Optimal Timing for Awake Prone Positioning in Covid-19 Patients: Insights from an Observational Study from Two Centers

Background: Given the ease and accessibility of awake prone positioning, its use to improve the oxygenation of patients is common and of interest. However, owing to the lack of consensus on the regimen of awake prone positioning, the effectiveness of awake prone positioning is still unclear.Objective: To explore the optimal regimen for the awake prone positioning treatment, including the timing of initiation, ideal daily duration, and strategies for improving patient comfort and encourage adherenceDesign: Retrospective observational study.Setting(s): Two university-affiliated hospitals in Shanghai.Participants: A total of 475 patients with COVID-19-related pneumonia receiving awake prone positioning were observed between December 2022 and February 2023.Methods: The data were collected from the hospital electronic medical record system. The differentiation efficiency of peripheral blood oxygen saturation [SpO2]: fractional oxygen concentration in inspired air [FiO2] ratio at first awake prone positioning for different outcomes was tested by the area under the receiver operating characteristic curve. Cox proportional hazard regression model was used for analyzing the relationship between time to occurrence of 28-day outcomes and collected variables. Kaplan-Meier curves was plotted with the percentage of 28-day outcomes according to the SpO2:FiO2 ratio at first awake prone positioning after controlling covariates through Cox regression.Results: The best efficiency in predicting patient outcomes was achieved when the cut-off SpO2:FiO2 ratio at the first awake prone positioning was 200. Patients with a reduced SpO2:FiO2 ratio (≤ 200) experienced more adverse respiratory outcomes (RR = 5.42, 95%CI [3.35, 8.76], p < 0·001) and higher mortality (RR = 16.64, 95%CI [5.53, 50.13], p < 0·001). Patients with SpO2:FiO2 ratio at first awake prone positioning＞200, longer duration between first awake prone positioning and admission, more awake prone positioning days, and better awake prone positioning completion were significant protective factors of 28-day adverse respiratory outcomes and mortality.Conclusions: Initialing awake prone positioning with a SpO2:FiO2 greater than 200, more awake prone positioning days, a longer duration between first awake prone positioning and admission, and a better awake prone positioning completion showed significant associations with decreased adverse respiratory outcomes and mortality.