Impact of exposure time in awake prone positioning on clinical outcomes of patients with COVID-19-related acute respiratory failure treated with high-flow nasal oxygen: a multicenter cohort study

Abstract Background: In patients with COVID-19-related acute respiratory failure (ARF), awake prone positioning (AW-PP) reduces the need for intubation in patients treated with high-fow nasal oxygen (HFNO). However, the efects of different exposure times on clinical outcomes remain unclear. We evaluated the efect of AW-PP on the risk of endotracheal intubation and in-hospital mortality in patients with COVID-19-related ARF treated with HFNO and analyzed the efects of diferent exposure times to AW-PP. Methods: This multicenter prospective cohort study in six ICUs of 6 centers in Argentine consecutively included patients>18 years of age with confrmed COVID-19-related ARF requiring HFNO from June 2020 to January 2021. In the primary analysis, the main exposure was awake prone positioning for at least 6 h/day, compared to non-prone positioning (NON-PP). In the sensitivity analysis, exposure was based on the number of hours receiving AW-PP. Inverse probability weighting-propensity score (IPW-PS) was used to adjust the conditional probability of treatment assignment. The primary outcome was endotracheal intubation (ETI); and the secondary outcome was hospital mortality. Results: During the study period, 580 patients were screened and 335 were included; 187 (56%) tolerated AW-PP for [median (p25-75)] 12 (9-16) h/day and 148 (44%) served as controls. The IPW-propensity analysis showed standardized diferences