Trauma, shock, and disseminated intravascular coagulation: lessons from the classical literature

Abstract

A trauma patient's survival depends on the ability to control 2 opposing conditions, bleeding at the early phase and thrombosis at a late phase of trauma. The mixed existence of physiological responses for hemostasis and wound healing and pathological hemostatic responses makes it difficult to understand the mechanisms of the 2 stages of coagulopathy after trauma. Traumatic coagulopathy is multifactorial but disseminated intravascular coagulation (DIC) with the fibrinolytic phenotype is the predominant and initiative pathogenesis of coagulopathy at the early stage of trauma. High levels of inflammatory cytokines and severe tissue injuries activate the tissue-factor-dependent coagulation pathway followed by massive thrombin generation and its activation. Low levels of protein C and antithrombin induce insufficient coagulation control and the inhibition of the anticoagulation pathway. Primary and secondary fibrin(ogen)olysis is highly activated by the shock-induced tissue hypoxia and disseminated fibrin formation, respectively. Consumption coagulopathy and severe bleeding are subsequently observed in trauma patients. Persistently high levels of plasminogen activator inhibitor-1 expressed in the platelets and endothelium then change the DIC with the fibrinolytic phenotype into the thrombotic phenotype at approximately 24 to 48 hours after the onset of trauma. All of these changes coincide with the definition of DIC, which can be clearly distinguished from normal responses for hemostasis and wound healing by using sensitive molecular markers and DIC diagnostic criteria such as those outlined by the Japanese Association for Acute Medicine and the International Society on Thrombosis and Haemostasis. Treatments of DIC with the fibrinolytic phenotype involve the surgical repair of the trauma, improvement of shock, and the rapid and sufficient replacement of platelet concentrate, fresh frozen plasma, and depleted coagulation factors. The administration of an antifibrinolytic agent (tranexamic acid) may reduce the risk of death in bleeding trauma patients associated with this type of DIC.