMA Fastrach has a proven track record. Although the blind method for the LMA Fastrach is easy to learn and implement, the consensus among physicians and allied health care workers who practice airway management has today evolved to the point where the use of imaging systems to guide the tracheal tube intubation is preferred.

Utilizing visualized guidance through an SGA obviates the need to learn specific techniques and maneuvers to enable blind intubation with a given SGA. A recently published theoretical article concerning inwater and underwater resuscitation explores the use of a fiber-optic stylet-visualized intubation through an SGA in a simulated setting, with the endoscopist in scuba gear immersed in the water-filled section of a special research hyperbaric chamber to a depth of 20 m.5 Indeed, the endoscopy system can be used to comprehensively set the stage for systematic examination of the SGA position within the patient’s airway, readjustment of the SGA should that be deemed necessary to align its ventilation channel with the larynx, and guidance of the tracheal tube through the ventilation channel of the SGA. Utilization of a bronchoscopic port adapter with a flexible bronchoscope can furthermore permit the endoscopist the option of continuous ventilation during the intubation attempt, as the ventilation circuit can continue to deliver positive-pressure ventilation breaths throughout the endoscopy.

Figure 2. Demonstration of the function of a gastric drainage port on an LMA Supreme in a mannequin modified to flow simulated vomit using wireless radio control.

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There are several commercially available SGA devices that represent the state of the art with regard to the ability to provide a conduit for visualized, guided intubation. Many of these SGA devices are categorized as second-generation SGA devices that possess the ability to divert passive regurgitated material away from the laryngeal inlet through dedicated guide channels or balloon-tipped catheters. The second-generation SGAs with tracheal-intubating capability do indeed represent the state of the art of SGA-based tracheal intubation strategies, as these devices provide a margin of safety in patients in whom fasting is either not effective to prevent retention of stomach contents or, conversely, in patients who are not fasted prior to airway management, such as patients facing emergent airway management before emergency surgery.

To demonstrate the concept and function of a gastric drainage port, Figure 2 shows a geyser of simulated

All images courtesy of James DuCanto, MD

Current Tracheal Intubation–Capable SGA Systems

vomit emerging from the gastric drainage port of an LMA Supreme (Teleflex) second-generation SGA in an airway management training mannequin that has been modified to flow simulated vomit using wireless radio control (author’s unpublished research).

The expanding role of second-generation SGAs in resuscitation and emergency airway management is an important topic in pre-hospital medicine and emergency medicine. Stone et al noted that the incidence of regurgitation during cardiopulmonary resuscitation is as much as 4-fold greater in patients managed with the traditional bag-valve-mask as in those managed with an LMA.6 Of relevance to anesthesiologists, multiple published case reports exist of the use of the LMA as an alternative airway device during cesarean delivery, including a large series of 3,000 cases by Halaseh et al that used the LMA ProSeal (Teleflex), a second-generation SGA.7

Description of Selected Intubation-Capable SGA Systems The following list of clinically available SGA systems is not intended to be comprehensive, as most first-generation SGA masks based on the LMA design will support visualized intubation techniques with little or no modification to the mask itself (for example, cutting off the embedded 15-mm respiratory connector to permit the introduction of larger tracheal tube sizes in the LMA Classic or LMA Unique [both, Teleflex]). It has been estimated that globally, there are now more than 40 commercially available SGAs on the market.

AURA-I

AND

AURAGAIN

The Ambu Aura-i is a first-generation SGA that features an anatomically curved airway device with an integral rigid plastic bite block built into the ventilation tubing, which also serves to place the airway. The Aura-i is intended as a general-use SGA that features convenient depth markings for monitoring correct position, as well as navigation marks for guiding flexible endoscopes in the event that it is used as a tracheal intubation introducer with fiber-optic visualization. The mask supports the placement of standard endotracheal tubes with flexible fiber-optic endoscopes.

A study of 120 pediatric patients looked at the ease of insertion, time of insertion and number of attempts at flexible fiber-optic insertion through the mask, comparing the Aura-i and the air-Q (Cookgas; distributed

by Mercury Medical), and revealed no significant differences between these two SGA devices.8 The Aurai is manufactured in various sizes, from infant (sizes 1 and 1 ½) to pediatric (sizes 2 and 2 ½) to adult (sizes 3, 4, 5, and 6).

The Ambu AuraGain (Figure 3) is a second-generation SGA device, recently released in the US market, that is structurally similar to the Aura-i with respect to its shape, rigid bite-resistant airway insertion tubing and the contour of the mask; the AuraGain, however, has a dedicated gastric drainage channel. The mask

supports the placement of standard endotracheal tubes with flexible fiber-optic endoscopes. Published clinical studies are not yet available, but the airway shows much promise as a general-use airway as well as an SGA to support flexible fiber-optic intubation. A simulation study in cadavers9 assessed the effectiveness of AuraGain placement to facilitate intubation, and indicated that the mask performs well in its ability to seal and align with the upper esophageal sphincter.

I-GEL

The i-gel (Intersurgical) is a second-generation SGA that uses a radically different construction from LMAtype SGAs, in that it is constructed with a soft medical-grade thermoplastic elastomer with a noninflatable cuff and has an integral gastric drainage channel that extends to its tip (Figure 4).

The mask was designed to create a noninflatable anatomic seal of the pharyngeal, laryngeal and perilaryngeal structures while avoiding the trauma that potentially can be caused by inflatable cuffs. Numerous published studies10,11 detail the excellent alignment of the i-gel mask with the laryngeal inlet when visualized with a fiber-optic bronchoscope, and this SGA has been adopted by several international pre-hospital medical services, including the Sydney, Australia helicopter emergency medicine service, as a rescue ventilation and intubation airway (using the Ambu aScope—a portable video-driven endoscopy system).

The i-gel is available in a full range of pediatric and adult sizes, and is the only manufactured SGA that is also available for veterinary use (as the v-gel for cats and rabbits).

Figure 3. Ambu AuraGain.

Figure 4. i-gel.

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TOTALTRACK VLM

AIR-Q

BLOCKER

The Totaltrack VLM (Figure 5; Medcomflow) represents a fusion of video laryngoscope technology within an SGA platform in a manner similar to the historically important LMA CTrach (Teleflex), with the addition of a distal suction channel in the tip of the mask, which thus qualifies this device as a second-generation SGA. The Totaltrack VLM uses disposable components with a reusable video camera and monitor, and relies on a tracheal tube within a dedicated channel to provide a seal for ventilation through the SGA mask. As such, the Totaltrack VLM can support continuous ventilation during intubation attempts without the use of flexible fiber-optic endoscopy equipment.

The air-Q Blocker Disposable Laryngeal Airway (Figure 6; Cookgas, distributed by Mercury Medical) is a modification of the existing air-Q SGA, which permits the passage of a proprietary balloon-tipped suction catheter posterior to the mask in a simple guide channel positioned along the right side of the ventilation-insertion tubing. This balloon-tipped catheter has a spherical shape whose size can be appropriately adjusted for the patient with careful attention to the inflation balloon; each blocking catheter is sized appropriately for their respective airways. The air-Q Blocker is available in half sizes (2.5, 3.5, and 4.5), with the 4.5 intended for use on average-sized adult males, the 3.5 intended for use on average-sized adult females, and the 2.5 intended for use on small adult females or adolescent patients.

The air-Q mask itself is morphologically similar to the LMA Classic, but differs greatly with respect to the angle at which the ventilation tubing meets the mask and in the construction of the mask itself. The presence of a raised heel in later models allows the air-Q to achieve seal pressures similar to the LMA ProSeal (Teleflex), as this feature engages the base of the tongue in a way similar to that of the LMA ProSeal. The air-Q is available in a full range of neonatal, pediatric and adult sizes. Numerous studies in pediatrics and adults detail its utility as a conduit for tracheal intubation.12-15

Clinical Use: Description of 2 Intubation Methods Through the air-Q SGA and Removal Procedure

Figure 5. Totaltrack VLM.

Figure 6. air-Q Blocker Disposable Laryngeal Airway

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The following presentations are intended to familiarize medical professionals with the intubating capability of one specific brand of SGA. Should a clinician lack familiarity with endoscopic intubation techniques, I recommend that he or she receive specific, focused training from an expert colleague or at an appropriate airway management seminar. These techniques should be practiced first on airway intubating mannequins prior to clinical use. This information is presented solely for the purpose of medical education.

Patient safety is paramount, of course, so attention to oxygenation, ventilation, and airway decontamination (should emesis occur) is key. It is possible to perform these techniques with spontaneous ventilation under moderate to deep sedation if the clinician understands that the use of a topical local anesthetic will be necessary through the working channel of the endoscope. There are multiple drug regimens to produce moderate to deep sedation, the choice of which I leave to the judgment and experience of the clinician.

Three procedures will be discussed: • Intubation through an SGA with a flexible fiberoptic bronchoscope; • Intubation through an SGA with a video stylet; and • Removal of the SGA with the air-Q removal stylet.

PROCEDURE 1. INTUBATION THROUGH AN SGA WITH FLEXIBLE FIBER-OPTIC BRONCHOSCOPE

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Step 1: Prepare the air-Q SGA for tracheal intubation The patient is a 150-kg male and a 4.5 air-Q is used.

This procedure is demonstrated with the use of general anesthesia and non-depolarizing muscle blockade, although it can also be performed with spontaneous ventilation (volatile anesthesia technique or total IV anesthesia [TIVA]) or with moderate to deep sedation in those cases in which the clinical scenario makes this necessary. Topical local anesthesia is necessary, which can be provided through the suction channel/working channel of the bronchoscope (Figure 7).

First, begin with removal of the proprietary 15-mm connector to allow the insertion of a prelubricated standard tracheal tube to approximately 15-cm depth, so that the tracheal tube does not extend beyond the ventilation tubing and into the bowl of the SGA. Connect the tracheal tube to the ventilator breathing circuit utilizing an endoscopic port adapter to allow continuous oxygenation during the endoscopy and intubation.

Second, in order to permit continuous ventilation during endoscopy, a small amount of air can be added to the tracheal tube’s cuff to seal the interior of the SGA, with the understanding that this small amount of air must be removed prior to advancement of the tracheal tube over the bronchoscope and into the trachea.

Step 2: The initial endoscopy through the tracheal tube and SGA mask Insert (Figure 8) the flexible endoscope through the endoscopic port adapter and advance the endoscope past the tip of the tracheal tube into the bottom portion of the SGA mask. A wedge-shaped protrusion exists at the bottom of the ventilation tubing (designated as the “ramp” by the manufacturer of this SGA). In Ambu brand intubating airways, a small graphic is printed on the mask at this location, which is a visual cue to begin engaging the control lever of the bronchoscope into the flexion to look upward toward the larynx.

As the bottom of the ventilation tubing is reached, the endoscopist prepares to slowly and gently engage the control lever into flexion of the articulating distal tip of the endoscope.

Step 3: Flex the endoscopic control lever to visualize the larynx (Figure 9) Step 4: Advance the flexible endoscope into the larynx As the flexible endoscope is advanced into the larynx, the smooth portion of the interior of the thyroid cartilage is visualized. The endoscope tip is then extended through slow and careful manipulation of the control lever in order to align the tip of the endoscope with the posterior, caudal direction of the trachea (Figure 10).

As the control lever is extended, the bronchoscope is advanced down the trachea to the level of the carina or even the proximal right mainstem bronchus (Figure 11).

Step 5: Advance the endotracheal tube over the bronchoscope into the trachea Important tips to ensure smooth advancement of the

Figure 7.

Figure 8.

Figure 9.

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tracheal tube through the SGA and into the larynx and trachea (Figure 12) include: Turn the tracheal tube 90 degrees counterclockwise during advancement to minimize the gap between the tracheal tube and the endoscope at the level of the right corniculate cartilage (the most common site of tube hang-up). Should hang-up during advancement occur, withdraw and turn the tracheal tube leftward (counterclockwise) to disengage the point of hangup; otherwise, this problematic step of the intubation process will continue to thwart laryngeal and tracheal intubation.

Gentle traction on the ventilation tubing of the SGA itself will flatten the angle of attack with respect to tracheal tube advancement as well by compressing the base of the tongue in a manner akin to a laryngoscope blade. This maneuver will also serve to straighten the course of the tracheal tube from the exit point of the SGA, as it is common that most SGAs are placed too deeply during initial insertion, and this causes a very acute angle from the point of view of a flexible

endoscope exiting the SGA and passing through the larynx. It is important to withdraw the SGA slightly to reduce or eliminate this occurrence, as excessive force during this portion of the procedure will actually cause the bronchoscope to withdraw from the trachea and larynx and pass posteriorly into the esophagus.

If force is used during this phase of the intubation due to hang-up on the right corniculate cartilage or due to an acute angle between the bronchoscope and larynx, tracheal intubation will not be possible, and laryngeal trauma can occur.

PROCEDURE 2. INTUBATION THROUGH VIDEO STYLET

Figure 10.

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SGA WITH

A

Video stylet endoscopes are video-driven versions of optical stylets, which are devices that have been clinically available since the 1970s. This method of tracheal intubation through the SGA will be effective through an LMA Classic, LMA Unique, air-Q, and most clinical variants based on the LMA Classic design. Unfortunately, this technique will not function with SGAs that

Figure 12.

Figure 11.

AN

Figure 13.

have rigid bite block portions such as the Ambu Aura-i, AuraGain, and the i-gel, as these SGAs will not allow a rigid preformed stylet to transit the airway around the base of the tongue to the ventilation outlet.

This description uses the air-Q SGA (4.5 size) for convenience, as was the case in the previous procedure, as a larger tracheal tube was required to efficiently ventilate this patient (in this case, changed from 7.0 to 8.0).

This procedure is demonstrated with the use of general anesthesia and non-depolarizing muscle blockade, although it can be performed with spontaneous ventilation (with volatile anesthesia technique or TIVA) or with moderate to deep sedation in cases should that be necessary due to the clinical scenario. Topical local anesthesia can be instilled with a variety of techniques through the ventilation tubing of the SGA if this technique is performed under sedation. The endoscope used in this procedure is a video stylet produced by UE Medical Devices.

Step 1: Preparing the air-Q SGA for tracheal intubation Begin (Figure 13) with the removal of the proprietary 15-mm connector to allow the insertion of the prelubricated standard tracheal tube, which has been loaded onto the video stylet (lubricate the tracheal tube and video stylet prior to the procedure).

Using the natural curved shape of the video stylet, follow the curve of the SGA around the base of the tongue until the tip of the tracheal tube and stylet endoscope approaches the bottom portion of the SGA. Step 2: Identify the ventilation outlet at the bottom of the mask At the bottom of the air-Q SGA is a wedge-shaped protrusion (Figure 14). At the bottom of the mask, the rigid video stylet is now in position to lift and rotate through a cephalad arc that will bring the tip of the tracheal tube and stylet endoscope up and into alignment with the larynx.

