1. Non-invasive positive-pressure ventilation with positive end-expiratory pressure counteracts inward air leaks during preoxygenation: a randomised crossover controlled study in healthy volunteers 
J.-L. Hanouz, F. Le Gall, J.-L. Gérard, N. Terzi, H. Normand 
British Journal of Anaesthesia 
Volume 120, Issue 4, Pages (April 2018)
DOI: /j.bja
Copyright © 2017 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
Part of the breathing circuit showing the T-shaped piece used to calibrate air leak and the pneumotachograph sensor.
British Journal of Anaesthesia  , DOI: ( /j.bja )
Copyright © 2017 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
Time course of expired oxygen fraction between groups. PPV-leak, non-invasive PPV group with a calibrated air leak; SB, spontaneous-breathing group without air leak; SB-leak, spontaneous-breathing group with a calibrated air leak.
British Journal of Anaesthesia  , DOI: ( /j.bja )
Copyright © 2017 British Journal of Anaesthesia Terms and Conditions

4. Fig 3
Kaplan–Meier plot for the probability that expired oxygen fraction reached 90%. PPV-leak, non-invasive PPV group with a calibrated air leak; SB, spontaneous-breathing group without air leak; SB-leak, spontaneous-breathing group with a calibrated air leak.
British Journal of Anaesthesia  , DOI: ( /j.bja )
Copyright © 2017 British Journal of Anaesthesia Terms and Conditions