Prediction of Massive Transfusion in Trauma Patients in Prehospital and In-hospital: Data From Swiss Trauma Registry (STR)

Since the 2000s, many prognostic scores were developed to predict traumatic haemorrhage. Most of these studies were retrospectives based on registers. Due to missing data on death due to bleeding, these studies chose to predict the massive transfusion risk as a surrogate of haemorrhagic death. These scores include clinical parameters (vital signs), laboratory values (Haemoglobin, lactate, Base excess) and/or imaging (CT or ultrasound) values. The scores showing best performance are the Trauma Associated Severe Haemorrhage (TASH) score, developed and validated on the German register (DGU-Register) and the ABC score developed and validated in the United States of America.

However, the majority of these scores cannot be applied at the trauma scene due to the unavailability of laboratory and imaging values. Therefore, their clinical utility remains unclear. To overcome the need for diagnostic tests, authors have developed and recently validated a clinical prognostic score in identifying trauma patients with, or at risk of, significant haemorrhage based on predicted probabilities of death due to bleeding: BATT score. This score was developed from an international cohort using data from 271 Trauma Centres in 41 countries on 5 continents and uses first clinical parameters at initial assessment. The BATT score predicts death due to bleeding and has been validated on a large population in England and Wales. It could also predict massive transfusion, as a surrogate of haemorrhagic death, earlier at the trauma scene. Its feasibility and external validation would make its clinical utility superior to other scores while identifying a greater number of patients requiring early management.

Our study is an external validation of pre-existing prognostic scores of traumatic haemorrhages (TASH , ABC and BATT score) at different times of care (Scene of Injury, admission at the trauma room) in order to assess their overall performance, discrimination and calibration in the prediction of massive transfusion, and haemorrhagic death. The objective of the study is to assess a comparison of score performances (Overall performance, discrimination and calibration).

Due to the study population (STR), which is partly integrated into the German DGU-Register, the investigators expect good transportability of the TASH score to the Swiss Trauma Registry in terms of overall performance, discrimination and calibration. The ABC score should show lowers results in terms of discrimination due to its validation on small cohorts exclusively in North America. The new BATT score predicting death due to bleeding has been validated on a large English cohort of more than 100,000 patients. It identifies all patients with haemorrhage and not only patients who have received a massive transfusion subject to survival bias. In this context, the BATT score provides good discrimination with only simple physiological variables available at the trauma scene. In case of its external validation on the STR as part of our study, its feasibility would make its clinical utility superior to other pre-existing scores, while identifying a greater number of patients requiring early management. Its application would activate a massive transfusion plan directly at the trauma scene and save precious time.