Step 3: Lift and rotate cephalad the stylet through the SGA into the larynx This maneuver (Figure 15) has been called the “onearmed bandit,� as it resembles the pulling of the lever on a slot machine. Using the one-armed bandit maneuver will rotate the tip of the tracheal tube through the body of the SGA anteriorly in a natural motion that follows the contour of the airway up into the larynx. The motion mostly occurs in the elbow, and not the wrist.

This maneuver is also useful in tracheal tube delivery with hypercurved video laryngoscopes, such as the GlideScope (Verathon) and the C-MAC D-Blade (Karl Storz Endoscopy), when a rigid stylet is used, such as the GlideRite (Verathon) stylet.

Step 4: Rotate the tracheal tube and stylet into the larynx and identify the interior of the larynx (Figure 16) Step 5: Advance the tracheal tube off the stylet with a subtle caudad-posterior tilt to align the tip of the tracheal tube and video stylet with the long axis of the trachea As this technique (Figure 17) leads with the edge of the tracheal tube itself, it is much less prone to hanging

Figure 14.

Figure 15.

Figure 16.

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up on the larynx; however, due to the anterior arc of this intubation method, it must be stressed that after the tracheal tube enters the larynx, a problem in tube advancement may occur if the tip of the tracheal tube and stylet are not rotated forward to change the direction of the tracheal tube away from the anterior wall of the thyroid cartilage.

The video stylet is rotated out of the tracheal tube and SGA as the tracheal tube is advanced off the stylet. This is a very easy and smooth maneuver, especially if proper lubrication of the stylet and tracheal tube is accomplished before the procedure.

PROCEDURE 3. REMOVAL REMOVAL STYLET

Figure 17.

Figure 18.

OF AN

SGA WITH

THE AIR-Q

Step 1: Prepare the tracheal tube to receive the removal stylet by twisting it free from its connection with the tracheal tube (Figure 18).

Step 2: Firmly connect the air-Q removal stylet with the proximal tracheal tube with a 90- to 120-degree clockwise twist to permit the locking grooves/serrations to engage the plastic of the tracheal tube with a secure purchase (Figure 19).

Step 3: Begin to remove the air-Q SGA over the removal stylet-tracheal tube combination by maintaining constant positioning of the tracheal tube (with pressure exerted inward toward the trachea) and with gentle pressure on the SGA to ensure its removal (Figure 20).

Ensure that the endotracheal tube’s pilot balloon follows the tracheal tube through the ventilation tubing of the SGA. Step 4: Rotate the bowl of the SGA mask (posteriorly) to grasp the proximal portion of the tracheal tube and the locking portion of the removal stylet (Figure 21).

Ensure that the pilot balloon of the tracheal tube has followed through the ventilation tubing of the SGA. Finish removing the SGA. Step 5: Unlock the removal stylet connection with the proximal tracheal tube using a leftward or counterclockwise twist and replace the 15-mm connector on the tracheal tube (Figure 22).

Verify tracheal tube placement with capnography and with auscultation of breath sounds. Note the depth of tracheal tube placement on the centimeter markings.

Conclusion

Figure 19.

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Simplified algorithms for difficult airway management, such as the Vortex algorithm,16 suggest an expanded and early use of SGA devices for both ventilation and tracheal intubation. Although the use of SGAs for airway management in routine cases has begun to eclipse the use of tracheal intubation in elective surgery worldwide, knowledge and experience with techniques to employ them as tracheal tube introducers is still a relatively new topic in anesthesiology, and currently is a hot topic in the specialty of emergency medicine.

Continued research, simulation, and academic as well as clinical studies of these techniques are vital to the future of modern airway management preparedness.

Figure 20.

Figure 21.

Figure 22.

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References 1.

Wilson ME, Spiegelhalter D, Robertson JA, et al. Predicting difficult intubation. Br J Anaesth. 1988;61:211-216.

2. Butler PJ, Dhara SS. Prediction of difficult laryngoscopy: an assessment of the thyromental distance and Mallampati predictive tests.

Anaesth Intensive Care. 1992;20:139-142.

3. Savva D. Prediction of difficult tracheal intubation. Br J Anaesth.

1994;73:149-153.

4. Berkow LC, Schwartz JM, Kan K, et al. Use of the Laryngeal Mask Airway-Aintree Intubating Catheter-fiberoptic bronchoscope technique for difficult intubation. J Clin Anesth. 2011;23:534-539.

5. DuCanto J, Lungwitz Y, Koch A, et al. Mechanical ventilation and resuscitation under water: Exploring one of the last undiscovered environments–a pilot study. Resuscitation, 2015;93:40-45.

6. Stone BJ, Chantler PJ, Baskett PJ. The incidence of regurgitation during cardiopulmonary resuscitation: a comparison between the bag valve mask and laryngeal mask airway. Resuscitation.

1998;38:3-6.

7.

Halaseh B, Sukkar ZF, Hassan LH, et al. The use of ProSeal laryngeal mask airway in caesarean section—experience in 3000 cases.

Anaesth Intensive Care. 2010;38:1023-1028.

10. Darlong V, Biyani G, Baidya DK, et al. Air-Q blocker: a novel supraglottic airway device for patients with difficult airway and risk of aspiration. J Anaesthesiol Clin Pharmacol. 2014;30:589-590.

11. Jagannathan N, Roth AG, Sohn LE, et al. The new air-Q intubating laryngeal airway for tracheal intubation in children with anticipated difficult airway: a case series. Paediatr Anaesth.

2009;19:618-622.

12. Jagannathan N, Kho MF, Kozlowski RJ, et al. Retrospective audit of the air-Q intubating laryngeal airway as a conduit for tracheal intubation in pediatric patients with a difficult airway. Paediatr Anaesth. 2011;21:422-427.

13. Joffe AM, Liew EC, Galgon RE, et al. The second-generation air-Q intubating laryngeal mask for airway maintenance during anaesthesia in adults: a report of the first 70 uses. Anaesth Intensive Care. 2011;39:40-45.

14. Chrimes N, Fritz P. The vortex approach: management of the unanticipated difficult airway. Melbourne, Australia: eBook; 2013. http:// vortexapproach.com/Vortex_Approach/Vortex.html. Accessed July 10, 2015.

8. Jagannathan N, Sohn LE, Sawardekar A, et al. A randomized trial comparing the Ambu® Aura-i™ with the air-Q™ intubating laryngeal airway as conduits for tracheal intubation in children. Paediatr Anaesth. 2012;22:1197-1204.

15. Gatward JJ, Cook TM, Seller C, et al. Evaluation of the size 4 i-gel airway in one hundred nonÐparalysed patients. Anaesthesia.

2008;63:1124-1130.

9. Lopez AM, Sala-Blanch X, Valero R, et al. Cross-over assessment of the Ambu AuraGain, LMA Supreme New Cuff and Intersurgical I-Gel in fresh cadavers. Open J Anesth. 2014;4:332-339.

16. Akan B, Erdem D, Albayrak MD, et al. Pressure support ventilation with the I-gel in intensive care unit: case report. Braz J Anesth (English Edition). 2013.

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Securing Airways with a Gentle Touch TaperGuard™ Cuff Technology High-volume, low-pressure (HVLP) cuffs were introduced to help avoid tracheal racheal 1 damage. But do they go far enough? Compared to traditional HVLP LP cuffs, newer, taper-shaped cuffs can both enhance fit* across patients a d reduce pressure impact on the trachea.2 In other words, these new cuffs help you secure airways with a gentle touch.

Learn more at Covidien.com/TaperGuard5

* Compared with traditional HVLP cuffs, taper- shaped cuffs can accommodate more trachea sizes and shapes.

1. Seegobin RD, van Hasselt GL. Endotracheal cuff pressure and tracheal mucosal blood flow: endoscopic study of effects of four large volume cuffs. Br Med J (Clin Res Ed). 1984;288(6422):965–968.

2. Li Bassi G, Ranzani OT, Marti JD, et al.. An in vitro study to assess determinant features associated with fluid sealing in the design of endotracheal tube cuffs and exerted tracheal pressures. Crit Care Med. 2013;41: 518–526.

COVIDIEN, COVIDIEN with logo, Covidien logo and positive results for life are U.S. and internationally registered trademarks of Covidien AG. Other brands are trademarks of a Covidien company. ©2015 Covidien. 14-AW-0121

PRINTER-FRIENDLY VERSION AVAILABLE AT ANESTHESIOLOGYNEWS.COM

Use of Topical Anesthetics To Support Intubation Faculty Reviewers

CARLOS ARTIME, MD Assistant Professor Department of Anesthesiology The University of Texas Health Science Center at Houston Houston, Texas

KENNETH CANDIDO, MD Chairman Department of Anesthesiology Advocate Illinois Masonic Medical Center Chicago, Illinois

JULIE GOLEMBIEWSKI, PHARMD Clinical Associate Professor Clinical Pharmacist University of Illinois College of Medicine at Chicago Chicago, Illinois

TRICIA MEYER, PHARMD Associate Professor of Anesthesiology Texas A&M University College of Medicine Bryan, Texas The faculty reviewers reported no relevant financial disclosures. The medical writer, Lynne Peeples, also reported no relevant financial disclosures.

T

opical anesthetic products

can play a pivotal role in the comfort and safety of patients

in the operating room. When used in conjunction with awake intubation, for example, and delivered with skill and care, these agents can lessen or even eliminate the need for sedation, thereby greatly improving patient cooperation during surgical procedures.

By reversibly anesthetizing the nerve endings near the site of administration, topical anesthetics produce a transient and localized loss of sensation and, therefore, can decrease pain and discomfort during procedures in the operating room (OR). Topical anesthetics are generally only effective on intact mucosal surfaces, such as those inside the mouth, nose, eyes, throat, genitals, and other inner body surfaces.

Topicalization of the Airway Prior to a Procedure One of the most common uses of topical anesthetics in the OR is to prepare a patient for endoscopy, intubation, bronchoscopy, or a similar invasive airway procedure. Applying a topical anesthetic inside the throat before inserting a tube or scope can suppress the gag reflex, especially in an awake patient. For patients with a difficult airway, such as those with large glottic tumors or with an unstable cervical spine, securing the airway before induction of general anesthesia can minimize the risk for major airway-related complications, such as hypoxic brain damage and death.1

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The most common topical anesthetics for airway indications include atomized or nebulized spray preparations of lidocaine and benzocaine, alone or in combination with tetracaine. Preparations can differ in administration method, focus of application (oral or nasal route), speed of onset, length of action, and safety. Given the growing awareness of the increased risk for methemoglobinemia associated with use of some benzocaine formulations, clinicians may prefer lidocaine to obtain airway anesthesia.2

Formulations The first topical anesthetic, cocaine, was prepared for clinical use in the latter half of the 19th century.3 Today, clinicians have a choice of several relatively safe and effective anesthetic products, available as regular or viscous solutions, gels, ointments, and in spray cans. Lidocaine and benzocaine, alone or in various combinations with cocaine, prilocaine, tetracaine, and epinephrine are the formulations most commonly found in the OR (Table 1).

LIDOCAINE An amide anesthetic, lidocaine has a rapid onset of clinical activity of about 2 to 5 minutes and its effects typically last from 15 to 60 minutes or more.4 The drug is available in various concentrations, including 1%, 1.5%, 2%, and 4%, and can come with or without epinephrine. Combination formulations may be appropriate when vasoconstriction is desired, such as during nasal topicalization. Lidocaine’s liquid form can be nebulized or atomized, which can be ideal for spraying an anesthetic directly into the airway. Ointments and gels are also available. Up to 8 mg/kg of body weight is generally considered safe for application of lidocaine to the airway.

BENZOCAINE Benzocaine is an ester local anesthetic with a very fast onset of action within 1 minute.5 Compared with lidocaine, however, its duration of action is also shorter— between 5 and 15 minutes.6 The drug is available in various preparations and is administered via different devices.

HurriCaine (Beutlich) is comprised of benzocaine (20%).7 Again, onset is fast (<1 minute) and duration is generally around 15 minutes. HurriCaine One contains the same formula as HurriCaine, but comes unit-dosed as opposed to a 30-mL bottle.

Exposure to benzocaine may result in toxic effects, such as methemoglobinemia (see section on methemoglobinemia, page 53, for more information on this adverse reaction).

BENZOCAINE/BUTAMBEN/TETRACAINE Cetacaine (Cetalyte) is a prescription commercial spray that includes a mixture of benzocaine (14%), butamben (2%), and tetracaine (2%).8 The latter is another potent anesthetic of the ester class. In combination, the anesthetics provide relatively fast action (<1 minute) and moderate duration (30-60 minutes). The spray formulation should be applied for one second or less, not to exceed 2 seconds. It is available in spray, liquid, or gel forms.

Drug Administration In addition to direct application of gels, creams, and ointments, topical anesthetics are also commonly administered as a liquid via various delivery devices.

Atomization devices are designed to deliver topical anesthesia into nasal, oral, pharyngeal, laryngeal, and

Table 1. Common Topical Formulations Onset and Duration of Action

Chemical Name

Composition

Benzocaine (various; HurriCaine; HurriCaine One

Ester class anesthetic; various strengths; HurriCaine formulations at 20%

Onset: <1 min Duration: 5-15 min

• Commonly used for topicalizing the airway prior to a procedure • Reports of methemoglobinemia; HurriCaine One (unit-dosed) may decrease risk associated with longer sprays

Benzocaine/ Butamben/ Tetracaine (Cetacaine)

Prescription spray: benzocaine (14%), butamben (2%), tetracaine (2%)

Onset: <1 min Duration: 15-30 min

• Limit to <2 sec of spray • Reports of methemoglobinemia

Lidocaine

Amide class anesthetic Most common solutions: 1%, 1.5%, 2%, and 4%

Onset: 2-5 min Duration: 15-60 min

• Commonly used for topicalizing the airway prior to a procedure and anesthetizing skin prior to a cutaneous puncture • Formulations with added epinephrine can help achieve vasoconstriction • Adverse reactions more common in patients with heart disease • Reports of methemoglobinemia

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Clinical Considerations

tracheal tissues (Table 2). The devices deliver atomized droplets of the liquid anesthetic. Depending on the device, it can be difficult to gauge just how much of the anesthetic is being delivered into the patient.

Mucosal atomization devices, such as the LMA MADgic (Teleflex), produce a relatively tight stream of atomized droplets and include a syringe with volume markers, allowing for more precise dosing. Also of concern with atomization devices is the potential loss of some anesthetic into the atmosphere during administration.

Nebulizers tend to produce smaller droplets than atomization devices. Used with standard settings, these droplets are so fine that they often settle into the deepest part of the lungs rather than the upper airway. To create larger droplets that reach the upper airway, a nebulizerâ&#x20AC;&#x2122;s oxygen flow rate can be lowered.

A strategy used by clinicians is to begin anesthetizing a patient with a small amount of nebulized anesthetic, such as lidocaine, at low flow rates, to provide background numbing. Then they may transition to an atomization device to target sensitive areas, such as around the vocal cords and lower pharynx.

