The coagulopathy of trauma.

Trauma is a leading cause of death, with uncontrolled hemorrhage and exsanguination being the primary causes of preventable deaths during the first 24 h following trauma. Death usually occurs quickly, typically within the first 6 h after injury. One out of four patients arriving at the Emergency Department after trauma is already in hemodynamic and hemostatic depletion. This early manifestation of hemostatic depletion is referred to as the coagulopathy of trauma, which may distinguished as: (i) acute traumatic coagulopathy (ATC) and (ii) iatrogenic coagulopathy (IC). The principle drivers of ATC have been characterized by tissue trauma, inflammation, hypoperfusion/shock, and the acute activation of the neurohumoral system. Hypoperfusion leads to an activation of protein C with cleavage of activated factors V and VIII and the inhibition of plasminogen activator inhibitor-1 (PAI-1), with subsequent fibrinolysis. Endothelial damage and activation results in Weibel-Palade body degradation and glycocalyx shedding associated with autoheparinization. In contrast, there is an IC which occurs secondary to uncritical volume therapy, leading to acidosis, hypothermia, and hemodilution. This coagulopathy may, then, be an integral part of the "vicious cycle" when combined with acidosis and hypothermia. The awareness of the specific pathophysiology and of the principle drivers underlying the coagulopathy of trauma by the treating physician is paramount. It has been shown that early recognition prompted by appropriate and aggressive management can correct coagulopathy, control bleeding, reduce blood product use, and improve outcome in severely injured patients. This paper summarizes: (i) the current concepts of the pathogenesis of the coagulopathy of trauma, including ATC and IC, (ii) the current strategies available for the early identification of patients at risk for coagulopathy and ongoing life-threatening hemorrhage after trauma, and (iii) the current and updated European guidelines for the management of bleeding and coagulopathy following major trauma.