Association between the peak red blood cell distribution width and in-hospital mortality after post-cardiotomy extracorporeal membrane oxygenation

Red blood cell distribution width (RDW) is a marker that routinely describes circulating erythrocytes variability and may hold potential prognostic value in cardiac surgery. Our objective is to evaluate the association between peak values of RDW and in-hospital mortality among patients receiving post-cardiotomy veno-arterial extracorporeal membrane oxygenation (V-A ECMO) support. This single-center, retrospective study included adult patients receiving post-cardiotomy V-A ECMO support between January 2017 and December 2024. The association between peak values of RDW and in-hospital mortality was assessed by multivariable logistic regression model. Spearman correlation analysis was used to determine the correlations between related laboratory factors and peak values of RDW. A total of 106 patients were included and in-hospital mortality rate was 54.7%. After adjusting for confounding factors, increased peak values of RDW during ECMO support were significantly associated with higher risk of in-hospital mortality (aOR, 2.097; 95% CI, 1.328–3.312; p = 0.001). Peak values of RDW were negatively correlated with lowest values of hemoglobin and positively correlated with peak values of lactate dehydrogenase (LDH), direct bilirubin (DBil), total bilirubin (TBil), neutrophil-to-lymphocyte ratio (NLR) and fibrinogen degradation products (FDP) occurring within ± 12 h of the RDW peak levels. In patients receiving post-cardiotomy V-A ECMO, the peak values of RDW might be an independent prognostic factor for in-hospital mortality. Potential factors related to increased peak values of RDW included hemolysis, systemic inflammatory responses, and coagulation dysfunction.