Validation of the BATT score for prehospital risk stratification of traumatic haemorrhagic death: usefulness for tranexamic acid treatment criteria

Francois-Xavier Ageron,Timothy J Coats,Vincent Darioli,Ian Roberts

doi:10.1186/s13049-020-00827-5

Abstract

BackgroundTranexamic acid reduces surgical blood loss and reduces deaths from bleeding in trauma patients. Tranexamic acid must be given urgently, preferably by paramedics at the scene of the injury or in the ambulance. We developed a simple score (Bleeding Audit Triage Trauma score) to predict death from bleeding.MethodsWe conducted an external validation of the BATT score using data from the UK Trauma Audit Research Network (TARN) from 1st January 2017 to 31st December 2018. We evaluated the impact of tranexamic acid treatment thresholds in trauma patients.ResultsWe included 104,862 trauma patients with an injury severity score of 9 or above. Tranexamic acid was administered to 9915 (9%) patients. Of these 5185 (52%) received prehospital tranexamic acid. The BATT score had good accuracy (Brier score = 6%) and good discrimination (C-statistic 0.90; 95% CI 0.89–0.91). Calibration in the large showed no substantial difference between predicted and observed death due to bleeding (1.15% versus 1.16%, P = 0.81). Pre-hospital tranexamic acid treatment of trauma patients with a BATT score of 2 or more would avoid 210 bleeding deaths by treating 61,598 patients instead of avoiding 55 deaths by treating 9915 as currently.ConclusionThe BATT score identifies trauma patient at risk of significant haemorrhage. A score of 2 or more would be an appropriate threshold for pre-hospital tranexamic acid treatment.

Highlights

Tranexamic acid (TXA) reduces surgical blood loss and reduces deaths from bleeding in trauma patients [1, 2]
We previously developed a prognostic model to predict death from bleeding and showed that the relative reduction in mortality with TXA does not vary with baseline risk [5, 6]
Pre-hospital treatment of trauma patients with a BATT score of 2 or more would substantially increase the number of premature deaths that could be avoided with TXA

Summary

Results

1.1–1.1 0.053–0.056 1.1–1.2 1.1–1.2 0.00–0.01 0.94–1.05 1.07–1.11 avoided and the number needed to treat for each BATT score threshold when patients are treated as soon as possible in the prehospital setting and within 3 h of injury. A BATT score treatment threshold of 2 corresponds to the treatment of 61,598 patients (59% of major trauma patients included in TARN registry with ISS ≥ 9) and results in 210 deaths avoided (Table 5). A BATT score treatment threshold below 2 resulted in 6 to 14 additional deaths avoided with an additional number needed to treat for one death avoided more than 1000 patients (Table 5, Fig. 3)

Introduction

Discussion

Strengths and limitations