Airway management during spaceflight - A comparison of four airway devicesin simulated microgravity

Background The authors compared airway management in normogravity and simul ated microgravity with and without restraints for laryngoscope-guided trach eal intubation, the cuffed oropharyngeal airway, the standard laryngeal mas k airway, and the intubating laryngeal mask airway. Methods: Four trained anesthesiologist-divers participated in the study. Si mulated microgravity during spaceflight was obtained using a submerged, ful l-scale model of the International Space Station Life Support Module and ne utrally buoyant equipment and personnel. Customized, full-torso manikins we re used for performing airway management. Each anesthesiologist-diver attem pted airway management on 10 occasions with each device in three experiment al conditions: (1) with the manikin at the poolside (poolside); (2) with th e submerged manikin floating free (free-floating); and (3) with the submerg ed manikin fixed to the floor using a restraint (restrained). Airway manage ment failure was defined as failed insertion after three attempts or inadeq uate device placement after insertion. Results: For the laryngoscope-guided tracheal intubation, airway 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 oropharynge al airway (poolside, 10%; free-floating, 15%; restrained, 15%), laryngeal m ask airway (poolside, 0%; free-floating, 3%; restrained, 0%), and intubatin g laryngeal mask airway (poolside, 5%; free-floating, 5%; restrained, 10%), Airway management failure for the laryngoscope-guided tracheal intubation was usually caused by failed insertion (> 90%), and for the cuffed orophary ngeal 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 t racheal intubation in microgravity is appropriate. Extratracheal airway dev ices may be useful when restraints cannot be applied or intubation is diffi cult.