Early Use of Prone Position in ECMO for Severe ARDS

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is widely used in the salvage treatment of critical acute respiratory distress syndrome (ARDS). However, reducing lung injury, accelerating lung recovery, shortening VV-ECMO support time, and decreasing complications during the treatment need further study. By changing the body position of ARDS patients, the prone position can increase the lung's dorsal ventilation and improve the lung's ventilation/blood flow ratio to improve oxygenation. Previous multicenter studies have proved that the prone position can significantly reduce the mortality of patients with moderate and severe ARDS. However, patients with severe ARDS rescue by VV-ECMO rarely combine with a prone position.On the one hand, with the support of ECMO, the patient's oxygenation will be significantly improved, and they will no longer need the assistance of a prone position. In addition, the ECMO cannula brings some challenges to implementing a prone position. Only a few cohort studies have reported that VV-ECMO combined with a prone position could improve the oxygenation index and respiratory system compliance during the late treatment period. The initial reason for PP in ARDS patients was to alleviate severe hypoxemia, as it was an efficient means to improve oxygenation in most patients. However, some patients were categorized as non-responders in the PP regarding oxygenation, which caused VV-ECMO therapy to be initiated. Should we decide to perform PP after VV-ECMO therapy no longer? This study evaluates whether early use of PP during VV-ECMO would increase the proportion of patients successfully weaned from VV-ECMO support compared with supine positioning in severe ARDS patients who received PP before ECMO.