Predicting the successful application of high-flow nasal oxygen cannula in patients with COVID-19 respiratory failure: a retrospective analysis.

High flow nasal cannulas (HFNCs) were widely used in patients with COVID-19 infection related hypoxemic respiratory failure. However, there were concerns about its failure and related delayed intubation may be associated with a higher mortality rate. This retrospective study revealed patients with higher baseline disease severity and higher VICE scores may be treated with primary invasive mechanical ventilation. On the contrary, if their baseline VICE score is low and ROX index is high, HFNCs treatment might be safely applied initially. The trends of serial ROX index values during HFNC use could be a reliable periscope to predict the HFNC therapy outcome, therefore avoided delayed intubation.