Some clinicians may also choose to apply a cotton pledget soaked in local anesthetic to targeted mucosal surfaces to achieve a selective blockade of underlying nerves. More direct nerve blocks in the airway can be achieved using needle-based techniques. Some clinicians advocate using such blocks in conjunction with topical anesthetics; others prefer using topicals exclusively. If needle blocks are used, it is important to note that the technique may be contraindicated in certain patients, such as those with coagulopathies and/ or who are being treated with anticoagulants.9 Additionally, the blocks can cause complications, including bleeding, nerve injury, and seizures from intravascular injection.4 For more details on the use of needle-based airway blocks, see the review by the New York School of Regional Anesthesia.10 Additional airway strategies can help maximize the effectiveness of topical anesthetics. For nasal intubation, adding vasoconstrictors such as epinephrine at a concentration of 1:200,000, or phenylephrine at a concentration of 0.05%, to the local anesthetic can prolong the topical anesthetic effect and help reduce mucosal bleeding. Also, the administration of glycopyrrolate can help reduce the production of saliva, which acts as a barrier between the anesthetic agent and the mucosa.

Safety Considerations ALLERGIC REACTIONS It is rare for a patient to be allergic to a topical anesthetic, especially those of the amide class such as lidocaine. Actual hypersensitivity reactions account for less than 1% of all reactions to local anesthetics.11,12 The amount of drug administered and the route of administration can influence the side effects of topical anesthetic agents. Care should be taken with topical anesthetics to ensure that the predetermined amount

of the drug is administered to produce the intended effect while also minimizing the risk for toxicity.

An allergic reaction to certain topical anesthetics, more often those of the ester than the amide class, may manifest on the skin as mild redness and burning to discoloration and swelling. More serious side effects, such as tissue necrosis and sloughing of the skin, have also been reported.13

CENTRAL NERVOUS SYSTEM EFFECTS High plasma concentrations of anesthetics can stimulate the central nervous system (CNS), potentially causing seizures. This can be followed by CNS depression, including respiratory arrest. Solutions that contain epinephrine may add to the CNS stimulatory effect, which may be confused with a bona fide allergic type of reaction.14-16 Life-threatening adverse effects have been known to occur following topical anesthetic application over large areas of the body, especially when plastic occlusives are applied to enhance absorption.17 The FDA issued an advisory on the potentially life-threatening side effects of topical anesthetics after 2 women experienced seizures, coma, and death after applying topical anesthetics to their legs with an occlusive dressing before laser hair removal.17 Caution is also warranted when applying local anesthetics to mucosal areas.

CARDIOVASCULAR EFFECTS High plasma levels of anesthetics may depress heart function and result in bradycardia, arrhythmias, hypotension, cardiovascular collapse, and cardiac arrest.18 Anesthetics that contain epinephrine can trigger hypertension, tachycardia, and angina.

METHEMOGLOBINEMIA Methemoglobinemia occurs when iron in hemoglobin is transformed from ferrous to ferric form, or methemoglobin. Unlike hemoglobin, methemoglobin is unable to transport oxygen to body tissues. The resulting oxygen deprivation can affect the CNS and cardiovascular system, manifesting as lightheadedness, confusion, hypoxia, and cyanosis.19 Acquired methemoglobinemia can be life-threatening, but early recognition and treatment will greatly improve outcomes in this reversible condition. Methemoglobinemia can be identified via symptoms or the use of a pulse CO oximeter, such as the Rad-57 (Masimo).20 With significant methemoglobinemia, the oxygen saturation will trend toward 85% on standard pulse oximetry. An IV dose of 1 to 2 mg/ kg of methylene blue is usually enough to reverse methemoglobinemia.21 Transfusion or dialysis is preferred for patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency because methylene blue can trigger hemolytic anemia.

Prevention of methemoglobinemia is preferable, of course. Using multiple sprays of an agent or spraying the area for a longer duration than recommended is often the culprit in cases of methemoglobinemia. Unclear package instructions, or application by clinicians

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unfamiliar with the significant absorption of topical anesthetics, may lead to overdoses. For some patients, however, even tiny amounts—well within recommended dosing—can result in clinically significant methemoglobinemia. Numerous case reports have been reported involving as little as 1 second of spraying of Cetacaine or delivery of 15 to 25 mg/kg of benzocaine.22,23 Up to 1 in every 370 patients will be particularly susceptible to developing methemoglobinemia, likely due to genetic variation.24 Infants under age 6 months, older patients, and individuals with respiratory or cardiac

disease may also be sensitive to low methemoglobin levels.23 Clinical situations such as anemia or hypoalbuminemia can raise the risk.25 A Johns Hopkins study found 138 patients with raised methemoglobin levels during a 28-month period.26 If the area being sprayed is inflamed or the skin is broken, a larger volume of the drug may be absorbed than was intended. Concomitant use of other drugs, such as isosorbide dinitrate, can also increase the likelihood of methemoglobinemia.25 The anesthetic most commonly associated with the condition is benzocaine. Reports received by the FDA

Table 2. Atomization Devices 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 that 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 (Teleflex)

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 MADgic Airway Intubating Airway with Mucosal Atomization and Oxygen Delivery (Teleflex)

For difficult and awake airways requiring a fiber-optic scope, the device combines atomized topical anesthetic and oxygen delivery in an innovative and elegantly designed fiber-optic–compatible oral airway.

Typical particle size 30-100 microns. System dead space 0.15 mL. Oxygen flow rate 2-3 L/min at 50 psi. Size 9 cm airway (6.5-8.0 ET).

LMA MADgicWand Mucosal Atomization Device (Teleflex)

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

Typical particle size: 30-100 microns. System dead space: 0.25 mL.

LMA MADgic LaryngoTracheal Atomizer (Teleflex)

Mucosal atomization device that incorporates a small flexible, malleable tube with an internal stiffening stylet that connects to 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 (Teleflex)

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).

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between November 1997 and March 2002 described 132 cases of benzocaine-induced methemoglobinemia. Most of the cases (93.2%) involved benzocaine spray. Furthermore, of the 69 cases that specified a dose, 37 (53.6%) indicated that only a single spray was applied.27 The total number of benzocaine-induced cases of methemoglobinemia in the literature is in the hundreds, and this likely represents an underestimation of the actual number of cases.28 Because of the greater risk for methemoglobinemia, Veterans Administration (VA) hospitals have banned benzocaine in favor of

lidocaine.29 A VA report describing 35 reported cases of methemoglobinemia, however, did link more of those cases (6 or 17%) to the use of lidocaine than to Cetacaine (4 or 11%).28 The majority of the cases were attributed to generic benzocaine (24 or 69%). It has been theorized that the lower rate of methemoglobinemia seen with Cetacaine may be due to the prescription product being designed to deliver a more precise quantity of benzocaine and at a lower concentration than is the case with generic formulations. However, published evidence for that is lacking.

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 for use by those trained and experienced in techniques of flexible fiberoptic intubation.

An accessory to a bronchoscope. Delivery form: 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 atomizing nozzle, creating liquid spray. Gas flow adjusted to 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 toylike presentation make 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).

For use with fiber-optic bronchoscopy.

Intubating airway with mucosal atomization and oxygen delivery.

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 patientâ&#x20AC;&#x2122;s anatomy. Delivery of a fine spray mist generated by a piston syringe. Luer connection adapts to any luer lock syringe.

Nonsterile. Single use.

Intranasal medication delivery offers rapid, effective method to deliver selected medications to patient without need for a painful shot and without delays in onset seen with oral medications.

Rapidly effective (atomized nasal medications absorb directly into bloodstream, avoiding first-pass metabolism; atomized nasal medications absorb directly into the brain and cerebrospinal fluid via olfactory mucosa to noseâ&#x20AC;&#x201C;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).

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Clinicians can follow several strategies to reduce the risk for methemoglobinemia, including accurately documenting the amount of drug administered (Table 3).

The Pharmacist’s Role Pharmacists can play a significant role in ensuring topical anesthetic products are chosen, dated, stored, and administered appropriately. A pharmacist might, for example, look at the safety and efficacy of various

products, alongside a cost table, to make the most costeffective choice for his or her institution. The pharmacist can also label and store preparations for topical use in a way so that they are not unintentionally administered incorrectly. By posting maximum doses and educating staff on the signs and symptoms of methemoglobinemia and systemic absorption, as well as on how to prevent and treat the condition, a pharmacist can help to prevent further cases at his or her institution.

References 1.

Hagberg C. Current concepts in the management of the difficult airway. Anesthesiology News. 2015;41(5). anesthesiologynews.com/ ViewArticle.aspx?d=Educational+Reviews&d_id=161&i=May+2015&i_ id=1183&a_id=32361. Accessed July 21, 2015.

2. Vailurupalli S, Manchanda S. Risk of acquired methemoglobinemia with different topical anesthetics during endocscopic procedures.

Local Reg Anesth. 2011;4:25-28.

3. Doyle D. Topical and Regional Anesthesia For Tracheal Intubation.

Anesthesiology News Guide To Airway Management. 2014. http:// anesthesiologynews.com/download/Topicals_ANGAM14_WM.pdf.

Accessed July 21, 2015.

4. www.drugs.com/mtm/lidocaine-topical.html. Accessed July 21, 2015.

5. Ruetsch YA, Boni T, et al. From cocaine to ropivacaine: the history of local anesthetic drugs. Curr Top Med Chem. 2001;1(3):175-182.

6. Hagberg C. Benumof and Hagberg’s Airway Management. 3rd ed.

Philadelphia, PA: Saunders Elsevier; 2013.

7.

beutlich.com/product-sheets. Accessed July 21, 2015.

8. www.cetacaine.com/dental/about/prescribing-information.

Accessed July 21, 2015.

9. Jeng CL, Torrillo TM, Rosenblatt MA. Complications of peripheral nerve blocks. Br J Anaesth. 2010;105 Suppl 1:i97-i107.

10. Regional & topical anesthesia for endotracheal intubation. New York School of Regional Anesthesia. www.nysora.com/techniques/nerve-stimulator-and-surface-based-ra-techniques/ head-and-neck-blocka/3022-regional-topical-anesthesia-forendotracheal-intubation.html. August 2013. Accessed July 20, 2015.

(Note that dexmedetomidine dose in the article is incorrect. It

should be loading dose: 1 mcg/kg over 10 min, infusion rate: 0.2-0.7 mcg/kg per hour.)

11. McEvoy GK, Miller J. Antipruritics and local anesthetics. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, Inc; 2007.

12. Wolters Kluwer Health, Inc. Local anesthetics, topical. Drug Facts & Comparisons. eFacts [online]. 2007.

13. Zempsky WT, Karasic RB. EMLA versus TAC for topical anesthesia of extremity wounds in children. Ann Emerg Med. 1997;30(2):163-166.

14. Daya MR, Burton BT, et al. Recurrent seizures following mucosal application of TAC. Ann Emerg Med. 1988;17(6):646-648.

15. Mercado P, Weinberg GL. Local anesthetic systemic toxicity: prevention and treatment. Anesthesiol Clin. 2011;29(2):233-243.

16. Becker DE, Reed KL. Essentials of local anesthetic pharmacology.

Anesth Prog. 2006;53(3):98-108.

17. US Food and Drug Administration. Public health advisory: lifethreatening side effects with the use of skin products containing numbing ingredients for cosmetic procedures. www.fda.gov/Drugs/ DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm054718.htm. February 6, 2007. Accessed July 5, 2015.

18. Lin F, Chang W, et al. Cardiovascular complications resulting from topical lidocaine application. Int J Gerontol. 2008;2(4):229-232.

19. Wilburn-Goo D, Lloyd L. When patients become cyanotic: acquired methemoglobinemia. JADA. 1999;130:826- 831.

20. Barker SJ, Curry J, Redford D, et al. Measurement of carboxyhemoglobin and methemoglobin by pulse oximetry: a human volunteer study. Anesthesiology. 2006;105(5):892.

21. Sikka P, Bindra VK, Kapoor S, et al. Blue cures blue but be cautious.

J Pharm Bioallied Sci. 2011;3(4):543-545.

Table 3. Minimizing the Risk for Methemoglobinemia Apply labels to topical anesthetic spray bottles to warn staff of dangers of excessive use in patients.

Ask questions when taking a patient’s medical history to identify risk factors.

Document the amount of drug being administered, including measuring and recording the number and duration of sprays applied.

(A reference chart listing maximum doses for topical anesthetics can be helpful.)

Keep supplemental oxygen and methylene blue on hand wherever topical anesthetics are used in patients.

Opt for delivery devices that provide more precision in drug administration.

Stock only 1 topical anesthetic product to reduce confusion with regard to dosing. Lidocaine may be a safer choice than benzocaine.

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22. Ellids FD, Seiler JG, Palmore MM. Methemoglobinemia: a complication after fiberoptic orotracheal intubation with benzocaine spray. A case report. J Bone Joint Surg Am. 1995;77-A(6):937-939.

23. Khorasani A, Candido KD, Ghaleb AH, et al. Canister tip orientation and residual volume have significant impact on the dose of benzocaine delivered by hurricaine spray. Anesth Analg. 2001;92:379-383.

24. Novaro GM, Aronow HD, et al. Benzocaine-induced methemoglobinemia: experience from a high-volume transesophageal echocardiography laboratory. J Am Soc Echocardiogr.

2003;16:170-175.

25. Vallurupalli S. Methemoglobinemia due to topical pharyngeal anesthesia during endoscopic procedures. Local Reg Anesth.

2010;3:137-142.

26. Ash-Bernal R, Wise R, Wright SM. Acquired methemoglobinemia: a retrospective series of 138 cases at 2 teaching hospitals. Medicine (Baltimore). 2004;83:265-273.

27. Moore TJ, Walsh CS, Cohen MR. Reported adverse event cases of methemoglobinemia associated with benzocaine products. Arch Intern Med. 2004;164(11):1192-1196.

28. US Department of Veterans Affairs. A guidance on the use of topical anesthetics for naso/oropharyngeal and laryngotracheal procedures. www.pbm.va.gov/PBM/clinicalguidance/criteriaforuse/benzocaine. pdf. February 2006. Accessed July 5, 2015.

29. Rodriguez LF, Smolik LM, Zbehlik AJ. Benzocaine-induced methemoglobinemia: report of a severe reaction and review of the literature. Ann Pharmacother. 1994;28(5):643-649.

Proven more effective than Benzocaine alone1

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Delivers a 30–60 minute duration

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Only genuine Cetacaine is indicated to control pain and reduce the gag reflex. With a unique combination of ingredients Cetacaine (Benzocaine 14%, Butamben 2.0%, Tetracaine Hydrochloride 2.0%), is also proven more effective than Benzocaine alone. That’s why so many hospitals request the little yellow bottle by name.

