No abstract

Background: The efficacy and safety of high-flow nasal cannula (HFNC) oxygen therapy in severe respiratory failure, especially induced by COVID-19, has not been fully elucidated. We aimed to examine the usefulness of HFNC compared to invasive mechanical ventilation (IMV) as initial respiratory management for severe COVID-19-induced respiratory failure.Methods: In this retrospective observational study, we enrolled and categorized the patients with COVID-19-induced severe respiratory failure who were intolerant of conventional oxygen therapy into two groups: 1) patients who initially received HFNC (HFNC group) and 2) patients who initially underwent IMV (IMV group). The primary outcome was in-hospital mortality. The secondary outcomes were ventilator-free days within 28 days, intensive care unit (ICU)-free days within 28 days, and respiratory failure days defined as the length from day 1 to achieving successful weaning from both HFNC and IMV.Results: We analyzed 182 patients (HFNC group, n=81; IMV group, n=101). There was no difference in in-hospital mortality between the two groups (19% in the HFNC group vs. 25% in the IMV group, p=0.37). Initial use of HFNC was not associated with mortality in the univariate analysis (OR, 0.69; CI, 0.34–1.42; p=0.31) and inverse probability of treatment weighting analysis using propensity scoring (OR, 1.01; CI, 0.37–2.77; p=0.984). Ventilator-free days within 28 days were significantly longer in the HFNC group than those in the IMV group (median, 22 days [interquartile range (IQR), 2–28 days] vs. median, 14 days [IQR, 0–20 days], p<0.001). ICU-free days within 28 days were significantly longer in the HFNC group than those in the IMV group (median, 23 days [IQR, 0–28 days] vs. median, 15 days [IQR, 0–20 days], p<0.001). Respiratory failure days were relatively shorter in the HFNC group, but the difference was not statistically significant (p=0.071).Conclusions: Among patients with severe COVID-19-induced respiratory failure, HFNC compared to IMV resulted in a statistically significant increase in ventilator-free and ICU-free days within 28 days without increasing in-hospital mortality. This study showed the potential for HFNC to be an effective alternative to IMV as initial respiratory management for severe COVID-19-induced respiratory failure.