HNFO With or Without Helmet NIV for Oxygenation Support in Acute Respiratory Failure Pilot RCT

HNIV will be connected to a ventilator by a conventional closed respiratory circuit. Sessions of HNIV will be delivered with PEEP targeting a minimum 12 hours/day. PEEP will be titrated according to patient comfort, work of breathing, and O2 saturation. Pressure support will be titrated to lowest level tolerated. Between HNIV sessions, patients will be supported with HFNO at the same required FiO2. Starting on study day 3, patients will be screened for discontinuation of HNIV. Once HNIV is stopped, patients will be transitioned to HFNO and then weaned from HFNO as tolerated.

HFNO will be provided. FiO2 will be titrated to achieve a target O2 saturation of 92-97%, and flows will be initiated at 50 litres/minute and titrated as per usual practice for comfort and oxygenation. Once the target O2 saturation is achieved, the FiO2 will be titrated to the minimal value to maintain this target saturation. HFNO will be provided continuously over a minimum of 2 calendar days. Starting on study day 3, patients will be weaned from HFNO as tolerated.