Prediction of mortality and of the need for massive transfusion in casualties arriving at combat support hospitals in Iraq

Abstract

Background: Our purpose was to compare the Revised Trauma Score (RTS) with the new Field Triage Score (FTS) for prediction of mortality (MORT) and of need for massive transfusion (MASS, >or=10 units of packed cells or whole blood) in casualties arriving at combat support hospitals in Iraq.

Methods: Six hundred ninety-two cases were reviewed; 536 had complete data and were included. Total Glasgow Coma Scale score (GCS total) not GCS motor was used. Thus, a modification (FTS 07) of the FTS was calculated, using GCS <8 and systolic arterial pressure (SAP) <100 as cut-points, with range 0 to 2. Variables different by univariate analysis underwent logistic regression analysis (LRA) and areas under the curve for receiver operating characteristic curves (AUC) were calculated. By LRA, probability of an outcome is given by p = e(k)/(1 + e(k)).

Results: By LRA for MORT, k = 0.616 - 0.438 x RTS; AUC = 0.708. When used instead of RTS, FTS 07 provided k = -0.716 - 1.009 x FTS 07; AUC = 0.687 (NS). For MASS, k = 0.638 - 0.115 x RTS - 0.011 x DAP + 0.358 x SI, where DAP is diastolic arterial pressure and SI is shock index, i.e., heart rate or SAP; AUC = 0.638. When used instead of RTS, FTS 07 provided k = -0.740 - 0.376 x FTS 07- 0.011 x DAP; AUC = 0.618 (NS).

Conclusions: RTS emerged as the best predictor of MORT, with FTS 07 a close surrogate. This indicates the effect of impaired mentation on MORT in these data. For prediction of MASS, RTS as well as the heart rate and blood pressure predominated. The advantage of FTS 07 (or original FTS) over RTS is the former's ease of computation.