Establishment of an inflammation-related acute lung injury/acute respiratory distress syndrome rat model supported by venovenous extracorporeal membrane oxygenation

Background: The major concerns for patients who have acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) associated with coronavirus disease 2019 or sepsis and undergone successful venovenous extracorporeal membrane oxygenation (VV ECMO) include a low survival rate and an uncontrollable inflammatory response. This study aimed to introduce an inflammation-related ALI/ARDS rat model supported by VV ECMO that is more suitable for clinical application to assess the immune response and thereby further improve survival after VV ECMO. Methods: Rats were randomly divided into three groups: the sham group, the lipopolysaccharide (LPS) group, and the LPS + ECMO group. ALI/ARDS was induced via intratracheal instillation of LPS in rats. A 5.5 F specially designed bicaval cannulation was placed in the external jugular vein for drainage and reflux. Femoral artery cannulation was used to monitor blood pressure during surgery. Arterial blood gas was measured at baseline and 3 h after VV ECMO support. Finally, lung tissue, bronchoalveolar lavage fluid (BALF) and blood samples were harvested for further evaluation. Results: All LPS-induced ALI/ARDS rats were successfully supported by VV ECMO. The rats survived during the supporting process and maintained effective blood pressure and electrocardiogram (ECG) activity. Compared with the LPS group, VV ECMO support provided oxygen supply to restore lung function and reduced lung injury. Conclusion: We successfully established an inflammation-related ALI/ARDS rat model supported by VV ECMO, in which VV ECMO support alleviated lung injury. Our rat model provides a new tool for immunological research on inflammation-related ALI/ARDS during VV ECMO.