The relationship between awake prone positioning and need for invasive mechanical ventilation in COVID-19 related acute respiratory distress syndrome

Introduction: Prone positioning (PP) is beneficial in acute respiratory distress syndrome (ARDS) patients with orotracheal intubated (OTI) patient, however further studies are needed for awake patients with ARDS. We aim to evaluate the relationship between the duration and number of PP and the need for invasive mechanical ventilation (IMV) in awake patients with COVID-19 related ARDS (C-ARDS). Methods: This is an observational, single-centred, and retrospective study of 32 patients underwent invasive mechanical ventilation (IMV) and matched 33 non-IMV patients with C-ARDS receiving HFNC (high flow nasal cannula). Independent variables such as total number and duration of PP, clinical features, and patient characteristics were obtained. Logistic regression models were used to investigate variables associated with IMV need. Subsequently, models were adjusted for ROX index, APACHE II and SOFA scores, and LOS (length of stay). Results: The SOFA score, ROX index at 4 h, and LOS differed between groups. PaO2, SpO2, respiratory rate (RR) and ROX index of all patients improved after the first prone position (t = -6,93, p < ,001; t = -7,30, p < ,001; t = 5,35, p < ,001; t = 6,02, p < ,001; respectively). Diagnostic decision-making features of PP number (AUC = 0,690) and PP duration (AUC = 0,723) in predicting the need for IMV were examined with the ROC curve. We found that total number of prone position (aOR: 0,70; [CI %95: 0,51 - 0,96]; p = 0,026) and duration of prone position (aOR: 0,95; [CI %95: 0,92 - 0,99]; p = 0,22) are associated with decreased risk of undergoing IMV. Conclusion: IMV need is negatively correlated with duration and total number of PP in the awake patients with C-ARDS receiving HFNC, even after adjusting for possible confounding factors. To generalise these results, additional studies that are multi-centred and with a larger sample sizes are needed.