Physiological Effects of Non-invasive Mechanical Ventilation Versus High-flow Nasal Cannula in Critically Ill Patients At High Risk of Extubation Failure

Non-invasive ventilation will be provided through a mechanical ventilator (Carina, Dräger) through a facial interface (Fitlife Respironics, Philips). A PEEP level between 5 and 10 cmH2O, minimal pressure-support level of 5 cm H2O targeting a tidal volume around 6 to 8 ml/kg and at the same FiO2 applied during the spontaneous breathing trial.

High flow nasal cannula will be provided through a commercial device (AIRVO2 + Optiflow nasal cannula, Fisher \& Paykel), at 50 LPM and at the same FiO2 applied during the spontaneous breathing trial.