Prehospital predictors of the need for transfusion in patients with major trauma

Abstract

Purpose: Severe haemorrhage is a leading cause of early mortality following major trauma. By early identification of patients at risk, blood transfusion could already be initiated in the prehospital period. Aim of the study was to evaluate the extent to which prehospital lactate and base excess, which are known to be associated with trauma-induced coagulopathy, and additional clinical parameters are associated with the need for early transfusion.

Methods: In this prospective, single-centre observational study, trauma patients treated by a helicopter emergency medical service were included, regardless of the injury severity. Patients with coagulation-influencing drugs in long-term therapy were excluded. Blood samples obtained at the beginning of the prehospital treatment were analysed. Primary outcome was the association of lactate and base excess with the need for early transfusion (resuscitation room or immediate surgery). Receiver operating characteristic curves were created, and the area under the curve (AUROC) was calculated.

Results: Between 2015 and 2018, 21 out of 130 adult trauma patients received blood products during the early in-hospital treatment. Both prehospital lactate and base excess were associated with the transfusion (AUROC 0.731 and 0.798, respectively). The optimal calculated cut-off values were 4 mmol/l (lactate) and - 2.5 mmol/l (base excess). When circulatory instability and suspected relevant bleeding were included, the association further improved (AUROC 0.871 and 0.866, respectively).

Conclusion: Prehospital lactate and base excess could be used in combination with other clinical parameters as indicators of the need for early transfusion. This relationship has yet to be confirmed in the current validation study.

Trial registration: German Clinical Trials Register, www.drks.de (No. DRKS 00009559).

Keywords: Blood gas analysis; Blood transfusion; Emergency medical services; Haemorrhage; Trauma.

Fig. 1

Patients flow chart. Presentation of included patients with prehospital blood samples and reasons for exclusion. TXA tranexamic acid

Fig. 2

Lactate and base excess as transfusion predictors. Receiver Operating Characteristics (ROC) curve for prehospital lactate (a) and base excess (b) as a predictor of the need for early blood transfusion in 130 trauma patients. (area under the curve: a lactate 0.731, b base excess 0.798)

Fig. 3

Combined prediction models for transfusion including lactate and base excess. Receiver Operating Characteristics (ROC) curves for predictors of the need for early blood transfusion in 130 trauma patients. The following parameters were tested individually and in combination to establish the models of scoring: a prehospital lactate > 4 mmol/l; suspected bleeding into the chest, abdomen and/or pelvis as determined by the EMS physician; and cardio-circulatory instability as indicated by systolic blood pressure (SBP) < 100 mmHg (area under the curve: combined model with lactate 0.871, lactate 0.741, suspected bleeding 0.766, cardio-circulatory instability 0.701). b prehospital base excess < − 2.5 mmol/l; suspected bleeding into the chest, abdomen and/or pelvis as determined by the EMS physician; cardio-circulatory instability as indicated by systolic blood pressure (SBP) < 100 mmHg (area under the curve: combined model with base excess 0.866, base excess 0.781, suspected bleeding 0.766, cardio-circulatory instability 0.701)