A difficult airway is defined by the American Society of Anesthesiologists (ASA) as “the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with face mask ventilation of the upper airway, difficulty with tracheal intubation, or both.”¹ A mismanaged difficult airway is often an immediate threat to the patient’s life. Therefore, it is essential for all anesthesiologists to be experts in difficult airway management (DAM). Although analysis of the ASA closed claim database suggests that implementation of the ASA DAM algorithm over the past two decades has reduced the number of failed difficult airways during induction of anesthesia,2 outcomes in simulated DAM indicate that a significant percentage of currently practicing anesthesiologists are poor managers of the difficult airway, with up to a third of simulated emergent pathway airways ending in simulated death.³,⁴ There are two factors that probably contribute to this lack of expertise. First, the ACGME requirements for training in DAM during residency are remarkably nonspecific, 5 and there are understandably a wide variety of approaches to teaching management of the difficult airway. Second, DAM is not an everyday occurrence. It has been estimated that encountering a difficult airway is a relatively rare event. In one particular study, there were 100 out of 11,257 unanticipated difficult intubations.⁶ Difficult ventilation, however, seemed even more rare with 6 of 11,257 being difficult but 0 of 11,257 being classified as impossible ventilations.⁶ It may be difficult for many anesthesiologists to gain enough experience to become and remain expert difficult airway managers based solely on their residency training and clinical experience. Thus, it is imperative for the anesthesiologist to receive additional training in DAM beyond everyday clinical experience.

Simulation provides experience to the learner in a more controlled and structured environment than is possible in the clinical arena. Simulation of the difficult airway is in many respects the most ideal method to learn DAM. Advantages of simulation as opposed to in vivo training include (1) improved safety to the patient, (2) the ability for increased exposure to unlikely or rare scenarios, (3) the ability to manipulate and customize those scenarios, and (4) decreased incidence of malpractice claims.⁷

There are several concerns that must be addressed before any simulation program can be accepted as a suitable tool for teaching DAM and measuring competence in DAM. The chief concern is validation, that is, does the simulation program truly measure what it purports to measure? Can the simulation environment reproduce the events normally encountered in the clinical arena? Do the tools used clinically function in the expected way in the simulation environment? Does the simulation program define competence in a way that most experts in the field would endorse? Can it reliably discriminate between an expert and a novice? Is the measurement of competence in a given subject reproducible over repeated measures? How long does the effect of the training and measurement last (ie, retention)? These concepts are vital in assessing the effectiveness of any educational program, but particularly so in the field of simulation which has been plagued in the past by a relative lack of effectively validated studies.⁸

Fortunately, validity has been shown to be high in regard to many aspects of DAM simulation. The primary factor responsible for this is the existence of the ASA Difficult Airway Algorithm, which provides a peer-reviewed gold standard for the management of the difficult airway. It has been shown that DAM simulation courses seem to have high correlation with clinical scenarios.⁹,¹⁰ This is probably because most scenarios are based on events that have occurred in the clinical realm. It has also been shown that there is high validity of the actual specific airway techniques for the Laerdal Simman.¹¹ The validity of DAM simulation is not confined just to anesthesiology but also appears to extend to other medical specialties as well as to prehospital providers.¹²,¹³ Finally, it appears that various DAM courses that are designed with a structured curriculum produce similar results.¹²,¹³

Reliability has also been shown to be very high for DAM simulation. There has been significant intratrainee reproducibility within a DAM simulation course.¹⁴ DAM simulation can reliably discriminate between experienced, competent airway managers and novices who would not be expected to be competent.⁹

The question of how long DAM skills taught using simulation are retained remains unanswered and will require additional research. Early data suggested that DAM skills taught via simulation were reasonably well maintained at 1 to 3 years after initial training.¹⁵ Other recent data, however, showed that it may be necessary to repeat DAM simulation every 6 months or less.¹⁶ This data showed that skills acquired for cannot intubate/cannot ventilate were retained for approximately 6 to 8 months, but the skills acquired for cannot intubate were only retained for 6 to 8 weeks.¹⁶ Length of retention is likely related to how often the anesthesiologist encounters the difficult airway in daily clinical practice.

As simulation has become more widely accepted as a vital tool for teaching and assessing DAM, more of the most prestigious anesthesiology residencies are implementing structured simulation courses in DAM for residency training. In addition, the American Board of Anesthesiology has recognized DAM simulation as one of the core areas eligible for its Maintenance of Certification in Anesthesiology program and is working with the ASA Simulation Network to increase opportunities for practicing anesthesiologists to obtain additional simulation training in DAM.¹⁷

At UPMC, the Winter Institute for Simulation, Education, and Research (WISER) plays a vital role in training residents, fellows, and attending physicians in DAM. There are three courses that share a basic curriculum and format but in which the specific simulation scenarios are tailored to the specialties in which DAM is crucial. These specialties included are anesthesiology, critical care medicine, and emergency medicine. The courses taught to anesthesia and critical care medicine (CCM) providers are very similar, whereas the DAM course taught to emergency medicine physicians focuses on how to quickly assess an airway and how the difficult airway applies to rapid sequence intubation. All courses are structured around the ASA Difficult Airway Algorithm. Our residency has required that all anesthesiology residents attend the Anesthesiology DAM course each year during their CA-1 through CA-3 years, for more than a decade. All anesthesiology faculty at UPMC must complete the Anesthesiology DAM simulation prior to being granted medical staff privileges in anesthesiology.