Abstract:
Study Objective: To investigate the efficacy of preoxygenation by eight deep breaths in 60 seconds with the Mapleson A (Magill) system, the circle anesthesia system, or the Mapleson D system at an oxygen flow of 5 L-min or 10 L-min. Design: Randomized, clinical study. Setting: Operating room of a university hospital. Subjects: 10 healthy volunteers. Interventions: Volunteers underwent 6 preoxygenation trials consisting of 8 deep breaths in 60 seconds using the Mapleson A, Mapleson D, and the circle anesthesia systems at an oxygen flow of 5 L-min and 10 L-min. Measurements: Fractional end-tidal oxygen concentration (FETO2) was measured at 15-second intervals during preoxygenation. Results: At an oxygen flow of 10 L-min, mean FETO2 values at 60 seconds of preoxygenation were comparable among the Mapleson A, Mapleson D, and the circle anesthesia systems (87 ± 2.1percent, 87 ± 1.6percent, 87 ± 1.6percent, respectively). Using an oxygen flow of 5 L-min, mean FETO2 values at 60 seconds were similar among the Mapleson A, Mapleson D, and circle anesthesia systems (74 ± 4.1percent, 75 ± 2.6percent, 74 ± 4.4percent, respectively); however, they were significantly lower than the corresponding values achieved at an oxygen flow of 10 L-min. Conclusions: The 8-deep-breaths in 60 seconds technique at an oxygen flow of 10 L-min can achieve adequate preoxygenation with the Mapleson A (Magill), Mapleson D, and circle anesthesia systems. Suboptimal preoxygenation is obtained with the three systems when the oxygen flow used is 5 L-min. © 2009 Elsevier Inc. All rights reserved.