My first response on being asked to write an article on the progression of emergency airway management since ACEP was founded was that I am not that old. But actually, my career in emergency care started in 1980 as an EMT. For the thousands of residents now training in our specialty, and anyone who started after the 1980s, it’s hard to imagine how emergency medicine was practiced in the ’60s and ’70s. The pioneers of our specialty created their practice out of necessity, a consequence of emergency care being neglected by the established specialties. It took guts, especially in academic environments with political turf wars, for self-taught emergency physicians to start staking out responsibility for critical, time-sensitive procedures, including airway management.
Explore This IssueACEP Now: Vol 37 – No 08 – August 2018
Improved Airway Devices
In hindsight, the late ’70s and ’80s were a major transitional time in airway management. The start of the decade saw the invention of the laryngeal mask airway (LMA) as well as the esophageal tracheal Combitube. These devices were a marked improvement over both mask ventilation and the EMS airway at the time, the esophageal obturator airway (EOA). The EOA was a co-esophageal blocker married to a face mask, but it still had all the deficiencies of mask ventilation. It was a good vomit directional device, but was not a significant improvement in ventilation or oxygenation over mask ventilation.
The Combitube, invented by Michael Frass, was a step forward in that it combined a pharyngeal balloon with an esophageal balloon. The seal of the airway was now within the hypopharynx. The Combitube became the default airway solution for EMS agencies, as it was easy to insert and very stable once the pharyngeal balloon was inflated. It isolated the larynx and trachea from the esophagus (and stomach contents). The Combitube has been since largely replaced by a better designed two-balloon blocking device, the King laryngeal tube (King LT).
Anesthesiology embraced an alternative means of ventilation just as the Combitube was coming into vogue with EMS. Archie Brain, MD, an anesthetist from Britain, created an intra-oral sealing device he called the LMA. This small triangular mask slid along the hard palate, down and behind the tongue, with the tip of the triangular mask wedged into the upper esophagus. Although not a complete blocker of the esophagus, the mask created an effective ventilatory seal in the hypopharynx, over the larynx. Dr. Brain’s original device and many LMA-type devices still to this day use inflatable cuffs, but it turns out that the sealing of the airway is due to the collapse of soft tissue (created by gravity and sedation, usually propofol) down onto the mask. It would take almost 20 years for this to be widely recognized; newer LMA-type devices have either very-low-volume cuffs (the i-gel, Cook air-Q, Ambu Aura, LMA Supreme) or no cuff at all. The latest generation of these devices adds gastric decompression ports, further improving safety.
The Combitube and King LT along with the LMA and its successors have revolutionized prehospital airway management and completely changed anesthetic delivery for nonemergent cases. The LMA is now used in the vast majority of elective surgical cases worldwide. These devices have also provided options for rescue ventilation in emergency departments. Prior to these devices, if intubation failed, the only option was mask ventilation or cricothyrotomy. Unfortunately, difficult direct laryngoscopy and difficult mask ventilation can often occur in the same patients. After the invention of effective rescue ventilation devices, failure to place a tube didn’t necessitate an immediate surgical airway. It is reassuring to know that obesity in and of itself is not a problem for effective supraglottic airway use (assuming the patient is placed in head-elevated positioning). The LMA and Combitube were centrally featured in the first Difficult Airway Algorithm, created by the American Society of Anesthesiology in 2004. Along with video laryngoscopes, airway management options have expanded dramatically in the last two decades.
End-Tidal CO2 Detection and Use of Neuromuscular Blockers
Another seminal change in airway management, also from the 1980s, was the widespread adoption of end-tidal CO2 detection for the confirmation of tracheal tube placement and effective ventilation. Prior to this, unrecognized esophageal intubation was a major risk in elective surgical cases and very common in emergency airways. Capnography or colorimetric devices now confirm all intubations in all settings, in or out of the hospital. Academic emergency physicians identified the dangers of unrecognized esophageal intubation and changed the standard of care.
Emergency physicians (led by Ron Walls, MD, and Michael Murphy, MD, in the 1980s) were largely responsible for the widespread adoption of muscle relaxants being used in emergency airways. That coupled with end-tidal CO2 detection and rescue ventilation devices led to a sharp decrease in the number of cricothyrotomies performed in emergency departments. According to Chang et al, at New York’s Bellevue Hospital, cricothyrotomies declined from 1.8 percent in trauma patients to less than 0.2 percent after the initiation of the emergency medicine residency program.1
Prior to the universal establishment of emergency medicine residency programs at academic centers, it was a great challenge for emergency medicine practitioners to acquire formal training in airway management. It’s noteworthy that The Difficult Airway Course (created by Dr. Walls, Dr. Murphy, Robert Luten, MD, and Robert Schneider, MD) has had an incredible impact on disseminating airway education to tens of thousands of emergency physicians. The transition from anesthesia to emergency physicians being the primary airway providers (in trauma and all ED patients) coincided with the growing respect and power of emergency medicine that developed within academic centers. Having been a resident during emergency medicine’s “adolescence,” it is inspirational for me to see emergency physicians as senior administrators of major academic centers and medical schools.
Rapid sequence intubation in emergency airways, end-tidal CO2 detection for verification of tube placement, “O’s up the nose,” apneic oxygenation, and video laryngoscopy—all the major components of current airway practices—have been pioneered, researched, and validated by emergency physicians.
It is not coincidental, but rather something the pioneers of our specialty intended, that the academic advancement of emergency medicine would improve patient care. This can certainly be seen in myocardial infarction, stroke, and sepsis. Although I’m biased, I am especially proud of emergency medicine’s role in improving emergency airway management.
When I chose emergency medicine as a specialty, I was told by my medical school dean that we were “just triage doctors.” I now see growing validation of emergency medicine’s approach to airway management as well as visible evidence that our contributions have been leading the way.
Check out the following five articles—among my favorites by emergency physicians—and give a pat on the back to the authors whose work has improved your practice and boosted patient safety:
- Driver BE, Prekker ME, Klein LK, et al. Effect of use of a bougie vs endotracheal tube and stylet on first-attempt intubation success among patients with difficult airways undergoing emergency intubation: a randomized clinical trial. JAMA. 2018;319(21):2179-2189. (recommended by Dr. Levitan)
- Kovacs G, Sowers N. Airway management in trauma. Emerg Med Clin North Am. 2018;36(1):61-84. (recommended by Dr. Kovacs)
- Sakles JC, Chiu S, Mosier J, et al. The importance of first pass success when performing orotracheal intubation in the emergency department. Acad Emerg Med. 2013;20(1):71-78. (recommended by Dr. Sakles)
- Walls RM, Brown CA 3rd, Bair AE, et al. NEAR II Investigators. emergency airway management: a multi-center report of 8937 emergency department intubations. J Emerg Med. 2011;41(4):347-354. (recommended by Dr. Walls)
- Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012;59(3):165-175. (recommended by Dr. Levitan)
- Chang RS, Hamilton RJ, Carter WA. Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training. Acad Emerg Med. 1998;5(3):247-251.