UMOX™: A New Device for Preoxygenation

Background - Preoxygenation is performed before general anesthesia to increase the oxygen reserves of the body and prolong the safe period of apnea without hypoxia. However, it is often impossible to obtain a perfect face mask fit, and optimal end-tidal fractional oxygen concentration (EtO2) are not attained. The investigators designed a new oropharyngeal preoxygenation device, UMOX™, to avoid leaks during preoxygenation. In this study, the investigators compared the efficacy of UMOX™ with that of a conventional face mask. Methods - In 50 healthy volunteers breathing 100% oxygen from a circle absorber system for a 5 minute-period, the investigators compared preoxygenation using the 1) a conventional mask; 2) UMOX™ without any instruction; 3) UMOX™ with instruction on mouth breathing; and 4) UMOX™ with a nose clip, in random order. Each subject underwent all steps with a 10-minute rest period of room air breathing between each step. Inspired and end-tidal respiratory gases were measured every 10 seconds. EtO2 variation was analyzed using Anova.