Rescuing the obese or burned airway: are conventional training manikins adequate? A simulation study

Background: Percutaneous tracheal access is required in more than 40% of major airway emergencies, and rates of failure are high among anaesthetists. Supraglottic airway management is more likely to fail in patients with obesity or neck pathology. Commercially available manikins may aid training. In this study, we modified a standard 'front of neck' manikin and evaluated anaesthetists' performance of percutaneous tracheal access.

Methods: Two cricothyroidotomy training manikins were modified using sections of belly pork to simulate a morbidly obese patient and an obese patient with neck burns. An unmodified manikin was used to simulate a slim patient. Twenty consultant anaesthetists were asked to manage a 'can't intubate, can't ventilate' scenario involving each of the three manikins. Outcome measures were success using their chosen technique and time to first effective breath.

Results: Success rates using first-choice equipment were: 'slim' manikin 100%, 'morbidly obese' manikin 60%, and 'burned obese' manikin 77%. All attempts on the 'slim' manikin succeeded within 240 s, the majority within 120 s. In attempts on the 'morbidly obese' manikin, 60% succeeded within 240 s and 20% required more than 720 s. All attempts on the 'burned obese' manikin succeeded within 180 s.

Conclusions: Significantly greater technical difficulty was experienced with our 'morbidly obese' manikin compared with the unmodified manikin. Failure rates and times to completion were considerably more consistent with real-life reports. Modifying a standard manikin to simulate an obese patient is likely to better prepare anaesthetists for this challenging situation. Development of a commercial manikin with such properties would be of value.