Jan 192015

Image: Airwaycam

Endotracheal intubation is a routine but high-stakes maneuver, performed uneventfully thousands of times daily throughout the developed world. In the U.S., elective (routine) intubation is almost exclusively the domain of anesthesiologists, who become masters of the technique through thousands of iterations throughout training and their careers. The vast majority of these intubations take place in the operating theater, a relatively controlled, stable setting.

But in the emergency department, intensive care unit and medical wards, endotracheal intubation shows its dark side. When performed in rapidly deteriorating patients who are obese, combative, hypoxemic, hypotensive, with preexisting cardiopulmonary disease (or all of the above), intubation often becomes difficult and dangerous. As the difficulty of intubation and the severity of illness increase, the margin for error shrinks, and the risks to the patient rise exponentially. Outside the O.R., intubation is rarely “routine."

These more-risky settings include >90% of the intubations performed by intensivists. Yet surprisingly, no standardized training curriculum exists for teaching of this crucial skill to critical care fellows. Program directors and fellows in pulmonary and critical care have reported serious concerns about the state of training of urgent/emergency intubation:

  • More than 40% of fellowship programs reported having no designated airway rotation;
  • Less than 2/3 of program directors felt they had adequate staff to train fellows in emergency intubation;
  • One third had no protocol in place for emergency intubations;
  • 40% of fellows predicted that at graduation, they would not be proficient in emergency intubation;
  • Most program directors reported minimal, if any structured training on emergency airway techniques including laryngeal mask airways (LMA), stylets (bougies), or fiberoptic intubation.

Program directors also reported a wide variation in the perceived number of intubations (emergency or routine) required for competence. They expressed a median number of emergency intubations of 25 to achieve competence. But true proficiency may require much more practice. One study showed that among anesthesiologists in training, after 80 intubations in varying conditions, 18% of residents still required assistance.

Intubation with Video Laryngoscopy (GlideScope®) vs. Direct Laryngoscopy

Video laryngoscopes (e.g., GlideScope®) have become standard in many O.R.s and ICUs, based on local preferences, anecdotal experience and some observational trial evidence suggesting video laryngoscopy reduced esophageal intubations and increased first-pass success in the emergency department and ICU, especially for patients with difficult airways. Notably, many of these intubations were done by critical care fellows or EM residents.

Video laryngoscopy-guided intubation (GlideScope)

Video laryngoscopy-guided intubation (image: Verathon)

A 2012 meta-analysis concluded that video laryngoscopy improves visualization of the glottis and may improve first-pass intubation success by non-experts, but does not improve experts' performance compared to direct laryngoscopy.

Michael Silverberg et al report the first randomized trial comparing direct laryngoscopy (DL) to video laryngoscopy (VL) for urgent intubation by physicians in training. They randomized 117 patients at Beth Israel ICUs requiring urgent intubation to undergo either DL or VL as the first method by a pulmonary / critical care fellow (year 1, 2, or 3). Fellows all had undergone airway training, including intubation simulations.

Fellows successfully intubated all but 2 patients (whom their attendings then intubated). But video laryngoscopy was demonstrably superior: fellows succeeded on the first pass 74% of the time using the GlideScope, vs. 40% using direct laryngoscopy. There were no cases of intubation failure with the GlideScope. In several patients, direct laryngoscopy failed and the GlideScope was used successfully in all these cases (82% on the first pass after initial failure using DL).

Critical Care Airway Training: Where Do We Go From Here?

Rising expectations for quality, safety, and avoidance of liability have led many U.S. teaching hospitals to not-so-gently nudge critical care fellows aside in favor of an "anesthesiology first" approach to all intubations. While arguably good for patients, since anesthesiologists are better than intensivists at intubation, many critical care fellows have consistently reported feeling less proficient in intubations as a result.

Based on the available evidence, video laryngoscopy is probably superior to direct laryngoscopy for intubation by inexperienced operators. Training programs have reported increasing use of GlideScopes, but reliance on GlideScope technology in training and practice could result in inadequate proficiency with direct laryngoscopy for future intensivists.

In a review of thousands of intubations, though, the GlideScope also bailed out experienced anesthesiologists after failed direct laryngoscopy 94% of the time, just like the neophytes in this study. Some leaders might happily accept a generation of video-dependent intensivists in the interest of better outcomes, as has been argued for the standard use of ultrasound guidance in central line placement.

Considering the above survey results and the underlying trends, are future critical care fellows really going to get enough experience in direct and video laryngoscopy to achieve genuine proficiency in both? If this is considered an important goal, an "always try with DL first" approach might be needed during fellowship, followed by video laryngoscopy for failures.

Speaking of airway training: despite the bluff and bravado by professionals whose pride may partly depend on denying it, it's a simple truth that anesthesiologists are always going to be the best at the airway. There's no shame in it: they've just had the most practice. They've also been working for decades on the use of checklists, protocols and and systems engineering to create a no-failure environment for intubations.

Ensuring future generations of U.S. intensivists are proficient at airway management should start with a humble and public admission by non-anesthesiologists of this inevitable disparity in skills, followed by a serious invitation for anesthesiologists to assume co-ownership of (and responsibility for) airway training for all critical care fellows.

Read more:

Silverberg MJ et al. Comparison of Video Laryngoscopy Versus Direct Laryngoscopy During Urgent Endotracheal Intubation: A Randomized Controlled Trial. Crit Care Med. 2014 Dec 4.

Astha Chichra et al. Barriers to Training Pulmonary and Critical Care Fellows in Emergency Endotracheal Intubation Across the United States. Chest. 2011;140(4_MeetingAbstracts):1036A.

Joffee AM et al. A national survey of airway management training in United States internal medicine-based critical care fellowship programs. Respir Care. 2012 Jul;57(7):1084-8.

Aziz MF 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 Jan;114(1):34-41.

Konrad C et al. Learning manual skills in anesthesiology: Is there a recommended number of cases for anesthetic procedures? Anesth Analg. 1998 Mar;86(3):635-9.

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Should video-guided intubation be standard training in critical care? (And should anesthesiologists teach it?)