Non-invasive respiratory support in COVID-19 patients outside the intensive care unit: a multicenter study

Introduction: The usefulness of non-invasive respiratory support (NIRS), including high-flow nasal cannula (HFNC), CPAP, and non-invasive ventilation (NIV), in respiratory failure due to COVID-19 is unknown. The aim of the study was to compare the effectiveness of different modalities of NIRS in preventing death or intubation. Methods: Multicenter, retrospective study in 10 hospitals. Patients >18 years-old with COVID-19 pneumonia, hypoxemic acute respiratory failure, and consecutively treated with NIRS started outside the ICU, from March 1 to April 30, 2020, were included. The main outcome was intubation or death at day 28 after the start of NIRS. Hazard ratios (HR) were calculated to compare groups of NIRS using Cox models. Results: 367 patients were included: 155 HFNC (42%), 133 CPAP (36%), and 79 NIV (22%). The mean age was 67±11 years, 72% were men and 71% had ≥2 comorbidities. The median PaO2/FiO2 ratio was 125 (IQR 81-174) mmHg. The unadjusted rate of intubation or death at day 28 was 46% in HFNC, 37% in CPAP, and 62% in NIV (p = 0.007). The 28-day unadjusted overall mortality was 32%; 26% CNAF, 30% CPAP and 47% NIV (p = 0.008). Adjusting for age, sex, obstructive sleep apnea, hospital, and respiratory rate, and taking patients treated with HFNC as reference group, those treated with NIV showed a higher risk of intubation or death (HR 1.87, 95%CI=1.18-2.97), while those treated with CPAP did not show differences (HR 1.02, 95%CI=0.64-1.63). Conclusion: In patients with acute hypoxemic respiratory failure due to COVID-19 treated with NIRS started outside the ICU, NIV shows a higher rate of intubation or death at day 28 compared to those treated with HFNC or CPAP.