Table 1.

When high flow nasal oxygen can and cannot be used

HFNO can be used with some benefits	Hypoxemic acute respiratory failure without extrapulmonary organ failure
	After extubation in low risk patients
	Patients with do-not-intubate orders
HFNO can be used without clear benefits	After extubation following cardiothoracic surgery
	With flexible bronchoscopy
HFNO cannot be used	Hypoxemic ARF with criteria for intubation
	Hypoxemic ARF with extrapulmonary organ failure
Settings where HFNO use requires further clarification	Acute exacerbation of COPD
	Immunocompromised patients with ARF
	Preoxygenation for the intubation of hypoxemic patients
	Post extubation in surgical patients

HFNO - high flow nasal oxygen; ARF - acute respiratory failure; COPD - chronic obstructive pulmonary disease.