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TOPICAL ANESTHETIC SPRAY TOP

(Benzocaine 14.0%, Butamben 2.0%, Tetracaine Hydrochloride 2.0%) (Benz ni J, Mehta D, Naraghi M. Mixtures of local anesthetics: The Efectiveness of Combinations of 1 Adrian Benzo ocaine, Butamben, and Tetracaine Topically. Anesthesiology Review. 1981; 12:15-19. omplete safety information, prescribing information, warnings and contraindications, * For co see th he prescribing insert on the next page.

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Cetacaine

TOPICAL ANESTHETIC SPRAY Brief Summary of the Prescribing Information Active Ingredients Benzocaine ......................................................................14.0% Butamben..........................................................................2.0% Tetracaine Hydrochloride ..................................................2.0% Contains Benzalkonium Chloride .....................................................0.5% Cetyl Dimethyl Ethyl Ammonium Bromide .....................................................0.005% In a bland water-soluble base.

Action The onset of Cetacaine-produced anesthesia is rapid (approximately 30 seconds) and the duration of anesthesia is typically 30-60 minutes, when used as directed.

Indications Cetacaine is a topical anesthetic indicated for the production of anesthesia of all accessible mucous membrane except the eyes.

Cetacaine is indicated to control pain and for use for surgical or endoscopic or other procedures in the ear, nose, mouth, pharynx, larynx, trachea, bronchi, and esophagus.

Dosage and Administration Cetacaine Spray should be applied for approximately one second or less for normal anesthesia. Only a limited quantity of Cetacaine is required for anesthesia. Spray in excess of two seconds is contraindicted. Average expulsion rate of residue from spray, at normal temperatures, is 200 mg per second.

Adverse Reactions Hypersensitivity Reactions: Unpredictable adverse reactions (i.e. hypersensitivity, including anaphylaxis) are extremely rare. Localized allergic reactions may occur after prolonged or repeated use of any aminobenzoate anesthetic. The most common adverse reaction caused by local anesthetics is contact dermatitis characterized by erythema and pruritus that may progress to vesiculation and oozing. This occurs most commonly in patients following prolonged self-medication, which is contraindicated. If rash, urticaria, edema, or other manifestations of allergy develop during use, the drug should be discontinued. To minimize the possibility of a serious allergic reaction, Cetacaine preparations should not be applied for prolonged periods except under continual supervision. Dehydration of the epithelium or an escharotic effect may also result from prolonged contact.

Precaution: On rare occasions, methemoglobinemia has been reported in connection with the use of benzocaine-containing products. Care should be used not to exceed the maximum recommended dosage (see Dosage and Administration). If a patient becomes cyanotic, treat appropriately to counteract (such as with methylene blue, if medically indicated).

Use in Pregnancy: Safe use of Cetacaine has not been established with respect to possible adverse effects upon fetal development. Therefore, Cetacaine should not be used during early pregnancy, unless in the judgement of a physician, the potential benefits outweigh the unknown hazards. Routine precaution for the use of any topical anesthetic should be observed when Cetacaine is used.

Contraindications Cetacaine is not suitable and should never be used for injection.

Do not use on the eyes. To avoid excessive systemic absorption, Cetacaine should not be applied to large areas of denuded or inflamed tissue. Cetacaine should not be administered to patients who are hypersensitive to any of its ingredients or to patients known to have cholinesterase deficiencies. Tolerance may vary with the status of the patient. Cetacaine should not be used under dentures or cotton rolls, as retention of the active ingredients under a denture or cotton roll could possibly cause an escharotic effect. Routine precaution for the use of any topical anesthetic should be observed when using Cetacaine.

An appropriate pediatric dosage has not been established for Cetacaine Spray.

Rx Only. Made in U.S.A.

Dosages should be reduced in the debilitated elderly, acutely ill, and very young patients.

© 2014 Cetylite Industries, Inc. All rights reserved. Information is summary in nature and subject to change. Cetacaine and Cetylite are registered trademarks of Cetylite Industries, Inc. All other copyrights are the property of their respective owners.

Tissue need not be dried prior to application of Cetacaine. Cetacaine should be applied directly to the site where pain control is required.

Anesthesia is produced within one minute with an approximate duration of thirty minutes. Each 200 mg dose of Cetacaine Spray residue contains 28 mg of benzocaine, 4 mg of butamben and 4 mg of tetracaine HCl.

REV 4/2013

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Successful Tracheal Intubation In Children With Difficult Airways: Seven Secret Techniques Every Anesthesiologist Should Know JOHN E. FIADJOE, MD Assistant Professor of Anesthesiology and Critical Care Hospital of the University of Pennsylvania The Childrenâ&#x20AC;&#x2122;s Hospital of Philadelphia Philadelphia, Pennsylvania

MADHANKUMAR SATHYAMOORTHY, MBBS, MS Assistant Professor Department of Anesthesiology University of Mississippi Medical Center Jackson, Mississippi

VIKRAM PATEL, MD Assistant Professor of Clinical Anesthesiology Division of Pediatric Anesthesiology Vanderbilt University Medical Center Nashville, Tennessee The authors reported no relevant financial disclosures.

D

ifficult tracheal intubation (TI) in children

presents unique challenges for anesthesiologists.

These children have limited pulmonary reserve

and are prone to laryngospasm and airway activation.

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Secret #1 The Modified Nasopharyngeal Airway The modified nasopharyngeal airway (MNA) is simply an airway with a 15-mm adapter inserted into the flared end (Figure 1). It is easily put together in the operating room but is also commercially available. The appropriate length of the MNA should extend from the lateral nostril to the tragus of the ear.

Figure 1. Modified nasopharyngeal airway.

Figure 2. The air-Q accommodates cuffed pediatric tubes.

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Administering oxygen and inhaled anesthetic through the MNA is a useful technique to minimize hypoxemia and maintain anesthetic depth. After induction of anesthesia, a 5-second jaw thrust is a good way to assess anesthetic depth. A lack of response (ie, movement, tachycardia, tachypnea, or cough) indicates that conditions are optimal for airway manipulation. The MNA is inserted after applying oxymetazoline into the nose.

The adapter at the end of the MNA is connected to the anesthesia circuit, allowing the patient to receive inhaled anesthetic and oxygen throughout the intubation. The MNA is particularly advantageous for fiberoptic intubation through the contralateral nostril.3 The tip of an appropriately sized nasopharyngeal airway often sits directly above the glottic opening. If the MNA is visualized during fiber-optic intubation, it can be followed as a guide to the glottis, even when soft tissue obstruction occurs.

Secret #2 Continuous Ventilation Through The Supraglottic Airway The supraglottic airway (SGA) is an indispensible

Figure 3. The 15-mm tracheal tube adapter should be reinserted loosely.

Figure 4. View of the tracheal tube with a perforated swivel adapter.

All images courtesy of John E. Fiadjoe, MD

Small children are uncooperative with awake intubation and so usually require deep sedation or general anesthesia. Given this background, a thorough knowledge of pediatric airway management techniques is critical in order to minimize complications and encourage successful TI outcomes.

This article highlights â&#x20AC;&#x153;secretâ&#x20AC;? techniques for firstpass success with TI. These techniques are not secrets in the traditional sense of the word, however, but many of these techniques are not ubiquitously practiced and may help achieve first-pass TI in an efficient and safe way. First-pass TI is important because multiple intubation attempts have been associated with complications in adult tracheal intubations, pediatric intubations in the ICU, and in children with difficult TI.1,2

adjunct in airway management. It is often an effective rescue ventilation technique when face mask ventilation is difficult. Learning to intubate the trachea through an SGA is a basic skill for all anesthesiologists; it requires several discrete steps and can be complicated by the inability to fit the pilot balloon cuff of the selected tracheal tube into the SGA or dislodged tracheal tube when the SGA is removed.

Adding continuous oxygenation or ventilation during SGA intubation provides the operator with more time to secure the airway and manage any technical difficulties that may occur. The laryngoscopist should confirm that the selected tracheal tube and its pilot balloon pass completely through the SGA. The air-Q (Mercury Medical) SGA accommodates cuffed pediatric tubes with little resistance (Figure 2).

The 15-mm tracheal tube adapter should be removed and then reinserted loosely (Figure 3) so it can be readily removed when the SGA is withdrawn out of the pharynx. The tracheal tube is then inserted into the airway tube of the SGA, and the tracheal tube cuff is inflated to create a tight seal. Liberal lubrication of the airway tube of the SGA and outer aspect of the tracheal tube is helpful in passing the tracheal tube through the SGA. A perforated swivel adapter is placed on the end of the tracheal tube (Figure 4).

The SGA, tracheal tube, and swivel adapter unit is inserted after the child is anesthetized and connected to the anesthesia circuit. This technique allows the delivery of oxygen and inhaled agent during fiberoptic intubation through the swivel adapter. The fiberoptic bronchoscope is passed through the swivel adapter and in situ tracheal tube into the trachea.

Once the fiber-optic bronchoscope is placed in the trachea, the tracheal tube cuff is then deflated and the tube advanced gently into the trachea. Tracheal location is confirmed while the fiber-optic bronchoscope is being withdrawn from the SGA. After confirming successful TI, removing the SGA while maintaining the tube in the trachea is a delicate step. The ideal approach is to use laryngeal/long alligator forceps or

Figure 5. Removing the SGA while keeping the tube in the trachea is a delicate procedure.

a commercially available tube stabilizer to maintain the tracheal tube position while removing the SGA (Figures 5 and 6).

A second tube loaded on the bronchoscope can be used as a stabilizer during removal of the SGA. The SGA can be left in situ in precarious clinical situations.

Secret #3 How To Deal With the Tracheal Tube Pilot Balloon Cuff That Will Not Fit Through the SGA In many smaller-sized SGAs, the pilot balloon cuff of cuffed tracheal tubes may not pass through the SGA airway tube. If this occurs, the pilot balloon can be cut to allow intubation through the SGA (Figure 7). It can then be reconstructed post-intubation by inserting an angiocatheter into the cut end and applying a oneway valve on the end of the angiocatheter (Figure 8).

This allows for both the reinflation of the cuff and measurement of the cuff pressure. An epidural clamp connector applied to the cut end of the inflation line is equally as effective as the angiocatheter technique (Figure 9).4

Figure 6. Long forceps can help maintain the tracheal tube position when removing the SGA.

Figure 7. A pilot balloon can be cut to allow intubation through a small SGA.

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Secret #4 How To Deal With a Hung Tracheal Tube During Fiber-Optic Intubation Hang-up of the tracheal tube during fiber-optic intubation is a common problem during pediatric intubations. It is more likely when there is a large discrepancy between the tube size and the fiber-optic scope size (Figure 10). Every anesthesiologist should develop a series of routine steps to address this problem. There are at least 5 common steps that may help.

2. EXTERNAL

Manipulating the glottis externally can allow the tube to pass into the trachea if hang-up occurs. Routinely palpating the larynx during tracheal tube placement provides tactile feedback as to whether the tube hangs up or enters the trachea, and this maneuver also provides a solution (laryngeal manipulation) when hang-up does occur. This is one of the most effective methods for addressing a hung tube during advancement over a fiber-optic bronchoscope.

3. DIRECT 1. ROTATE

THE TUBE

A tracheal tube loaded on a bronchoscope has a natural position usually with the Murphy eye to the right of the operator when standing at the head of the bed (Figure 11). This may cause the tracheal tube to hangup on the patientâ&#x20AC;&#x2122;s right arytenoid when advanced. If this occurs, the tube should be withdrawn and rotated 90 degrees counterclockwise to reduce the chance of hang-up. Routinely advancing the tube with the bevel facing posteriorly will reduce the incidence of hang-up (Figure 12).

LARYNGEAL MANIPULATION

LARYNGOSCOPY OR VIDEO LARYNGOSCOPY

Direct laryngoscopy or video laryngoscopy (VL) performed during advancement of the tracheal tube off the fiber-optic bronchoscope may reduce hang-up by reducing soft tissue obstruction.

4. FIBER-OPTIC

BRONCHOSCOPE WITHDRAWAL

A key limitation of fiber-optic intubation is that passage of the breathing tube is blind. A technique unique to pediatric intubations with small tubes is the ability to withdraw the scope into the distal end of the tracheal tube in order to manipulate the tip of the tracheal tube around the cause of obstruction. The bronchoscope is withdrawn until it sits just inside the breathing tube.

Manipulation of the bronchoscope directs the tube and allows the operator to visualize and circumnavigate the cause of the obstruction.

5. PARKER

TUBE

The Parker tube (Parker Hannifin) has a curved tip that hugs the fiber-optic bronchoscope more effectively than standard tracheal tubes and readily slides into the trachea. If a large discrepancy exists between the scope size and tracheal tube size, using the Parker tube may reduce the chance of hang-up.

Figure 8. Post-intubation the pilot balloon can be reconstructed using an angiocatheter.

Figure 9. Another approach uses an epidural clamp connector.

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Secret #5 Combine Video Laryngoscopy With Fiber-Optic Bronchoscopy Video laryngoscopy is becoming routine in airway management. Although glottic exposure is usually adequate with VL, placement of the tracheal tube may remain challenging. Fiber-optic intubation requires good kinesthetic skill to manipulate the scope into the trachea. Combining VL with fiber-optic bronchoscopy may facilitate placement of the bronchoscope into the trachea, since the relative location of the bronchoscope to the glottic opening is visualized with VL, while the view from the distal tip is seen through the bronchoscope. Placing the fiber-optic bronchoscope into the trachea and then advancing the tracheal tube under visualization with the VL converts the blind insertion of the tracheal tube to a visualized technique. In this way, hang-up of the tube is immediately recognized and appropriate corrective maneuvers can be performed under continuous visual guidance.

Secret #6 Use Apneic Oxygenation Techniques Apneic oxygenation has been shown to delay desaturation in adults and older children. Apneic oxygenation can be achieved with a standard laryngoscope or VL with an integrated oxygen delivery side port or through a MNA, as described earlier. The airway should be kept open in order for effective bulk flow of oxygen to occur.

One study showed that after adequate preoxygenation, apneic oxygenation could maintain adequate saturation in children for 10 minutes and in infants for 2 minutes.5 Another report describes using a nasal cannula with 6 to 8 L/min oxygen flow in infants with pyloric stenosis to delay desaturation during rapid sequence intubation.6 Although these techniques are advantageous in apneic children, they are likely more efficacious in spontaneously ventilating patients. Advantages of spontaneous ventilation in difficult pediatric TI include better airway tone and less obstruction, delayed hypoxemia, and easier fiber-optic intubation. Fiber-optic intubation may be easier because spontaneously ventilating children often have visible bubbles in their airway from exhaled gases. When the visualized anatomy is poor, following these bubbles leads the bronchoscopist directly to the glottic opening.

Aristotle is noted to have said, “Excellence is an art won by training and habituation. We do not act rightly because we have virtue or excellence, but we rather have those because we have acted rightly. We are what we repeatedly do. Excellence, then, is not an act, but a habit.”

Figure 10. A large size discrepancy between the tube and fiber-optic scope can lead to a hang-up.

