Acute traumatic coagulopathy and hypofibrinogenemia in trauma patients who receive prehospital transfusion: a retrospective cohort study

Prolonged prehospital transport intervals, which are common in the Canadian context due to large geographic catchment areas, are associated with increased risk and severity of acute traumatic coagulopathy. We sought to describe the incidence of acute traumatic coagulopathy (international normalised ratio [INR] > 1.5) and hypofibrinogenemia (fibrinogen < 1.5 g/L) at trauma centre admission in trauma patients transported by helicopter air ambulance who received prehospital transfusion in this context. We conducted a retrospective cohort study of trauma patients transported by Ornge air ambulance to either of two adult trauma centres in Toronto, Canada, between August 2021 and July 2024 who received prehospital transfusion from Ornge’s blood-on-board program. This study was intended as a pilot for future larger-scale studies of this nature. We identified patients from Ornge’s health administrative database and linked them to hospital trauma registries using indirect identifiers. Patient characteristics, prehospital interventions, admission laboratory parameters, hospital interventions and patient outcomes were analysed. A total of 70 patients were analysed. Blunt trauma was predominant (69/70, 99%), and median out-of-hospital time was 131 min (Interquartile Range 102–159). Among patients with an INR recorded, 10/62 (16%) had an INR > 1.5. Among patients with a recorded fibrinogen level, 12/61 (20%) had fibrinogen < 1.5 g/L. Following arrival in the emergency department, 35/70 (50%) of patients had massive haemorrhage protocol activation within one hour; 23/70 (33%) of patients underwent surgical intervention within four hours; 17/70 (24%) of patients received interventional angiography within four hours; and 15/70 (21%) of patients died in-hospital. In univariable analysis, INR > 1.5 on trauma centre arrival was associated with increased mortality ( p = 0.04) and increased massive haemorrhage protocol (MHP) activation ( p = 0.008). Hypofibrinogenemia on trauma centre arrival was not significantly associated with MHP activation ( p = 0.54); however, patients with both acute traumatic coagulopathy and hypofibrinogenemia displayed a higher risk of MHP activation than those with acute traumatic coagulopathy alone ( p = 0.001). Acute traumatic coagulopathy (ATC) and hypofibrinogenemia (HF) at trauma centre admission were common in this cohort, and ATC was associated with higher mortality and MHP activation. While further research is needed to determine the optimal prehospital strategy, current evidence is already sufficient to support implementing targeted interventions and specific blood product additions to optimise prehospital damage-control resuscitation and improve outcomes. Clinical Trials Ontario (4541).