Airway Management during Spaceflight

Abstract

Background: The authors compared airway management in normogravity and simulated microgravity with and without restraints for laryngoscope-guided tracheal intubation, the cuffed oropharyngeal airway, the standard laryngeal mask air- way, and the intubating laryngeal mask airway. Methods: Four trained anesthesiologist–divers participated in the study. Simulated microgravity during spaceflight was ob- tained using a submerged, full-scale model of the International Space Station Life Support Module and neutrally buoyant equip- ment and personnel. Customized, full-torso manikins were used for performing airway management. Each anesthesiolo- gist–diver attempted airway management on 10 occasions with each device in three experimental conditions: (1) with the man- ikin at the poolside (poolside); (2) with the submerged manikin floating free (free-floating); and (3) with the submerged mani- kin fixed to the floor using a restraint (restrained). Airway management failure was defined as failed insertion after three attempts or inadequate device placement after insertion. Results: For the laryngoscope-guided tracheal intubation, air- way management failure occurred more frequently in the free- floating (85%) condition than the restrained (8%) and poolside (0%) conditions (both, P < 0.001). Airway management failure was similar among conditions for the cuffed oropharyngeal airway (poolside, 10%; free-floating, 15%; restrained, 15%), la- ryngeal mask airway (poolside, 0%; free-floating, 3%; re- strained, 0%), and intubating laryngeal mask airway (poolside, 5%; free-floating, 5%; restrained, 10%). Airway management failure for the laryngoscope-guided tracheal intubation was usu- ally caused by failed insertion (> 90%), and for the cuffed oropharyngeal airway, laryngeal mask airway, and intubating laryngeal mask airway, it was always a result of inadequate placement. Conclusion: The emphasis placed on the use of restraints for conventional tracheal intubation in microgravity is appropri- ate. Extratracheal airway devices may be useful when restraints cannot be applied or intubation is difficult.