Effect of Prone Position on Oxygenation Parameters of Intubated Patients Due to COVID-19-Related ARDS: Prospective Observational Study

Background: Prone positioning (PP) is widely used to improve oxygenation in acute respiratory distress syndrome (ARDS), but evidence in mechanically ventilated COVID-19 ARDS is heterogeneous. Aim: To evaluate the effect of 16-h daily PP on oxygenation, ventilation, laboratory and radiological parameters in intubated patients with COVID-19-related ARDS. Study Design: In this prospective cohort, 40 intubated patients were followed for 3 days: PP group (n = 20; PaO2/FiO(2) <= 100) and supine position (SP) group (n = 20; PaO2/FiO(2) <= 200). Ventilator settings, oxygenation/ventilation parameters (PaO2, PaCO2, HCO3, lactate, pH and SaO(2)), PaO2/FiO(2) ratio, haematologic/biochemical markers (C-reactive protein (CRP), fibrinogen, D-dimer, ferritin, lymphocyte count, procalcitonin, platelet count and LDH) and daily chest radiographs were recorded. Results: Within-group analyses in the PP group showed significant changes over time in PaO2 (p = 0.024), PaCO2 (p = 0.035), PaO2/FiO(2) (p < 0.001), pH (p = 0.004), fibrinogen (F = 7.600; p = 0.002), procalcitonin (F = 3.828; p = 0.043), platelet count (F = 6.486; p = 0.013), and LDH (F = 8.862; p = 0.002) no significant within group changes were observed in the SP group (fibrinogen, p = 0.068; procalcitonin p = 0.093; platelet p = 0.068; LDH p = 0.227). SaO(2) was higher in the PP group than in the SP group at M3 on Day 2: PP: 92.13 +/- 5.5 vs. SP: 88.24 +/- 6.02%; t = 2.131; mean difference +3.89 (95% CI 0.19 to 7.57; p = 0.040). CRP decreased over time in both groups (PP: p = 0.008; SP: p = 0.001). Radiographically, ground-glass opacities decreased in 70% of PP vs. 25% of SP patients (p = 0.001). Conclusions: This study suggests that the prone position may be more effective in improving clinical and oxygenation parameters in intubated COVID-19 patients with severe ARDS.