The focus of this viva is Evidence Based Medicine.

Please read this modified abstract.

High-Flow Nasal Oxygen vs Noninvasive Positive Airway Pressure in Hypoxemic Patients After Cardiothoracic Surgery

OBJECTIVE: To determine whether high-flow nasal oxygen therapy (HFNO2) was not inferior to BiPAP for preventing or resolving acute respiratory failure after cardiothoracic surgery.

DESIGN: Multicenter, randomized, non-inferiority trial

PARTICIPANTS: 830 of 3217 eligible patients who had undergone cardiothoracic surgery with acute respiratory failure (failure of a spontaneous breathing trial or successful breathing trial but failed extubation) or were deemed at risk for respiratory failure after extubation due to preexisting risk factors.

INTERVENTIONS: Patients were randomly assigned to receive HFNO2 delivered continuously (flow 50 L/min, FiO2 0.5) or BiPAP delivered with a full-face mask for at least 4 hours per day (PSV 8 cm H2O, PEEP 4 cm H2O, FiO2 0.5)

HFNO2 was delivered continuously through a nasal cannula. The initial flow rate was 50 L/min and the initial FiO2 was 0.5, adjusted to maintain SpO2 at 92% to 98%. Bilevel positive airway pressure (BiPAP) was delivered with a full-face mask and either a specific BiPAP ventilator or an ICU ventilator in pressure-support mode with added PEEP.

What are the strengths and weaknesses of the design of this study?

Disclaimer: the viva stem above may be an original CICM stem, acquired from their publicly available past papers. Or, perhaps it is a slightly altered version of the original CICM stem. Or, it is a completely original viva stem, concocted by the monstrously amoral author of Deranged Physiology for nothing more than his own personal amusement. In either case, because the college do not make the main viva text or marking criteria available, almost everything here has been confabulated. It might sound like a plausible viva and it could be used for the purpose of practice, but all should be aware that it does not represent the "true" canonical CICM viva station.