Impact of combined non-invasive support strategies use during acute respiratory failure due to COVID-19.

Objectives: To evaluate the impact of combined non-invasive support strategies in critically ill COVID-19 patients [high-flow nasal cannula (HFNC), non-invasive ventilation (NIV) or both]. Method(s): Prospective observational multicenter study in 73 Spanish ICU with data obtained from the SEMICYUC registry. All confirmed COVID-19 patients admitted due to respiratory failure were included. They were classified according to the ventilatory strategy used on admission and subsequently according to success, failure, or strategy change. Demographic data, comorbidities, severity at admission, respiratory, biomarkers, failure, length of stay and mortality were evaluated. Result(s): We analyzed 3,889 patients, 33% receiving HFNC, and 11% NIV at ICU admission. NIV group compared to HFNC were more severely ill with more shock on admission. When NIV was received as a first-choice higher failure rates and mortality were shown vs HFNC (68% vs 61%, p=0.016 and 27% vs 20%, p=0.003). Among patients who initially received HFNC, 57% failed and 7.4% switched to NIV, with no change in mortality. Among patients who were switched to NIV, 66% failed presenting a higher mortality trend than the intubated patients after the HFNC starting (40% vs 30%, p=0.098). Among patients who initially received NIV, 60% failed and 20% switched to HFNC. Patients in whom NIV was switched to HFNC, had lower mortality than patients who initially failed (18% vs 40%, p<0.001). Among patients who were switched to HFNC, 43% failed, presenting the same mortality as the intubated patients after the NIV starting (38% vs 38%, p=0.934). Conclusion(s): Patients receiving NIV at admission have worse outcomes than those receiving HFNC. Changing the strategy in patients who received HFNC as a first choice without success can worsen the prognosis.