Prehospital Transfusion With Red Blood Cells and Fresh Plasma in Helicopter Emergency Medical Services

Prehospital administration of blood products is a growing practice. We aimed to describe clinical parameters and mortality following prehospital blood component therapy with red blood cells (RBC) and/or plasma in patients with traumatic and non-traumatic haemorrhage.

An retrospective cohort study was performed on patients receiving prehospital transfusion products at the Danish national Helicopter Emergency Medical service between 2014 and 2020 with addition of a recent period 2023-2024. Data was collected from relevant data bases and electronic patient journals and analysed descriptively and statistically.

We identified 393 patients who received prehospital transfusion (280 trauma and 113 non-trauma). Prehospital transfusion rate was low (0.9% of missions) with no change during the period studied. Mortality rates for the entire cohort were 13% at 24 h and 26% at 30 days. Trauma patients were significantly younger 49 (IQR; 28-68) vs. 71 (IQR; 60-77)), with lower Glasgow coma score scale; 3 (IQR; 3-14) vs. 15 (IQR; 3-15) and more days on ventilator; 3 (IQR; 1-8) days vs. 2 (IQR; 0-3) days), in intensive care; 5 (IQR; 2-12) days vs. 2 (IQR; 0-4) days) and longer hospital stay 16 (IQR; 6-38) days vs. 8 (IQR; 3-16) days). Lactate trauma-group: 3.2 (IQR; 1.9-5.8), non-trauma: 5.1 (IQR; 2.3-9.4) mmol/L and base excess trauma-group: -4.9 (IQR; -9 to -2.3), non-trauma: -8 (IQR; -15.6 to -4) mmol/L were outside reference range indicating circulatory shock at hospital arrival while standard coagulation parameters were normal or near-normal. Mortality was significantly higher in non-trauma patients as compared with trauma (11% vs. 22%, p = 0.04).

Prehospital transfusion was uncommon, did not change over time and was associated with biochemical parameters near the normal reference range. Twenty-four-hour mortality was higher among non-trauma patients compared with trauma patients.

Some forms of advanced care can be delivered to critically ill or injured patients on their way emergently to hospital, for example in air ambulances. In this cohort of cases which included significant haemorrhage, administration of component blood products was analysed for associations with case conditions and health outcomes.