Secret #7 How To Rescue a Failed Nasal VL Intubation With a Nasogastric Tube Nasal intubation with VL can be challenging because, although the glottis is readily visualized, it may be difficult to direct the breathing tube into the glottis with Magill forceps. There is also a risk for rupturing the tracheal tube cuff if it is handled with Magill forceps. Even when the tube is successfully placed between the vocal cords, it may still hang up on the anterior tracheal wall and fail to pass into the mid-trachea.

A simple technique in support of nasal intubation is to place a small lubricated nasogastric tube through the tracheal tube, which is then inserted through the patient’s nose into the posterior pharynx. The nasogastric tube serves as a guide for the breathing tube through the nose and can be carefully inserted into the trachea using the forceps. The tube is then advanced over the nasogastric tube into the trachea. Although the tip of the nasogastric tube is blunt, it should not be inserted distally into the lung to avoid potential airway injury.

Figure 11. Hang-up is possible when the tube’s Murphy eye is situated to the right.

Conclusion Difficult intubation remains a cause of significant morbidity and mortality in children. The above techniques can facilitate airway management in children.

These skills can only be mastered with deliberate practice in patients with normal airways.

Figure 12. Withdrawing the tracheal tube and rotating 90 degrees counterclockwise will reduce risk for hang-up.

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References 1.

Graciano AL, Tamburro R, Thompson AE, et al. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: a report from National Emergency Airway Registry for Children: NEAR4KIDS. Intensive Care Med. 2014;40(11):1659-1669.

2. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg.

2004;99(2):607-613.

3. Holm-Knudsen R, Eriksen K, Rasmussen LS. Using a nasopharyngeal airway during fiberoptic intubation in small children with a difficult airway. Paediatr Anaesth. 2005;15(10):839-845.

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4. Kovatsis PG, Fiadjoe JE, Stricker PA. Simple, reliable replacement of pilot balloons for a variety of clinical situations. Paediatr Anaesth. 2010;20(6):490-494.

5. Cook TM, Wolf AR, Henderson AJ. Changes in blood-gas tensions during apnoeic oxygenation in paediatric patients. Br J Anaesth.

1998;81(3):338-342.

6. Bhagwan SD. Levitanâ&#x20AC;&#x2122;s no desat with nasal cannula for infants with pyloric stenosis requiring intubation. Paediatr Anaesth.

2013;23(3):297-298.

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Managing the Difficult Airway: Nine Challenging Cases

R

eaders of AnesthesiologyNews.com were asked to submit interesting and/or challenging airway management cases.

The following 9 cases were selected for publication.

Case 1: Submental Tracheal Intubation for a Patient With Multiple Facial Fractures

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Case 2: Managing the Unanticipated Difficult Intubation Due to Epiglottic Cyst

72

Case 3: Lasing Endobronchial Tumors Through a Supraglottic Airway

74

Case 4: Difficult Airway in Patients With Head or Neck Masses

76

Case 5: Challenges of Exchanging a Laryngeal Tube for an Endotracheal Tube

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Case 6: Direct Fiber-Optic Endotracheal Intubation for a Deformed Airway

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Case 7: Importance of Oropharyngeal Hygiene for Nonintubated Patients in the ICU

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Case 8: Use of Channeled-Blade Video Laryngoscope as Rescue Following Failed Inubation

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Case 9: Unpredictable Difficult Airway Due to Fibrotic Subglottic Bridge

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Submental Tracheal Intubation For a Patient With Multiple Facial Fractures CARLOS R. DEGRANDI OLIVEIRA, MD, TSA Santa Casa de Miseric贸rdia de Santos Santos, Brazil The author reported no relevant financial disclosures.

In the airway management of patients with multiple facial fractures, the tracheal tube in the oral cavity can interfere with the surgical procedure. It is therefore necessary for an alternative path to be used. When the patient does not require a long period of ventilation, one alternative is a submental tracheal intubation.

The goal of this case report is to present a case of submental tracheal intubation for reconstructive surgery of maxillary and mandibular fractures.

Case Description The patient was a 24-year-old man, body weight 70 kg, American Society of Anesthesiologists physical status I, scheduled for reconstructive surgery of maxillary and mandibular fractures. We obtained peripheral venous access with a 16-gauge needle and the patient was monitored by pulse oximetry, cardioscope, and noninvasive blood pressure. After preoxygenation, anesthesia was induced using propofol, fentanyl, and cisatracurium.

The patient was intubated with a wired silicone 8 mm endotracheal tube (ETT). Correct placement was confirmed by capnography. Anesthesia was maintained with oxygen, nitrous oxide, and isoflurane. A submental incision was made on the right side of the patient. Soft tissues were divulsed until the floor of the mouth was reached. The distal part of the tube without the connector was clamped and exteriorized through the submental access (Figure). The ETT connector was temporarily disconnected so the body of the tube could be pulled through the floor of the mouth by artery forceps and exteriorized through the submental opening. The tube was reconnected to the breathing system and surgery continued without complications. At the end of the procedure, the patient was extubated and the submental incision was sutured.

Discussion This technique provides a secure airway while allowing for an unobstructed surgical field for adequate

reduction and fixation of midface and panfacial fractures. Submental tracheal intubation also avoids the potential complications associated with nasal intubation and tracheostomy, and obviates the need for a tube change during the operation. In addition to facial trauma where temporary intermaxillary fixation (jaw wiring) is required intraoperatively, submental tracheal intubation may also be indicated in patients undergoing simultaneous elective mandibular orthognathic surgery and rhinoplasty procedures, and in cleft lip and palate patients undergoing orthognathic surgery where nasal obstruction may preclude the use of a nasal tube.

The submental access is a simple procedure and technique that has excellent results. Good communication between the surgeon and the anesthesiologist is essential to minimize potential complications. Complications are rare because the area does not have any large vessels or nerves. This provides a clear surgical field and the ability to treat all the injuries in a single surgery. Using this technique, it is possible to perform an intermaxillary fixation without the need for a tracheostomy. In summary, submental tracheal intubation is a useful alternative for airway management in selected patients with complex craniomaxillofacial injuries.

Figure. Tracheal tube with removable connector in the submental region just before suture.

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Managing the Unanticipated Difficult Intubation Due to Epiglottic Cyst DAVID J. KIM, MD, MS

Case Description

Department of Anesthesia, Critical Care and Pain Medicine Massachusetts General Hospital Harvard Medical School Boston, Massachusetts

Epiglottic cysts are rare and constitute only 5% of all benign laryngeal lesions.1 However, the true incidence of epiglottic cysts is unknown as many can be asymptomatic and discovered incidentally during workup of other comorbidities or induction of general anesthesia. Asherson reported an incidence of larger epiglottic cysts of 1 in 4,200 laryngoscopies and Padfield reported a personal incidence of 4 in 5,000 laryngoscopies.2,3 Epiglottic cysts are potentially dangerous and can present at any stage in life. They can cause obstruction of the airway, unexpected difficulty with mask ventilation and intubation, asphyxiation, and sudden death.4-7 The most common symptoms of epiglottic cysts are nonspecific and include voice changes, stridor, dysphagia, and hoarseness. We present a case of an unanticipated difficult intubation due to an epiglottic cyst that was found incidentally during the induction of general anesthesia.

A 59-year-old man with a past medical history significant for hypertension, hyperlipidemia, type 2 diabetes, coronary artery disease with a prior myocardial infarction, obstructive sleep apnea (OSA), and chronic diverticulitis of the sigmoid colon presented for laparoscopic sigmoid colectomy. His previous surgeries included a tonsillectomy in childhood and right knee surgery at a different institution. His daily medications included aspirin 81 mg, gemfibrozil 600 mg, lisinopril 20 mg, simvastatin 20 mg, and metformin 500 mg twice daily.

He used a continuous positive airway pressure (CPAP) machine nightly for OSA. He denied alcohol use but admitted an extensive tobacco history (smoking two packs daily for 46 years).

The airway examination was notable for a Mallampati class I airway. The patient had full range of motion of the neck, good jaw protrusion, thyromental distance of greater than 6 cm, and mouth opening of 4 cm. His voice was hoarse, but he stated it was chronic and attributed it to his smoking history. The remainder of his physical exam was unremarkable.

After premedication with midazolam 2 mg, general anesthesia was induced using propofol 2 mg/kg. The patient was initially a difficult mask ventilation but significantly improved with an size 5 oral airway (100 mm).

After confirmation of adequate mask ventilation,

Figure 1. Visualization of the epiglottic cyst with video laryngoscopy.

Figure 2. Post-intubation view of the epiglottic cyst.

The author reported no relevant financial disclosures.

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rocuronium 0.6 mg/kg was administered for neuromuscular blockade. Direct laryngoscopy with a MAC 3 laryngoscope resulted in a Cormack-Lehane grade 4 view (neither epiglottis nor glottis seen). Mask ventilation was reinitiated with 100% oxygen while a video laryngoscope (VL) was brought into the room.

Visualization via a GlideScope (size 3 Stat; Verathon) showed a pink, cystic mass measuring approximately 2 cm × 1.5 cm, slightly left of midline on the lingual surface of the suprahyoid epiglottis. The mass was broad-based, pedunculated, and ball-valving into the endolarynx (Figure 1). However, we were unable to obtain a view of the larynx even with the VL. Under visualization of the VL, we then advanced an endotracheal tube (ETT) introducer (Portex, Smiths Medical) under the epiglottis with the coudé tip pointing anteriorly. Tactile “clicking” sensations were noted as the tip of the introducer was advanced over the tracheal rings.

We also encountered the familiar “resistance to further insertion” after advancing approximately 8 cm. At this point, a 7.5 mm ETT was advanced over the introducer without difficulty using a Seldinger-like technique, while maintaining visualization with the VL (Figures 2 and 3).

Tracheal intubation was confirmed with bilateral chest rise, auscultation of breath sounds, and the presence of sustained end-tidal carbon dioxide (CO2). The surgical procedure was completed without complication. The patient was extubated at the conclusion of the case and recovered uneventfully in the postanesthesia care unit.

Three months later, the patient underwent suspension microlaryngoscopy, CO2 laser and cold steel simple excision, and decompression of the epiglottic cyst.

Final pathology showed a benign squamous-lined cyst and microscopic component consistent with squamous papilloma (benign epithelial neoplasm). The patient was doing well at follow-up at 10 months, and denied hoarseness, dyspnea, dysphonia, dysphagia, and reflux.

Evaluation using a flexible video nasolaryngoscope showed a small left posterior vocal fold granuloma.

There was normal arytenoid mobility and otherwise

smooth vocal edges bilaterally. There were no masses or ulcerations in the oropharynx, hypopharynx, or larynx.

Discussion Although each of the airway tests (eg, Mallampati classification, thyromental distance, and mouth opening) has limited value on its own, together they can create a more comprehensive picture of expected difficulty with mask ventilation and tracheal intubation in patients presenting for preoperative evaluation.8 It has been reported that a history of previous airway difficulty is the best predictor of subsequent difficult airway.9 Unfortunately, we did not have records of previous anesthetics for our patient. Furthermore, our patient had a relatively reassuring airway exam that was only notable for hoarseness, which could have been attributed to many other causes. It is also possible that his OSA may have been partly due to obstruction secondary to the mass effect of the cyst. He did confirm improved OSA symptoms at follow-up after removal of the epiglottic cyst, although he continued to use CPAP nightly. This case report illustrates the limitations of the airway assessment and the importance of being prepared for the management of an unanticipated difficult airway for any patient.

References 1.

2. Asherson N. Large cysts of the epiglottis: a classification and case records. J Laryngol Otol. 1957;71(11):730-743.

3. Padfield A. Epiglottic cysts: a case report and review. Anaesthesia.

1972;27(1):84-88.

4. Keenleyside HB, Greenway RE. Management of pre-epiglottic cysts: a report of nine cases. Can Med Assoc J. 1968;99(13):645-649.

5. Fang TJ, Cheng KS, Li HY. A huge epiglottic cyst causing airway obstruction in an adult. Chang Gung Med J. 2002;25(4):275-278.

6. Henderson LT, Denneny JC 3rd, Teichgraeber J. Airway-obstructing epiglottic cyst. Ann Otol Rhinol Laryngol. 1985;94(5 Pt 1):473-476.

7.

Epiglottic cyst

New GB, Erich JB. Benign tumors of the larynx: a study of seven hundred and twenty-two cases. Arch Otolaryngol.

1938;28(6):841-910.

Mason DG, Wark KJ. Unexpected difficult intubation. Asymptomatic epiglottic cysts as a cause of upper airway obstruction during anaesthesia. Anaesthesia. 1987;42(4):407-410.

8. Lee A, Fan LT, Gin T, et al. A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway.

Anesth Analg. 2006;102(6):1867-1878.

Epiglottis

9. el-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg. 1996;82(6):1197-1204.

Endotracheal tube L

R

Figure 3. Endotracheal tube is posterior to the cyst. Only the right side of the epiglottis is visualized.

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Lasing Endobronchial Tumors Through a Supraglottic Airway PAOLA VALLS, MD M. JOSE PARRA, MD JOSE A. CARBONELL, MD, EDAIC CARLOS FERRANDO, MD, PHD, EDAIC ESTEFANIA GRACIA, MD F. JAVIER BELDA, MD, PHD Hospital Clinico Universitario de Valencia Valencia, Spain

The Ambu AuraGain device is equipped with a lateral drain tube that prevents esophageal tracheal aspiration.

The device has a sealing pressure of 28 cm H2O, which allows positive pressure ventilation and ensures sealing pressures up to 40 cm H2O without leaks. The absence of an epiglottic lifting bar facilitates intubation through the SGA if necessary, but favors a more comfortable and agile use of the fiber-optic bronchoscope (FOB).

The quality of the vision and management achieved with FOB allow for lasing of endobronchial tumors.

The authors reported no relevant financial disclosures.

Case Description Bronchial intraepithelial lesions may be precursors of central airway lung carcinomas. Early treatment of these pre-invasive lesions might prevent progression to invasive carcinoma. Several studies have shown that endobronchial therapy is associated with a complete response in a considerable percentage of patients who have early central squamous cell carcinoma. However, long-term outcomes remain relatively poor.1 There are different options for the airway management of these patients, from a simple face mask to extracorporeal oxygenation. The use of a supraglottic airway (SGA) device is an alternative to tracheal intubation and rigid bronchoscopy procedures that does not require instrumentation for the airway.2

Figure 1. Obstruction of the right main bronchus airway.

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A 54-year-old woman was scheduled for laser bronchoscopy of endobronchial tumor. Preoperative FOB showed a total obstruction of the right main bronchus airway (Figures 1-3).

The procedure was performed under total IV anesthesia. The SGA was used for volume-controlled positive pressure ventilation, and for guiding the FOB through the working channel. Leakage due to the FOB occurred but did not affect ventilation. We maintained normal values of EtCO2 (end-tidal carbon dioxide) during the

Figure 2. View through fiber-optic bronchoscopy.

procedure—monitored via the anesthesia machine— with expiratory tidal volume between 6 and 8 mL/kg.

