External validation of the emergency trauma score for early prediction of mortality in trauma patients

Abstract

OBJECTIVES:: The Emergency Trauma Score has been developed for early estimation of mortality risk in adult trauma patients with an Injury Severity Score of 16 or higher. Emergency Trauma Score combines four early predictors available at the trauma resuscitation room: age, Glasgow Coma Scale, base excess, and prothrombin time. Our goal was to validate the Emergency Trauma Score in two large external cohorts. As the Injury Severity Score is not accurately known at the time patients present at the resuscitation room, we evaluated the performance of Emergency Trauma Score in all trauma patients. DESIGN:: External validation study using data from two prospectively collected trauma registries. SETTING:: Two academic level 1 trauma centers. PATIENTS:: Adult patients admitted to the hospital after treatment at the trauma resuscitation room. INTERVENTION: Calibration and discrimination of the original Emergency Trauma Score were assessed within each cohort separately. MEASUREMENT AND MAIN RESULTS:: A total of 4,418 consecutive patients were evaluated. Discrimination was good in both validation cohorts, with areas under the receiver-operating curve curves that were even higher (0.94 and 0.92, respectively) than that in the original cohort (0.83). Predicted mortality was systematically too high compared with actual mortality in patients with low-to-medium expected risk (< 25%). Calibration improved in the lower expected risk range after exclusion of patients with Injury Severity Score less than 16. CONCLUSIONS:: The Emergency Trauma Score model performs well in discriminating between trauma patients who will survive and who will not. If applied to all trauma patients, predicted mortality risks are too high in the low-risk category. © 2013 by the Society of Critical Care Medicine.