Table 2.

General Indications and Contraindications of HFNCOT

Indications	Contraindications
Hypoxemic acute respiratory failure: PaO2/FiO2 < 300 mmHg (40 kPa), and respiratory rate > 25 breaths/min, despite conventional oxygen therapy (with flow > 8 L/min)	Hypercapnia, PaCO2 ≥ 45 mmHg (6 kPa), hemodynamic instability, severe failure of ≥ 2 organs, Glasgow Coma Scale ≤ 13, urgent requirement of endotracheal intubation, non-cooperating patients, facial abnormalities preventing the use of nasal cannula, and recent facial or nasal surgeries