Survival Prediction for Non–Asphyxia-Related Hypothermic Cardiac Arrest Patients After Extracorporeal Rewarming: Development of the HELP Score

The aim of this study was to develop a scoring tool to estimate the probability of survival following extracorporeal rewarming in patients suffering hypothermic cardiac arrest. This is a multicenter retrospective study based on registry data. We included adult patients with hypothermic cardiac arrest not associated with asphyxia, with a core temperature of ≤28°C, who underwent extracorporeal rewarming. A multivariable logistic regression model was developed to serve as the predictive tool. Internal validation with bootstrap resampling was performed to adjust model parameters and reduce model optimism. Our study population included 141 patients. The survival rate was 46% (65/141). A total of 88% of the survivors (57/65) had a favorable neurological outcome (Cerebral Performance Category 1-2). The predictive model includes four variables. Outdoor occurrence of hypothermia and a higher hemoglobin level raise survival odds while higher concentrations of potassium and lactate reduce survival odds. The area under the receiver operating characteristic (ROC) curve was 0.812 and p value of the Hosmer-Lemeshow test was 0.8. We developed a prognostic model to estimate the probability of survival in adult patients with non-asphyxia-related hypothermic cardiac arrest. This model may aid in identifying candidates suitable for extracorporeal rewarming, though it should not be used as the sole deciding factor.