• J-L Hanouz, F Le Gall, J-L Gérard, N Terzi, and H Normand.
• Department of Anaesthesia and Intensive Care Medicine, Caen University Hospital, Caen, France; EA 4650, Caen Normandy University, Unicaen, Caen, France. Electronic address: hanouz-jl@chu-caen.fr.
• Br J Anaesth. 2018 Apr 1; 120 (4): 868-873.

BackgroundDuring preoxygenation, the lack of tight fit between the mask and the patient's face results in inward air leak preventing effective preoxygenation. We hypothesized that non-invasive positive-pressure ventilation and positive end-expiratory pressure (PEEP) could counteract inward air leak.MethodsHealthy volunteers were randomly assigned to preoxygenated through spontaneous breathing without leak (SB), spontaneous breathing with a calibrated air leak (T-shaped piece between the mouth and the breathing system; SB-leak), or non-invasive positive inspiratory pressure ventilation (inspiratory support +6 cm H2O; PEEP +5 cm H2O) with calibrated leak (PPV-leak). The volunteers breathed through a mouthpiece connected to an anaesthesia ventilator. The expired oxygen fraction (FeO2) and air-leak flow (ml s-1) were measured. The primary end point was the proportion of volunteers with FeO2 >90% at 3 min. The secondary end points were FeO2 at 3 min, time to reach FeO2 of 90%, and the inspiratory air-leak flow.ResultsTwenty healthy volunteers were included. The proportion of volunteers with FeO2 >90% at 3 min was 0% in the SB-leak group, 95% in the SB group, and 100% in the PPV-leak group (P<0.001). At 3 min, the mean [standard deviation (sd)] FeO2 was 89 (1)%, 76 (1)%, and 90 (0)% in the SB, SB-leak, and PPV-leak groups, respectively (P<0.001). The mean (sd) inward air leak was 59 (12) ml s-1 in the SB-leak group, but 0 (0) ml s-1 in the PPV-leak group (P<0.001).ConclusionsPreoxygenation through non-invasive positive-pressure ventilation and PEEP provided effective preoxygenation despite an inward air leak.Clinical Trial RegistrationNCT03087825.Copyright © 2017 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

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