Prone Position in Mechanically Ventilated COVID-19 Patients: A Multicenter Study

Background: The prone position (PP) is increasingly used in mechanically ventilated coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS) patients. However, studies investigating the influence of the PP are currently lacking in these patients. This is the first study to investigate the influence of the PP on the oxygenation and decarboxylation in COVID-19 patients. Methods: A prospective bicentric study design was used, and in mechanically ventilated COVID-19 patients, PP was indicated from a partial pressure of oxygen in arterial blood (P-aO2)/fraction of inspired oxygen (F-IO2) ratio of <200. Patients were left prone for 16 h each. Pressure levels, F-IO2, were adjusted to ensure a P-aO2 greater than 60 mmHg. Blood gas analyses were performed before (baseline 0.5 h), during (1/2/5.5/9.5/13 h), and after being in the PP (1 h), the circulatory/ventilation parameters were continuously monitored, and lung compliance (LC) was roughly calculated. Responders were defined compared to the baseline value (P-aO2/F-IO2 ratio increase of >= 15%; partial pressure of carbon dioxide (P-aCO2) decrease of >= 2%). Results: 13 patients were included and 36 PP sessions were conducted. Overall, P-aO2/F-IO2 increased significantly in the PP (p < 0.001). Most P-aO2/F-IO2 responders (29/36 PP sessions, 77%) were identified 9.5 h after turning prone (14% slow responders), while most P-aCO2 responders (15/36 PP sessions, 42%) were identified 13 h after turning prone. A subgroup of patients (interval intubation to PP >= 3 days) showed less P-aO2/F-IO2 responders (16% vs. 77%). An increase in P-aCO2 and minute ventilation in the PP showed a significant negative correlation (p < 0.001). LC (median before the PP = 38 mL/cm H2O; two patients with LC >80 mL/cm H2O) showed a significant positive correlation with the 28 day survival of patients (p = 0.01). Conclusion: The PP significantly improves oxygenation in COVID-19 ARDS patients. The data suggest that they also benefit most from an early PP. A decrease in minute ventilation may result in fewer P-aCO2 responders. LC may be a predictive outcome parameter in COVID-19 patients. Trial registration: Retrospectively registered.