Physiological effect of prone positioning in mechanically ventilated SARS-CoV-2- infected patients with severe ARDS: An observational study

BACKGROUND AND AIMS: Mechanical ventilation in prone position was associated with a reduction in mortality and increase in arterial oxygenation in acute respiratory distress syndrome (ARDS) patients. However, physiological effects of prone position in COVID ARDS patients are unknown. MATERIAL AND METHODS: In this prospective observational study, data of n = 47 consecutive real time RT- PCR confirmed SARS-CoV-2-infected patients with severe ARDS were included. Respiratory mechanics and oxygenation data of recruited patients were collected before and after prone position. RESULTS: Median (Interquartile range, IQR) age of the recruited patients was 60 (50–67) years and median (IQR) PaO(2)/FiO(2) ratio of 61.2 (54–80) mm Hg with application of median (IQR) positive end expiratory pressure (PEEP) of 12 (10–14) cm H2O before initiation of prone position. Out of those patients, 36 (77%) were prone responders at 16 hours after prone session, evident by increase of PaO2 by at least 20 mm Hg or by 20% as compared to baseline, and 73% patients were sustained responders (after returning to supine position). Plateau airway pressure (p < 0.0001), peak airway pressure (p < 0.0001), and driving pressure (p < 0.0001) were significantly reduced in prone position, and static compliance (p = 0.001), PaO(2)/FiO(2) ratio (p < 0.0001), PaO(2) (p = 0.0002), and SpO(2) (p = 0.0004) were increased at 4 hours and 16 hours since prone position and also after returning to supine position. CONCLUSION: In SARS-CoV-2-infected patients, mechanical ventilation in prone position is associated with improvement in lung compliance and oxygenation in almost three-fourth of the patients and persisted in supine position in more than 70% of the patients.