Impact of HFNC application on mortality and intensive care length of stay in acute respiratory failure secondary to COVID-19 pneumonia.

This was a retrospective cohort study, not a randomised trial, so it cannot establish that high-flow oxygen caused the lower mortality or intubation rates. Patients were allocated by device availability and order of application, not by random assignment. The sample was small: 43 patients total, 24 in the high-flow group and 19 in the conventional oxygen group. Baseline imbalance: comorbidity was higher in the conventional oxygen group (17 of 19 versus 12 of 24), hypertension was higher (12 of 19 versus 6 of 24), and mean age was higher (69,5 versus 63,3 years). Most patients had P/F ratios between 100 and 200, so results may not apply to mild or severe respiratory failure. Self-prone positioning was excluded, and patients who could not prone due to refusal or noncompliance were included, limiting comparison with usual care. All patients received prophylactic anticoagulant therapy and guideline-based fluid management, and many could receive rescue non-invasive or invasive ventilation, so the effect of high-flow oxygen alone cannot be separated.

No specific grant was received, and the authors declare no conflicts of interest.

Do not conclude that high-flow nasal oxygen reduces mortality or intubation compared with mask oxygen. The study was retrospective, treatment was chosen by device availability rather than randomisation, the mask group had more comorbidities and hypertension, and all patients also received prophylactic anticoagulation and guideline-based fluid management.