A Prospective Observational Study of Acute Traumatic Coagulopathy in in Traumatic Bleeding from the Battlefield

Background Acute trauma coagulopathy (ATC) is defined by an admission prothrombin time ratio (PTr) >1.2 or reduced clot amplitude, on viscoelastic testing. It is associated with increased mortality. Whether ATC occurs after military trauma and whether it is similar to civilian ATC has not been studied. Military trauma differs from civilian trauma with most injuries from explosions and high velocity gun-shot wounds (GSW). This study aimed to characterize military ATC, and to explore possible differences due to the mechanism of injury. Methods: Casualties meeting full trauma team activation on admission to a military field hospital in Afghanistan were eligible for enrollment. After routine blood sampling, waste plasma was prepared, frozen and transported to the UK for further analysis. Findings 77% had ATC as defined by PTr >1.2; only 19% had ATC as defined by a ROTEM A5<36mmHg. Coagulation factor levels correlated with degree of shock, with Factor V (p<0.0001), Factor X (p<0.004) and fibrinogen (p=0.005) showing lower levels. Despite reduced coagulation factors, thrombin generation was well preserved. Fibrinolytic markers (plasmin- antiplasmin (PAP), D-dimer and tissue plasminogen activator levels (tPa)) were increased, correlating with the degree of shock. PAP (p<0.0001) and D Dimer (p=0.0008) levels were greater in those injured by explosion compared to GSW's. Only 8% of casualties had ROTEM hyperfibrinolysis. Interpretations: Military trauma causes ATC and is associated with the extent of injury and shock, similar to civilian trauma. This finding means civilian and military treatments can inform each other. Thrombin generation remained normal or high suggesting that ATC is not due coagulation failure. Fibrinogen and FV levels were disproportionately lowered. Fibrinolysis is a key feature, potentially due in part to a tPa surge at the time of injury. Blast injury caused more activation of fibrinolysis than GSW, a novel finding. Funding: Funding was from the Ministry of Defense . Conflict of Interests: There are no conflicts of interest to declare. Ethics Approval Statement: We utilized residual plasma after routine coagulation testing on admission. As this volume was of negligible amount in relation to the patients’ blood loss, a formal ethics submission was not required by the UK Ministry of Defense Research Ethics Committee. The USA army granted ethical approval (log number M-10242) for their study participants. Both agreed that informed consent was not required as this study was a minimal risk to the subjects.