Fig. 1.
Drawing of the high flow circuit used to apply 50% oxygenated humidified air at adjustable pressures. Sevoflurane was added by the standard anesthesia workstation using a vaporizer when required. The inspiratory limb of the anesthesia workstation connected to an adjustable positive end-expiratory pressure (PEEP) valve and allowed the insufflation of humidified air before connecting the occlusion valve to the pneumotachograph. The expiratory limb of the anesthesia workstation connected to a second PEEP valve before linking to the pneumotachograph. The nasal mask offered ports that had been modified to connect to the mask and epiglottic pressure sensors. If necessary, the mouth was sealed with a tape to eliminate any leakage of air.