We set a positive end-expiratory pressure of 5 cm H2O to avoid alveolar collapse and to oxygenate with a low fraction of inspired oxygen, which is required for endobronchial lasing. The minimal peripheral oxygen saturation was 96%.

Postoperative computed tomography scan showed a marked reduction of the endobronchial tumor with significant alveolar reexpansion.

Recommendations Although studies have shown that other SGAs can be used to safely perform complex thoracic surgery procedures, such as the placement of a bronchial blocker under direct visualization through the FOB, the AuraGain device offers several advantages for endobronchial lasing compared with techniques like rigid bronchoscopy3:

• Gastric drainage capacity minimizes risk for gastric insufflation • Possibility of tracheal intubation and FOB • High sealing pressures ensure effective positive pressure ventilation in cases of airway obstruction • Less anesthetic requirements compared with rigid bronchoscopy

References 1.

Wisnivesky JP, Yung RC, Mathur PN, et al. Diagnosis and treatment of bronchial intraepithelial neoplasia and early lung cancer of the central airways: Diagnosis and management of lung cancer, 3rd ed. American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2013;143(5 Suppl):e263S-e277S.

2. Brimacombe JR, Berry A. The incidence of aspiration associated with the laryngeal mask airway: a meta-analysis of published literature. J Clin Anesth. 1995;7(4):297-305.

3. Arévalo Ludena J, Arcas Bellas JJ, López Pérez V, et al. Placement of a bronchial blocker through the I-gel supraglottic airway device from single-lung ventilation: preliminary study. Rev Esp Anestesiol Reanim. 2010;57(8):532-535.

Figure 3. Perioperative fiber-optic bronchoscopy showing airway obstruction.

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Difficult Airway in Patients With Head or Neck Masses NORMA DOMINGUEZ, DO, FAOCA Program Director Anesthesia Residency Program Riverside County Regional Medical Center Moreno Valley, California

MAULIK RAJYAGURU, DO CA-2 Anesthesia Residency Program Riverside County Regional Medical Center Moreno Valley, California

PATRICIA LOWERY, DO CA-2 Anesthesia Residency Program Riverside County Regional Medical Center Moreno Valley, California

MACKENZIE PULLEE, DO PGY-1 Grandview Medical Center Dayton, Ohio The authors reported no relevant financial disclosures.

Case Description A 52-year-old woman was admitted to the ear, nose and throat (ENT) service for compressive symptoms of the airway secondary to a large anterior neck mass. The patient reported an 8-month history of a progressively enlarging neck mass that had gone previously unevaluated. Precipitating the patient’s current hospital visit were symptoms of increased shortness of breath while supine, stridor, and dysphagia limiting solid food intake.

Review of systems was otherwise negative except for dysphonia and subjective weight loss. The patient’s past medical history was limited to hypothyroidism. Social history revealed that the patient smoked 15 cigarette packs per year, ceasing one week prior to presentation.

The patient showed signs of increased respiratory work and intermittent oxygen desaturations while sleeping through the first night of admission. Tracheostomy and biopsy were scheduled for the next day in anticipation of acute respiratory failure. ENT surgeons emphasized that emergent tracheostomy would not be possible because of the large size of the neck mass (7 cm × 8 cm) located anterior to the cricothyroid membrane. Preoperative bronchoscopy ruled out any upper pharyngeal anomalies, but slight vocal paresis was noted.

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A computed tomography (CT) scan of the neck showed a moderate to severe narrowing of the trachea and enveloping of the right common carotid artery.

There was significant concern regarding the patency of the trachea and the size of the tube that would pass the narrowed opening. The patient was notably anxious and tachypneic in preoperative holding. An awake fiber-optic intubation was planned due to presumed tracheal stenosis secondary to tumor mass effect.

In preparation for an awake intubation, glycopyrrolate 0.3 mg IV and 4 sprays of 20% benzocaine were administered to decrease airway secretions and anesthetize the oral cavity, respectively. Nerve blockade was not possible due to the large size and location of the mass. The patient developed significant anxiety and increased respiratory effort during transfer to the operating room (OR), and was unable to lie supine. Once in the OR, she developed tachycardia and decreased oxygen saturation (SpO2). The patient required positive pressure ventilation to return SpO2 to greater than 95%. Once SpO2 stabilized, Ovassapian airway insertion was attempted to facilitate fiber-optic intubation, which she tolerated poorly.

After 15 minutes of verbally attempting to calm the patient in the OR, she developed worsening hypoxia and hypercapnia, followed by confusion. Thereafter, the patient exhibited seizure activity for approximately 30 seconds with generalized movement of all 4 extremities. Coincident rotatory nystagmus and involuntary loss of bladder control substantiated a preliminary diagnosis of a generalized tonic-clonic seizure. No attempt to abort the seizure was made for fear of airway compromise with sedation and the short duration of activity. At this time, SpO2 decreased transiently to 65% and end-tidal carbon dioxide (EtCO2) increased to approximately 85 mm Hg. Tracheal stenosis and the lack of sedation or paralysis made positive pressure ventilation difficult. Despite this, SpO2 slowly rose to greater than 90% with normal range EtCO2 using bagmask ventilation.

The etiology of the seizure activity was unclear at the time. Hypoxia and/or hypercapnia were highly suspected and local anesthetic toxicity was a concern.

An emergent airway needed to be established. A laryngeal mask airway was not feasible due to the high pressures needed to ventilate the patient, and an emergency tracheostomy was not possible due to the neck mass. Endotracheal intubation was attempted via

direct laryngoscopy without sedation, which elicited a grade 4 view. A second attempt with a bougie was promptly aborted as SpO2 began to quickly drop to about 70%. After approximately 10 minutes, reinstitution of bag-mask ventilation raised the patient’s SpO2 level to greater than 90% and reversed hypercapnia.

Shortly after the second attempt at laryngoscopy, the patient exhibited similar seizure activity for approximately 30 seconds. The patient remained without sedation or paralysis to avoid possible airway collapse.

The ENT team then made 2 attempts at direct oral laryngoscopy/intubation, without success. The patient became increasingly agitated and confused, and tachycardic up to 170 beats per minute. After administration of IV metoprolol, her vital signs returned to normal limits. Midazolam 0.5 mg IV was given at this point. An attempt to intubate using the GlideScope (Verathon) failed due to the anatomy of the airway. The team was eventually able to successfully place a size 6.5 nasotracheal tube through the left nare with the combination of a GlideScope and a fiber-optic scope—a fiber-optic with a video monitor was not available (Figure 1).

The patient’s tachycardia and oxygen desaturations soon resolved after intubation. The patient developed hypotension approximately 10 minutes after intubation.

The tracheostomy procedure was decidedly aborted secondary to persistent hypotension. The nasotracheal tube was further secured; an arterial line was placed in the OR; and the patient was transferred to the surgical ICU and stabilized with ventilator support. Postoperative chest x-ray demonstrated development of mild

Figure 1. Improvising using a GlideScope as a video monitor for the fiber-optic scope.

to moderate bilateral perihilar and lower lobe infiltrates which were not present preoperatively.

Preoperative Care Patients with head or neck masses deserve special anesthetic consideration. Perioperative management needs to be individualized to the patient and depends on comorbidity. As witnessed in this situation, the choice of perioperative management is often appropriately weighted toward time-sensitive, life-threatening complications; it is imperative to have a comprehensive preanesthetic evaluation.

As exhibited by the clinical picture in this patient, head and neck cancer can cause site- and organ-specific complaints (Figure 2).1 An appropriately focused patient history that includes drug abuse, alcohol use, smoking, and previous airway-related problems should be obtained.

Similarly, indicators that help to predict a potentially difficult airway include changes in voice and history of dyspnea or dysphagia.2,3 History of dyspnea in the supine position, but not in the lateral or prone position, suggests the presence of a pharyngeal, neck, or anterior mediastinal mass.4 As elicited during a patient interview, a coarse, scratchy voice indicates a glottic obstruction, but a muffled voice suggests a supraglottic obstruction.4 Further assessment includes careful physical examination of tissue in the anterior triangle of the neck. Congruent with our patient’s intraoperative course, a large thyroid or anterior neck mass can present resistance to manipulation during tracheal intubation. Hence, a difficult tracheal intubation was anticipated.

Preoperative investigations germane to the patient’s clinical condition and associated illness are essential for proper perioperative management of the patient.5 In

Figure 2. The patient’s neck mass.

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general, the presence of an anterior neck mass is associated with thyroid and calcium level abnormalities.6 Consequently, electrolyte levels and thyroid function tests should be thoroughly evaluated.

Assessment of nutritional status is prudent for patients with head and neck cancer. In a non–mutually exclusive fashion, malnutrition has been reported among patients with airway compromise as well as head and neck cancer.7-9 Liver function tests may be warranted as patients with long-standing obstructive symptoms may be especially malnourished. Moreover, lower serum albumin secondary to malnutrition may affect anesthetic drug pharmacodynamics.10 Spirometry can be useful in distinguishing dyspnea secondary to an upper airway mass versus a chronic obstructive process.11,12 As in our patient, preoperative bronchoscopy can provide more pertinent information by allowing direct observation of tracheal stenosis and right vocal cord paresis.11-13 Involvement of the recurrent laryngeal nerve can cause narrowing at the glottic opening in addition to direct mass compression of the trachea.13 CT of the head, neck, and chest were reviewed to rule out the presence of an additional mass in the mediastinum and pharynx. It was imperative to rule out any additional etiologies of airway obstruction because some larger tumors, like our patient’s,

may cause tracheal compression and render intubation extremely difficult.1,2,13

Airway Management Challenges such as a shared operative field and exacerbation of airway obstruction need to be accounted for throughout the perioperative visit. Airway management in patients with obstructive pathology often present to the OR with conditions that make tracheal intubation difficult. Anesthetizing such a patient without securing the airway first may lead to irreversible consequences.9 Our patient was given minimal sedation to decrease the chance of airway collapse.

Most providers might agree that an awake fiberoptic intubation is the approach with the highest likelihood of success for this patient. However, this proved to be difficult due to the patient’s anxiety and worsening dyspnea. Even with optimal verbal preparation and comfort, some patients may not tolerate such a procedure, especially with concurrent shortness of breath.

With multiple approaches by anesthesiologists and ENT surgeons, we were able to improvise the GlideScope as a video monitor for the fiber-optic scope to allow us to successfully intubate. This technique may aid in identification of landmarks and intubation when a fiber-optic with a video monitor is not available.

References 1.

Dougherty TB, Clayman GL. Airway management of surgical patients with head and neck malignancies. Anesthesiol Clin North Am. 1998;16(3):547-562.

2. Donlon JV Jr. Anesthesia for eye, ear, nose and throat surgery. In: Miller RD, ed. Anesthesia. 4th ed. New York, NY: Churchill Livingstone; 1994:2175-2196.

3. Supkis DE Jr, Dougherty TB, Nguyen DT, et al. Anesthetic management of the patient undergoing head and neck cancer surgery. Int Anesthesiol Clin. 1998;36(3):21-29.

4. Ovassapian A. Management of the difficult airway. In: Ovassapian A, ed. Fiberoptic Endoscopy and the Difficult Airway. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 1996:201-230.

5. Roizen MF. Preoperative evaluation. In: Miller RD, ed. Anesthesia.

3rd ed. New York, NY: Churchill Livingstone; 1990:743-772.

6. Ralston SH. Pathogenesis and management of cancer associated hypercalcaemia. Cancer Surv. 1994;21:179-196.

7.

Goodwin WJ Jr, Byers PM. Nutritional management of head and neck cancer patient. Med Clin North Am. 1993;77(3):597-610.

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8. Goodwin WJ Jr, Torres J. The value of prognostic nutritional index in the management of patients with advanced carcinoma of the head and neck. Head Neck Surg. 1984;6(5):932-937.

9. Hooley R, Levine H, Flores TC, et al. Predicting postoperative head and neck complications using nutritional assessment: the prognostic nutritional index. Arch Otolaryngol. 1983;109(2):83-85.

10. Latto IP. Management of difficult intubation. In: Latto IP, Rosen M, eds. Difficulties in Tracheal Intubation. London, England: Bailliere Tindall; 1985:99-141.

11. Harrison RA. Respiratory function in anesthesia. In: Barash PG, Cullen BF, Stoelting RK, eds. Clinical Anesthesia. Philadelphia, PA: JB Lippincott; 1990:902.

12. Marsh HM. Anesthesia for patients with chronic pulmonary disease.

In: Hershey SG, ed. ASA Refresher course. Philadelphia, PA: JB Lippincott; 1984:133-149.

13. Jensen NF, Benumof JL. The difficult airway in head and neck tumor surgery. Anesthesiol Clin North Am. 1993;11: 475-511.

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Challenges of Exchanging A Laryngeal Tube for an Endotracheal Tube MICHAEL KUSHELEV, MD Assistant Professor of Anesthesiology Ohio State University Wexner Medical Center Columbus, Ohio The author reported no relevant financial disclosures.

A wide variety of supraglottic airway devices have been validated for use in pre- and in-hospital settings as a primary method for securing the airway, and as a rescue device after failed intubation.1,2 The King LTS-D (Ambu) is a laryngeal tube (LT) designed to allow positive pressure ventilation and to pass a suction catheter into the esophagus (Figure 1). Practitioners can be faced with the challenge of exchanging a King LTS-D for a more definitive airway device in anticipation of a prolonged need for mechanical ventilation. This case report highlights the difficulties of exchanging an LT for an endotracheal tube (ETT) for definitive airway management.

of anterior displacement on flexion (Figure 1). A CT scan previously demonstrated an odontoid fracture with atlantoaxial rotary subluxation with the right lateral mass of C1 displaced lateral to C2 and posterior displacement of the posterior arch of C1 relative to C2 causing canal narrowing to approximately 1.2 cm.

Initial attempts were made to exchange the size 3 King LTS-D over an Aintree Intubation Catheter (AIC, Cook Medical) mounted on a fiber-optic bronchoscope (FOB), as previously described in the literature (Figure 2).3,4 Despite repeated attempts, including lubrication and positioning adjustments of the LT, the FOBAIC combination would not pass through the King LTS-D. An extraluminal technique through a nasal route was not attempted due to concern for coagulopathy, given the patient’s recent history of spontaneous gastrointestinal

Case Description A 71-year-old woman of normal body habitus with severe rheumatoid arthritis (RA) presented with newly diagnosed upper gastrointestinal bleeding and altered mental status with computed tomography (CT) scan finding a nonhemorrhagic stroke. The patient was admitted to the ICU and intubation was attempted for airway protection. Following 4 failed attempts at intubation with direct and video laryngoscopy, a size 3 King LTS-D was placed, resulting in effective oxygenation and adequate ventilation. However, the patient’s ventilation became more difficult several hours after LT placement, with maximal tidal volumes of 200 to 300 mL and increasing supplemental oxygen requirements.

