The pre-ECMO simplified acute physiology score II as a predictor for mortality in patients with initiation ECMO support at the emergency department for acute circulatory and/or respiratory failure: a retrospective study

Background: In the emergency department (ED), extracorporeal membrane oxygenation (ECMO) can be used as a rescue treatment modality for patients with refractory circulatory and/or respiratory failure. Serious consideration must be given to the indication, and the PRESERVE and RESP scores for mortality have been investigated. However these scores were validated to predict survival in patients who received mainly veno-venous (VV) ECMO in the intensive care unit. The aim of the present study was to investigate the factors that predicted the outcomes for patients who received mixed mode (veno-arterial [VA] and VV) ECMO support in the ED. Methods: This single center retrospective study included 65 patients who received ECMO support at the ED for circulatory or respiratory failure between January 2009 and December 2013. Pre-ECMO SAPS II and other variables were evaluated and compared for predicting mortality. Results: Fifty-four percent of patients received ECMO-cardiopulmonary resuscitation (E-CPR), 31 % received VA and V-AV ECMO, and 15 % received VV ECMO. The 28-day and 60-month mortality rates were 52 % and 63 %. In the multivariate analysis, only the pre-ECMO Simplified Acute Physiology Score II (SAPS II) (odd ratio: 1.189, 95 % confidence interval: 1.032-1.370, p = 0.016) could predict the 28-day mortality. The area under the receiver operating characteristic curve and the optimal cutoff value for pre-ECMO SAPS II in predicting 28-day mortality was 0.852 (95 % CI: 0.753-0.951, p < 0.001) and 80 (sensitivity of 97.1 % and specificity of 71.0 %), respectively. Validation of the 80 cutoff value revealed a statistically significant difference for the 28-day and 60-month mortality rates in the overall, E-CPR, and VA groups (28-day: p < 0.001, p = 0.004, p = 0.005; 60-month: p < 0.001, p = 0.004, p = 0.020). In the Kaplan-Meier analysis, the 28-day and 60-month survival rates were lower among the patients with a pre-ECMO SAPS II of <= 80, compared to those with a score of >80 (both, p < 0.001). Conclusion: The pre-ECMO SAPS II could be helpful for identifying patients with refractory acute circulatory and/or respiratory failure who will respond to ECMO support in the ED.