Risk factors for mortality in surgical patients on combined continuous renal replacement therapy and extracorporeal membrane oxygenation: single-center retrospective study

Objective In patients receiving extracorporeal membrane oxygenation (ECMO), continuous renal replacement therapy (CRRT) is increasingly being used for renal replacement and fluid management. However, critically ill surgical patients receiving combined ECMO and CRRT tend to have a high mortality rate, and there are limited studies on this population. Therefore, we aimed to investigate the risk factors for mortality in surgical patients receiving combined ECMO and CRRT.Methods Data of surgical patients who underwent ECMO between December 2013 and April 2023 were retrospectively reviewed. Univariate and multivariate logistic regression analysis were used to identify the risk variables. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff value of albumin and age to predict death.Results A total of 199 patients on ECMO support were screened, of which 105 patients were included in the final analysis. Of 105 patients, 77 (73.33%) were treated with CRRT. Veno-arterial ECMO was performed in 97 cases (92.38%), and the rest were veno-venous ECMO (n = 8, 7.62%). Cardiovascular-related surgery was performed in the main patients (n = 86, 81.90%) and other types of surgery in 19 patients. In surgical patients on ECMO support, the logistic regression analysis showed that CRRT implantation, male sex, and age were the independent risks factors for mortality. Furthermore, the ROC curve analysis showed that age 48.5 years had the highest Youden index. In surgical patients on combined CRRT and ECMO, age, valvular heart disease, and albumin were the independent risk factors for prognosis. Albumin had the highest Youden index at a cutoff value of 39.95 g/L for predicting mortality, though the overall predictive value was modest (area under ROC 0.704). Age had the highest Youden index at a cutoff value of 48.5 years for predicting mortality.Conclusions In our cohort of surgical patients requiring ECMO, which consisted mostly of patients undergoing cardiovascular surgery requiring VA-ECMO, the need for CRRT was an independent risk factor for mortality. In the subset of patients on combined CRRT and ECMO, independent risk factors for mortality included higher age, lack of valvular heart disease, and lower serum albumin.