Anesthesiology was consulted to exchange the LT for a more definitive airway.

After examining the patient and reviewing her past medical history and medical records, it was noted that the patient had an extremely small oral opening, limited neck extension—presumably secondary to longstanding RA—and a protruding enlarged tongue. During a previous hospitalization, flexion and extension plain films demonstrated atlantoaxial instability with 3 mm

Figure 1. Cervical spine x-rays showing atlantoaxial instability.

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bleeding.3,5 The King LTS-D was removed from the mouth and the significance of the tongue engorgement was noted. A size 4 i-gel (Intersurgical) laryngeal airway was placed easily and a FOB-AIC combination was used to place a 6.0 ETT into the trachea through the i-gel without difficulty.

LTs are increasingly being used for establishing an airway in emergency situations.6-8 LT placement is highly successful and can be accomplished more quickly than an ETT. 9,10 For patients requiring prolonged airway support, practitioners can encounter difficulties with exchanging the LT for a more stable airway.

Our patient developed massive lingual engorgement similar to a report by Gaither et al, presumably due to obstruction of venous drainage by the oropharyngeal balloon.11 Presence of lingual edema can substantially limit the airway options available. Human and mannequin studies have shown a high rate of success of intraluminal exchange techniques using a FOB-AIC combination.4,5 However, these studies have employed sizes 4 and 5 King LTS-D. Our patient had a size 3 King LTS-D in situ that did not allow passage of AIC. In fact, we have found it is impossible to insert an AIC through a size 3 King LTS-D. We found significant difficulty, with a need for lubrication and manipulation, to pass an AIC through a size 4 King LTS-D, independent of patient factors.

Conclusion Although placement of an LT is gaining popularity among pre-hospital medical personnel, and in cases of emergent airway difficulties, particular challenges should be anticipated when attempting to exchange the LT for an ETT. Our experience highlights the possibilities of lingual edema and the inability to pass an AIC through a size 3 King LTS-D. Clinicians may face a very difficult choice when considering removing a suboptimal airway in exchange for a more definitive ETT.

References 1.

Frascone RJ, Russi C, Lick C, et al. Comparison of prehospital insertion success rates and time to insertion between standard endotracheal intubation and a supraglottic airway. Resuscitation.

2011;82(12):1529-1536.

2. Frascone RJ, Wewerka SS, Burnett AM, et al. Supraglottic airway device use as a primary airway during rapid sequence intubation.

Air Med J. 2013;32(2):93-97.

3. Asai T, Shingu K. Use of the laryngeal tube for nasotracheal intubation. Br J Anaesth. 2001;87(1):157-158.

4. Genzwueker H, Vollmer T, Ellinger K. Fiberoptic tracheal intubation after placement of the laryngeal tube. Br J Anaesth.

2002;89(5):733-738.

5. Budde AO, Schwarz A, Dalal PG. Comparison of 2 techniques of laryngeal tube exchange in a randomized controlled simulation study. Am J Emerg Med. 2015;33(2):173-176.

6. Guyette FX, Wang H, Cole JS. King airway use by air medical providers. Prehosp Emerg Care. 2007;11(4):473-476.

7.

Russi CS, Hartley MJ, Buresh CT. A pilot study of the King LT supralaryngeal airway use in a rural Iowa EMS system. Int J Emerg Med. 2008;1(2):135-138.

8. Schalk R, Meininger D, Ruesseler M, et al. Emergency airway management in trauma patients using laryngeal tube suction. Prehosp Emerg Care. 2011;15(3):347-350.

9. Hubble MW, Wilfong DA, Brown LH, et al. A meta-analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates. Prehosp Emerg Care.

2010;14(4):515-530.

Figure 2. Advancement of an Aintree catheter with a fiber-optic scope through a King LTS-D.

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10. Burns JB Jr, Branson R, Barnes SL, et al. Emergency airway placement by EMS providers: comparison between the King LT supralaryngeal airway and endotracheal intubation. Prehosp Disaster Med. 2010;25(1):92-95.

11. Gaither JB, Matheson J, Eberhardt A, et al. Tongue engorgement associated with prolonged use of the King-LT laryngeal tube device. Ann Emerg Med. 2010;55(4):367-369

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Direct Fiber-Optic Endotracheal Intubation for a Deformed Airway MICHAEL B. MEYERS, MD Assistant Professor of Anesthesiology Hofstra University Medical School Hempstead, New York Dr. Meyers is a scientific consultant for Paion AG. He is also the president and CEO of Meyers & Gerard Medical LLC.

Case Description The patient was a man aged in his mid-50s undergoing radiation therapy and surgery for unknown head and neck cancer, possibly tonsillar cancer. He presented in respiratory failure in the medical ICU (MICU) on a non-rebreather 100% oxygen mask and nitric oxide (NO) 20 ppm. Multiple attempts were made by the MICU staff to intubate without success. Each time NO was discontinued, the patient’s oxygen saturation would fall into the 50%-60% within 30 seconds and cardiac arrythmias would occur.

The first direct laryngoscopy by the anesthesia attending revealed absence of any definable anatomic landmarks and some evidence of recent trauma. The patient was rapidly becoming fatigued and mechanical ventilation was needed. We administered a small amount of propofol and verified our ability to bag mask-ventilate the patient.

The patient was then placed on propofol sedation and a size 4 i-gel (Intersurgical) supraglottic airway was inserted without difficulty. The patient was bagventilated with NO and oxygen via Ambu bag, at a flow rate of 10 L per minute via the i-gel airway. A 7-mm endotracheal tube (ETT) was placed midway down the laryngeal mask airway and the cuff was inflated, sealing the ETT tube within the airway. A fiber-optic (FO) adapter was placed on the ETT and the NO adapter was placed in line, thereby allowing the patient to be ventilated (by a mechanical ventilator) via the ETT placed within the supraglottic airway.

With the patient completely sedated and ventilated with 100% oxygen and NO 20 ppm, a FO scope was placed through the adapter, passing through the ETT first and then the supraglottic airway. After several minutes of suctioning and evaluation, an area that was somewhat identifiable as a glottic aperture was seen.

The FO scope was passed through this opening and tracheal rings were identified. The cuff was released on the ETT and it was passed atraumatically through the glottic opening over the FO scope. The cuff was then inflated, the ETT adapter was removed, and the pilot balloon was inserted into the ETT opening. A second 7-mm tube was used as a “pusher” as the i-gel airway was removed over the tube, and the ETT adapter was then reattached. The tube was secured following confirmation of positioning by the FO scope and the patient was then placed on mechanical ventilation with NO. This technique allowed for as much time as needed to examine and visualize a deformed airway and intubate the patient without fear of recurrent hypoxic episodes or cardiovascular instability secondary to either hypoxia or anxiety on the part of the patient (or the attending).

Figure. Ventilated anesthetized direct fiber-optic intubation.

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Importance of Oropharyngeal Hygiene for Nonintubated Patients in the ICU SHANE V. CHERRY, MD Resident Physician Jackson Memorial Hospital University of Miami Miller School of Medicine Department of Anesthesiology, Perioperative Medicine, and Pain Management Miami, Florida

CHRISTIAN DIEZ, MD, MBA Assistant Professor of Clinical Anesthesiology University of Miami Miller School of Medicine Department of Anesthesiology, Perioperative Medicine, and Pain Management Miami, Florida The authors did not report any relevant financial disclosures.

The medical literature has an abundance of research and clinical guidelines in regard to the oral care of intubated critically ill patients. These guidelines emphasize the importance of practices, such as chlorhexidine mouthwash and subglottic suctioning, as a means to decrease the incidence of ventilator-associated pneumonia.1 However, little attention has been given to the importance of oral care in nonintubated critically ill patients and the role that might play in preventing complications associated with securing the airway emergently.

Case Description A 53-year-old man was transferred from the Dominican Republic to the ICU in Ryder Trauma Center at Jackson Memorial Hospital for further management of multiple orthopedic injuries. He sustained the injuries as a restrained driver in a motor vehicle collision 1 week earlier.

His medical history was significant for morbid obesity (body mass index, 54 kg/m2), obstructive sleep apnea not on continuous positive airway pressure, and non–insulin-dependent diabetes. Of particular interest, the patient had surgery for a broken leg approximately 5 years earlier. That surgery was complicated by difficult intubation, difficulty weaning from mechanical ventilation, and subsequent vocal cord problems necessitating rehabilitation. However, during his stabilizing

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treatment in the Dominican Republic, which included placement of an external fixation system on his right lower extremity, he was successfully intubated and subsequently extubated before his transfer to our facility.

According to the patient’s family, this was again a difficult intubation and weaning process.

Upon arrival to the trauma center, his vital signs were stable; he was maintaining his oxygen saturation on room air; and had a Glasgow Coma Scale score of 15. Although his movement was limited by pain, sensation and motor function were intact throughout all 4 extremities. However, the patient had a short, thick neck, and the cervical collar he was wearing limited his range of motion. Upon exam, he had a Mallampati class II airway and intact dentition. Cardiac and pulmonary exams were unremarkable. Upon further radiographic workup, it was discovered that the patient had a nondisplaced C6 vertebral body fracture, multiple lumbar spine fractures, and fractures of the bilateral lower extremities and right upper extremity.

After admission, the anesthesiology department was consulted for airway management as part of an elective tracheostomy. Due to the expectation for multiple orthopedic procedures and the patient’s history of difficult intubation and subsequent vocal cord problems, the patient strongly requested an elective tracheostomy in order to avoid the risks associated with repeated intubations and prolonged oral intubation.

After extensive discussion between the patient, surgical team, and anesthesiology department, this was deemed a reasonable request and preparations were made for an awake fiber-optic intubation (FOI) in the operating room (OR) prior to open tracheostomy. The patient’s airway was topicalized upon arrival to the OR. An Ovassapian airway was inserted and resistance was felt. A recognizable view could not be obtained with attempted advancement of the fiber-optic scope.

A Yankauer was inserted to attempt deep suctioning, and a hard mass was detected deep in the patient’s hypopharynx. We were unable to remove this mass until the attending anesthesiologist reached in to assist with his fingers. He removed a large, inspissated mass of mucus/saliva (Figure) measuring 3 inches long and 1.25 inches wide. The airway was successfully secured

via awake FOI after removal of the mass, and the asleep tracheostomy proceeded without any further complications.

Oral Hygiene Protocol This case illustrates the importance of adequate oral hygiene in nonintubated critically ill patients. The medical literature has an abundance of information on oral care and guidelines for intubated patients.1-3 However, to the best of our knowledge, the same does not exist for nonintubated critically ill patients. Some of the same practices can be adopted for this patient population— which can have injuries and illnesses that place patients at high risk for poor oral hygiene and copious, inspissated secretions—and could play a crucial role in preventing complications associated with securing the airway emergently.

All anesthesiologists may encounter this situation at some point when called for airway management in the ICU. Some of the factors responsible include repeated NPO (nothing by mouth) status as a patient is scheduled for surgery but then the surgery is canceled due to the ICU’s dynamic nature, significant pain resulting in splinting, poor respiratory effort, and an inability to properly expel airway secretions. Without adequate bedside care, there is a potential risk for disastrous complications should the airway need to be secured emergently, particularly under nonoptimal conditions such as those frequently encountered in an ICU. In this case, the index patient had been hospitalized for over a week prior to his attempted intubation in the OR. We believe the mass found in this patient’s hypopharynx could have been prevented with adequate oral care (eg, routine suctioning of secretions and periodic hydration of the oral cavity with mouth swabs). Our patient fortunately avoided compromise because of the nonemergent nature of the airway and method of intubation. However, under different circumstances, it is easy to envision a scenario where this mass could have been inadvertently advanced further into the airway with either a laryngoscope blade or a supraglottic airway, resulting in a “cannot intubate, cannot ventilate” scenario.

with mouth swabs, avoidance of unnecessary NPO, and periodic suctioning. All suction equipment should meet the recommendations of the Anesthesia Patient Safety Foundation: Anesthesia suction equipment should have the ability to clear a minimum of 2.5 to 4 L/min of water, which corresponds to a pressure at the tip of the Yankauer of –100 to –200 mm Hg.4 Following these simple steps would make airway intervention safer in this high-risk patient population.

References 1.

Berry AM, Davidson PM, Nicholson L, et al. Consensus based clinical guideline for oral hygiene in the critically ill. Intensive Crit Care Nurs. 2011;27(4):180-185.

2. Feider LL, Mitchell P, Bridges E. Oral care practices for orally intubated critically ill adults. Am J Crit Care. 2010;19(2):175-183.

3. Saddki N, Mohamed Sani FE, Tin-Oo MM. Oral care for intubated patients: a survey of intensive care unit nurses. Nurs Crit Care.

2014 Oct 28. [Epub ahead of print] 4. Paulsen AW. Are there guidelines for anesthesia suction? APSF Newsletter. 2015;29(3):58-60.

Conclusion We believe all ICUs should have a unit-driven oral hygiene protocol for nonintubated critically ill patients.

At a minimum, it would include periodic oral hydration

Figure. 3-inch–long mass removed from patient’s hypopharynx.

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Use of Channeled-Blade Video Laryngoscope as Rescue Following Failed Intubation EUGENIO MARTÍNEZ HURTADO, MD, AND JAVIER RIPOLLÉS MELCHOR, MD Consultant Anesthesiologists Hospital Universitario Infanta Leonor Madrid, Spain

PAULA MARTÍNEZ FARIÑAS, MD Consultant Anesthesiologist Hospital Universitario Infanta Cristina Madrid, Spain

MIRIAM SÁNCHEZ MERCHANTE, MD Consultant Anesthesiologist Hospital Universitario Fundación Alcorcón Madrid, Spain The authors reported no relevant financial disclosures.

Case Description In an attempt to prevent further degeneration and possible development of esophageal cancer, a 47-yearold woman with Barrett’s esophagus is scheduled for Nissen fundoplication under general anesthesia. She is 159 cm tall, weighs 84.2 kg, and presents as ASA (American Society of Anesthesiologists) II with a body mass index of 33.3 (representing mild obesity). Her medical history includes no known drug allergies; arterial hypertension and dyslipidemia; negative for diabetes mellitus; anxiety; adenopathy; regurgitation and pulmonary aspiration; and first pregnancy was stillborn. She does not drink alcohol and is an ex-smoker, having quit just 2 months before.

Her surgical history includes an appendectomy at age 14, hysterectomy with double adnexectomy for a left ovarian cyst and fibroids with positive markers, and a tonsillectomy. She underwent 2 caesarean deliveries under epidural anesthesia. Her regular prescriptions include rabeprazole (Pariet, Eisai), cidine, and escitalopram (Lexapro, Actavis). Her family medical history is notable for her father who has gastric cancer.

Presurgery airway history using Arné multivariate findings includes Mallampati score of class I, thyromental distance (TD) of 9 cm, mobility of the head and neck >100º, and mouth opening >4 cm. Total Arné score is 3

(<11). Khan test is 3 and the neck circumference (NC) is 43 cm, so the NC/TD ratio is 4.78 (43 cm/9 cm).

