Prediction of Extubation Failure in COVID-19.

Background: [Formula: see text] may be a reliable noninvasive alternative to the [Formula: see text] index. Furthermore, the ROX index (ie, the ratio of [Formula: see text] to breathing frequency) has been validated to predict high-flow nasal cannula failure in subjects under spontaneous breathing. However, these indices have not been tested in subjects with COVID-19 receiving invasive mechanical ventilation.