Methods
MAY, SECONDARY
This report comprises a secondary publication based on additional data that were collected during a single-center randomized controlled trial undertaken between September 2018 and May 2019 at the Royal Brisbane and Women’s Hospital [All participants were monitored according to local standards, with the addition of invasive radial arterial catheters. Participants were randomized to Group T, in which they were administered high flow nasal oxygen using Optiflow THRIVE™ at 70 L/min, humidified using the Fisher & Paykel 950 humidifier, providing 70% relative humidity (oxygen concentration delivered at 100%); or to Group N, in which they were administered standard nasal prongs at 4 L/min (Salter Labs, Arvin, CA, USA). In both groups, pre-oxygenation occurred in the ramped position and with FiOInduction medications consisted of an opioid, propofol, and rocuronium with dosing at the discretion of the anesthetist. Anesthesia maintenance was achieved using propofol target controlled infusion. The patients were bag-mask ventilated to achieve an end-tidal oxygen fraction > 0.9. At this point, nasal oxygenation was applied according to group allocation and airway patency maintained using an oropharyngeal airway and two-handed airway maneuvers (chin lift, head tilt, jaw thrust).Clinical observations and sampling occurred while the participants were anesthetized and apneic. TcCOThe sample size was a convenience sample of 42, determined according to the primary outcome of the original study [