From the history and physical findings, no difficult airway was suspected.

After preoxygenation and IV induction with muscle relaxation, we checked for easy ventilation with the facial mask. Our first intubation attempt was with a Macintosh direct laryngoscope (blade #3), achieving a Cormack-Lehane grade 3 view with glottic edema caused by an unknown lymphoid tumor at the lateral aspect of the throat, which prevented view of the left vocal cord and arytenoid. After removing the laryngoscope and while the King Vision video laryngoscope (VL; upper channel, Ambu) was prepared, we vented the patient and optimized her positioning.

Our second attempt was with a King Vision channeled blade, achieving a Cormack-Lehane grade 2 view (Figure 1, a) that improved to Cormack-Lehane grade 1 after employing the BURP (ie, backward, upward, rightward pressure) technique (Figure 1, b and c). Tissues were very friable, and at this point began to bleed (Figure 1, d). To avoid making more manipulations, we used a Frova bougie (Cook) through the endotracheal tube (ETT; Figure 1, e). Finally, we intubated with a Frova bougie without a problem (Figure 1, f and g). The extubation was performed in the operating room without any trouble.

After surgery, the patient was referred to an otolaryngologist for further study of the mass.

Discussion Tracheal intubation is a critical moment of the anesthetic procedure, with 30% of total adverse incidents ascribed to anesthesia being related to difficulties of airway control. In addition, 70% of these accidents result in death or permanent brain damage.1 Intubation difficulty in clinical practice occurs unexpectedly. According to the literature, this can happen in 4% to 5% of those cases in which anesthesia has been induced and the administration of the muscle relaxant has occurred. There is good evidence of the utility of video laryngoscopy as a rescue technique following difficult direct laryngoscopy.2 Because of the design of VLs, there is no need to align the oral axis, meaning less force is required to align the pharyngeal and laryngeal axes, which results in less

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dental trauma and a reduced need to flex or extend the neck. With video laryngoscopy there is a reduced need to use a bougie or external laryngeal manipulation to achieve intubation.

In the current case, after failing to intubate with the Macintosh laryngoscope and after checking for easy ventilation, we decided to rescue using a channeledblade VL. It is important to consider the increase in morbidity that results from a second attempt with direct laryngoscope during intubation.3 In at least 2 studies with large sample sizes, intubation with a VL succeeded in 94% and 99% of cases, respectively, after direct laryngoscopy had failed.4,5 The ASA guidelines also state that video laryngoscopy is a safe means by which to rescue a failed intubation.6 VLs are not a homogeneous class. They differ in design, technical conďŹ guration, and monitor and blade type, requiring the user to become familiar with each device before use in a difficult airway situation. The main difference in VLs arises from the type of blade, and many different types are currently available. There are 3 main categories of VLs7-9: 1. Macintosh blade-shaped optical laryngoscopes: These devices (eg, C-MAC,Karl Storz or McGrath

a

MAC, Aircraft Medical/Covidien) have blades shaped like a Macintosh laryngoscope but are combined with video technology. The video screen is helpful, as anyone assisting with intubation is able to visualize the procedure and target his or her actions accordingly. The insertion method is similar to the conventional Macintosh laryngoscope, and it is possible to see the glottis either directly or on a video screen. Successful intubation is achieved more frequently when compared with the Macintosh laryngoscope, but the use of a tube introducer and external pressure to the larynx are frequently required to obtain a clear view of the glottis.10 2. Anatomically shaped blade without a tube guide: This group includes the GlideScope (Verathon), McGrath X blade (Aircraft Medical), D-BLADE (Karl Storz), and King Vision nonchanneled blade (Ambu), and so forth. The blade is anatomically shaped, giving a view of the glottis without the need to flex or extend the neck. These VLs provide only an indirect view of the glottis, and a preshaped stylet needs to be placed into the tracheal tube before intubation. A limitation of this type of VL is that, if the glottis is only seen indirectly during tracheal tube insertion, there is a moment when its tip

b

e

c

f

d

g

Figure 1. a, C-L grade 2 view achieved; b and c, Following BURP manipulation, a C-L grade 1 view; d, Tissues begin to bleed; e, Frova bougie used through endotracheal tube; f and g, Intubation achieved.

BURP, backward, upward, rightward pressure; C-L, Cormack-Lehane Image used with permission from authors.

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cannot be seen. Upper airway—particularly pharyngeal—trauma may occur at this point. In addition, because of the indirect visualization of the glottis and the need for a preshaped stylet in the tracheal tube, there are occasions when even though there is a clear view of the laryngeal inlet on the video screen, it can be difficult to direct a tube toward the glottis.

3. Anatomically shaped blade with a tube guide: VLs in this group, such as the Airtraq (Prodol Meditec/Teleflex) and King Vision channeled blade (Ambu), have an anatomically shaped blade with a guiding channel that directs the tracheal tube toward the glottic opening. Because the tip of the tube is captured on the video screen even before insertion of the device, the location of the tube tip can be seen continuously during the course of tracheal intubation.

All these types of VLs provide a “look around the corner” to achieve optimal visualization of the glottis

without further manipulation of the patient, and without the need for alignment of the oropharyngolaryngeal axis.

The laryngeal view is usually greatly improved with VLs and, most importantly, in patients with poor laryngeal view using conventional direct laryngoscopy (Cormack-Lehane grade 3 or 4), the glottis view is usually improved to Cormack-Lehane grade 1 or 2.

However, achieving a Cormack-Lehane grade 1 view during video laryngoscopy does not guarantee successful intubation.11 With indirect video laryngoscopy, despite optimal glottic visualization, the most difficult part of the procedure is to enter the curved tube into the glottic entrance and to advance it into the trachea. This could also happen to experts, of whom the accomplishment of the intubation depends more on the ability of the person and on the characteristics of the patient than on the device itself.12 Trying to solve this problem, the channeled-blade VLs help to guide the tube to the trachea without airway

Twist clockwise

Twist counterclockwise

a1

b1

a2

b2

c1

c2

Figure 2. Manipulations of the VL (top) result in subtle movements of the device that can ease intubation (bottom). Here, an Airtraq is rotated (a1 and a2, b1 and b2, and c1 and c2) to orient to the vocal cords.

VL, video laryngoscope Image courtesy of Prodol Meditec.

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manipulation. Despite these capabilities, it is sometimes impossible to orient the tube, which stops at the right arytenoid or continues to the esophagus. In this case, we have to consider the oxygenation status of the patient.

If it is good, we can use a transglottic device (eg, Frova, Eschmann, etc) through the ETT and guide the intubation. Another choice would be to use a fiber-optic bronchoscope through the tube for the same purpose.

However, in some patients intubation may be difficult despite the use of channeled VLs, and finding that the ETT strikes the right arytenoid or goes into the esophagus. Whenever we have a good glottic visualization and the patient remains stable, we can make subtle movements of the device (Figure 2) or the ETT (Figure 3) that will ease the intubation. If oxygenation is correct, we can use a transglottic device (eg, Frova, Eschmann,

etc) or fiber-optic bronchoscope through the ETT. There have been many reviews of VLs that have examined their improvements in view, their rates of intubation success at first attempt, and the time it takes to achieve intubation, as well as complications from the technique.13 Some of their advantages and disadvantages are highlighted in the Table. The most convincing literature to date supports the use of VLs in unanticipated, difficult, or failed laryngoscopy.7 Several of these devices have high intubation success rates in this clinical scenario.8 Thanks to all of these advantages, VLs are becoming more popular. Nowadays, we can find them not only in operating rooms but also in ICUs, emergency departments, and so forth. VLs are also one of the first options cited in the ASA difficult airway algorithm when there is proper ventilation but a difficult intubation.6

Corkscrew ETT counterclockwise

a1

b1 ETT tip goes left and posterior

a2

b2

Corkscrew ETT clockwise

c1 ETT tip goes right and anterior

c2

Figure 3. With manipulation, the ETT tip can be successfully guided. Images at a1 and a2 show how the ETT initially contacts the right side of the epiglottis; b1 and b2 show how the ETT is turned counterclockwise, which moves the tip back and to the left; and c1 and c2 show how the ETT is turned clockwise, which moves the tip to the right and anterior, thus entering across the vocal cords.

ETT, endotracheal tube Image courtesy of Prodol Meditec.

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Table. Advantages and Disadvantages of Video Laryngoscopes7,14 Advantages

Disadvantages

• Improvement in Cormack-Lehane grade 1-2 view • Improved success of intubation at first attempt in predicted difficult airways compared with conventional laryngoscopy • Reduced requirement for bougie or external laryngeal manipulation • Evidence of utility as a rescue technique in difficult direct laryngoscopy • Other members of the surgical team can see view and so assist • Usefulness as a teaching tool • Advantageous in cervical spine pathology because of reduced need to flex or extend neck, and less force is required, reducing pressure on neck and mucosa • Need for less force to align axes, so reduced risk for dental trauma.

• Increased rates of successful intubation among inexperienced practitioners.

• Many different models, with different characteristics and requirements for positioning blades and optimization maneuvers • Increased rates of successful intubation only in those familiar with the technique • Learning curve to become familiar with the use of different types of equipment • Few data comparing efficacy and side effects of different models • Difficulty passing the ETT despite good view • Time to intubation may be longer • Adequate mouth opening is required • Trauma to mucosa from styleted tubes • Lack of knowledge of all factors making video laryngoscopy difficult, although difficulty known to be associated with altered neck anatomy, previous surgery, and radiotherapy

ETT, endotracheal tube

Conclusion Although VLs can make the management of a difficult airway easier, as with all new equipment, there is a learning curve. It may well be necessary to become proficient with the use of different types of VLs, and although many anesthesiologists find the use of VLs to be intuitive, there is no consensus on how many uses constitute competence; indeed, this may vary from device to device. Despite improvements in the view of

the laryngeal inlet with video laryngoscopy, difficulty passing the ETT into the trachea may result, and the time to successful intubation may be prolonged.14 However, it must be emphasized that experience and competence in the use of VLs are critical to their effectiveness in airway management.

Dr. Hurtado is professor for the course “Management of the Difficult Airway and Handling of the Fiberoptic Bronchoscope,” at University Hospital Getafe and for AnestesiaR.org.

References 1.

Peterson GN, Domino KB, Caplan RA, et al. Management of the difficult airway: a closed claims analysis. Anesthesiology.

2005;103(1):33-39.

8. Behringer EC, Kristensen MS. Evidence for benefit vs novelty in new intubation equipment. Anaesthesia. 2011;66(suppl 2):57-64.

2. Shiga T, Wajima Z, Inoue T, et al. Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology. 2005;103(2):429-437.

9. Martínez Hurtado E. Videolaringoscopios: Manual de Actualización en Dispositivos Opticos (Spanish Edition). ISBN-13: 978-1508874348. ISBN-10: 1508874344.

3. Cantwell R, Clutton-Brock T, Cooper G, et al. Saving mothers’ lives: reviewing maternal deaths to make motherhood safer: 20062008. The eighth report of the confidential enquiries into maternal deaths in the United Kingdom. BJOG. 2011;118(suppl 1):1-203.

10. Aziz MF, Dillman D, Fu R, et al. Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway. Anesthesiology.

2012;116(3):629-636.

4. Aziz MF, Healy D, Kheterpal S, et al. Routine clinical practice effectiveness of the Glidescope in difficult airway management: an analysis of 2,004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology. 2011;114(1):34-41.

11. Larsson A, Dhonneur G. Videolaryngoscopy: towards a new standard method for tracheal intubation in the ICU? Intensive Care Med. 2013;39(12):2220-2222.

5. Jungbauer A, Schumann M, Brunkhorst V, et al. Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients. Br J Anaesth.

2009;102:(4):546-550.

6. Apfelbaum JL, Hagberg CA, Caplan RA, et al. 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. 2013;118(2):251-270.

7.

Healy DW, Maties O, Hovord D, et al. A systematic review of the role of videolaryngoscopy in successful orotracheal intubation.

BMC Anesthesiol. 2012;12:32.

12. Mosier JM, Whitmore SP, Bloom JW, et al. Videolaryngoscopy improves intubation success and reduces esophageal intubations compared to direct laryngoscopy in the medical intensive care unit.

Crit Care. 2013;17(5):R237.

13. Healy DW, Maties O, Hovord D, et al. A systematic review of the role of videolaryngoscopy in successful orotracheal intubation.

BMC Anesthesiol. 2012;12:32.

14. Asai T. Videolaryngoscopes: do they truly have roles in difficult airways? Anesthesiology. 2012;116(3):515-517.

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Unanticipated Difficult Airway Due to a Fibrotic Subglottic Bridge GABRIELA COSTA, MD MARIA JOÃO GOMES, MD MARIANA CUNHA, MD PEDRO VASCONCELOS, MD FERNANDO MOURA, MD Centro Hospitalar do Tâmega e Sousa Department of Anaesthesiology Penafiel, Portugal The authors reported no relevant financial disclosures.

Case Description The patient was a 51-year-old woman undergoing general anesthesia in an ambulatory clinic for an elective tooth extraction. She had a past medical history of chronic alcoholism. The patient was hospitalized in the intensive care unit a few years prior to the surgery due to a spontaneous thalamic hemorrhage and required ventilator support with orotracheal intubation for 48

hours. The patient presented normal relative anatomy, conserved neck mobility, and no stridor. However, right hemiplegia resulting from a stroke made it impossible for her to cooperate for an airway assessment.

The surgery required the patient to be intubated with an orotracheal tube. We administered 0.15 mg fentanyl, 150 mg propofol, and 35 mg rocuronium in the operating room. We did a grade 1 laryngoscopy but intubation failed because of a fibrotic subglottic bridge (Figure). We decided to secure the airway with a laryngeal mask and wake the patient.

Failed intubation consists of endotracheal tube placement failure after multiple attempts. A proper response to these emergency situations involves the use of the laryngeal mask, according to the American Society of Anesthesiologists’ algorithm for management of the difficult airway.1 The patient submitted to laser photocoagulation by rigid bronchoscope with complete removal of the lesion, after which she was able to be successfully intubated and the operation could proceed.

Discussion Preoperative evaluation was incomplete, but difficult intubation was not foreseeable. Pathologic conditions above the glottis may prevent a clear view of the glottic opening, whereas subglottic lesions permit a good view of the vocal cords. Examples of those conditions include tumor, infection, and post-intubation fibrotic stenosis.

According to the literature, there is only 1 case of postintubation fibrotic subglottic bridge.2 The fibrotic subglottic bridge observed in this patient is a rare lesion that should be considered as a cause of unpredictable failed intubation.

References 1.

Figure. View of fibrotic subglottic bridge.

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Apfelbaum JL, Hagberg CA, Caplan RA, et al. 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. 2013;188(2):251-270.

2. Eijó S. “ponte” fibrótica subglótica pós-entubação. onte.” Rev Port Pneumol. 2002;8(6):616-617.

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