Comparison of Four Intensive Care Scores in Predicting Outcomes After Venoarterial Extracorporeal Membrane Oxygenation: A Single-center Retrospective Study

Objective: To assess the capability of the Acute Physiology and Chronic Health Evaluation II (APACHE-II), Sequential Organ Failure Assessment (SOFA) scores, Cardiac Surgery Score (CASUS), and Survival After VA-ECMO (SAVE) in predicting outcomes among a cohort of patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO).

Design: This is an observational retrospective study of 142 patients admitted to the cardiothoracic intensive care unit (CTICU) after undergoing VA-ECMO insertion.

Setting: CTICU of a tertiary care center.

Participants: All patients admitted to the CTICU for a minimum of 24 hours, post-VA-ECMO insertion, between 2015 and 2022.

Interventions: Review of electronic patient records.

Measurements and results: Scores for APACHE-II, SOFA, and CASUS were calculated 24 hours after intensive care units (ICU) admission. The SAVE score was computed from the last available patient details within 24 hours of ECMO insertion. Relevant demographic, clinical, and laboratory data for the study was retrieved from electronic patient records. Pre-ECMO serum levels of lactates and creatinine were significantly associated with mortality. Lower ECMO flow rates at 4 and 12 hours post-ECMO cannulation were significantly correlated with survival to discharge. The development of arrhythmias, acute kidney injury, and the need for continuous renal replacement therapy while on ECMO were significantly associated with mortality. The APACHE-II, SOFA, and CASUS scores, calculated at 24 hours of ICU admission, were significantly higher amongst nonsurvivors. Following risk score categorization using receiver operating characteristic curve analysis, it was found that APACHE-II, SOFA, and CASUS scores calculated 24 hours post-ICU admission after ECMO insertion demonstrated moderate predictive ability for mortality. In contrast, the SAVE score failed to predict mortality. APACHE-II >27 (area under the curve = 0.66), calculated 24 hours post-ICU admission after ECMO insertion, showed the greatest predictive ability for mortality. Multivariate logistic regression analysis of the four scores showed that APACHE-II >27 and SOFA >14, calculated 24 hours post-ICU admission after ECMO insertion, were independently significantly predictive of mortality.

Conclusion: The APACHE-II, SOFA, and CASUS, calculated at 24 hours of ICU admission, were significantly higher among nonsurvivors compared with survivors. The APACHE-II demonstrated the highest mortality predictive ability. APACHE-II scores of 27 or above and SOFA scores of 14 or above at 24 hours of ICU admission after ECMO cannulation can predict mortality and assist physicians in decision-making.