Comparison of four intensive care scores in prediction of outcome after Veno-Arterial ECMO: A single center retrospective study

Background: Assess the ability of APACHE II (acute physiology and chronic health evaluation II), SOFA (sequential organ failure assessment scores), Cardiac Surgery Score (CASUS) and SAVE (Survival after VA-ECMO) to predict outcomes in a cohort of patients undergoing Veno-Arterial ECMO (VA-ECMO) Methods: Observational retrospective study of all patients admitted to Cardiothoracic Intensive Care Unit (CTICU) for a minimum duration of 24 hours after undergoing VA-ECMO insertion between years 2015 to 2022. Scores for APACHE II, SOFA and CASUS were calculated at 24 after ICU admission. SAVE score was calculated from the last available patient details within 24 hours of ECMO insertion. Demographic, clinical, and laboratory data relevant for the study was retrieved from electronic patient records. Results: Pre-ECMO serum levels of lactates and creatinine were significantly associated with mortality. Lower ECMO flow rates at 4 hours and 12 hours after ECMO cannulation was significantly associated with survival to discharge. Development of arrythmias, acute kidney injury (AKI) and need of continuous renal replacement therapy (CRRT) while on ECMO were significantly associated with mortality. The APACHE-II, SOFA and CASUS, calculated at 24 hours of ICU admission were significantly higher amongst non-survivors. Following categorization of risk scores using ROC curve analysis, it was found that APACHE-II, SOFA and CASUS calculated at 24 hours of ICU admission after ECMO insertion demonstrated moderate predictive ability for mortality whereas SAVE score failed to predict mortality. APACHE-II >27 (AUC of 0.66) calculated at 24 hours of ICU admission after ECMO insertion, demonstrated the greatest predictive ability, for mortality. Multivariate logistic regression analysis of the four scores showed that APACHE-II > 27 and SOFA > 14 calculated at 24 hours of ICU admission after ECMO insertion, were independently significantly predictive of mortality Conclusions: The APACHE-II, SOFA and CASUS, calculated at 24 hours of ICU admission were significantly higher amongst non-survivors as compared to survivors. APACHE-II demonstrated the best mortality predictive ability. APACHE-II scores of 27 or above, and SOFA of 14 or above at 24 hours of ICU admission after ECMO cannulation can predict mortality and will aid physicians in decision making