Severity of metabolic derangement predicts survival after out-of-hospital cardiac arrest and the likelihood of benefiting from extracorporeal life support

To develop a Metabolic Derangement Score (MDS) based on parameters available after initial testing and assess the score's ability to predict survival after out-of hospital cardiac arrest (OHCA) and the likely usefulness of extracorporeal life support (ECLS). A total of 5100 cases in the Korean Cardiac Arrest Research Consortium registry were included. Patients' mean age was 67 years, and 69% were men. Findings from initial tests (pH; PaCO2; PaO2; and potassium, hemoglobin, lactate, and creatinine levels) were extracted from the registry. The primary composite outcome was death or poor neurologic outcome (Cerebral Performance Category Scale, $ 3) at 30 days. We developed the model for the MDS using automated machine learning algorithms in a development cohort (60% of the patients) and tested it in a validation cohort (40%). Risk for the primary outcome increased by 34% as the MDS rose from 0 to 7 in the test cohort. Patients with scores of 2 or lower had no increased risk for the outcome according to whether ECLS had been used or not. However, ECLS patients with a score of 3 or more did have lower risk for the outcome, based on a restricted mean survival time of 6.5 days and a ratio of restricted mean time lost of 0.76; P .001, both comparisons). Registered test results were consistent between patients who did or did not receive ECLS. The MDS predicted the composite outcome better than the OHCA, Cardiac Arrest Hospital Prognosis, and NULL-PLEASE scores (P .05). The MDS we developed predicts prognosis in patients with OHCA and identifies patients who could benefit from ECLS.