Figure 1.

Flowchart for the treatment of type 1 respiratory failure. SpO₂ = peripheral oxygen saturation, FiO₂ = fraction of inspired oxygen, PaCO₂ = partial pressure of carbon dioxide in arterial blood, cCPAP = continuous (i.e., nonintermittent) continuous positive airway pressure, HFNC = high-flow nasal cannula oxygen therapy, IMV = invasive mechanical ventilation, BiPAP = bilevel positive airway pressure, COPD = chronic obstructive pulmonary disease, COVID-19 = coronavirus disease 2019. Adapted from Nielsen Jeschke K. et al. 2020 [25].