Pathophysiology of early trauma-induced coagulopathy: emerging evidence for hemodilution and coagulation factor depletion

Abstract

Background: Trauma patients present with a coagulopathy, termed early trauma-induced coagulopathy (ETIC), that is associated with increased mortality. This study investigated hemostatic changes responsible for ETIC.

Methods: Case-control study of trauma patients with and without ETIC, defined as prolonged prothrombin time (PT), was performed from prospective cohort of consecutive trauma patients who presented to Level I trauma center. Univariate and multivariate analyses were performed.

Results: The case-control study group (n = 91) was 80% male, with mean age of 37 years, 17% penetrating trauma and 7% mortality rate. Patients with ETIC demonstrated decreased common and extrinsic pathway factor activities (factors V and VII) and decreased inhibition of the coagulation cascade (antithrombin and protein C activities) when compared with the matched control patients without ETIC. Both cohorts had evidence of increased thrombin and fibrin generation (prothrombin fragment 1.2 levels, thrombin-antithrombin complexes, and soluble fibrin monomer), increased fibrinolysis (d-dimer levels), and increased inhibition of fibrinolysis (plasminogen activator inhibitor-1 activity) above normal reference values. Patients with versus without ETIC had increased mortality and received increased amount of blood products.

Conclusion: ETIC following injury is associated with decreased factor activities without significant differences in thrombin and fibrin generation, suggesting that despite these perturbations in the coagulation cascade, patients displayed a balanced hemostatic response to injury. The lower factor activities are likely secondary to increased hemodilution and coagulation factor depletion. Thus, decreasing the amount of crystalloid infused in the early phases following trauma and administration of coagulation factors may prevent the development.

Figure 1

Coagation pathway: Intrinsic and extrinsic pathways with the primary activators and inhibitors are diagramed. Activators are demonstrated with solid arrows and inhibitors with dashed arrows. Factors measured in the study are in boxes. Abbreviations: TF (tissue factor), FVII (factor VII), FVIIa (activated factor VII), FVIII (factor VIII), FVIIIa (activated factor VIII), FX (factor X), FXa (activated factor X), FV (factor V), FVa (activated factor V), TAT (thrombin-antithrombin), AT (antithrombin), PT (prothrombin), T (thrombin), FG (fibrinogen), FM (fibrin monomer), F (fibrin), TM (thrombomodulin), TM-T (thrombomodulinthrombin), PS (protein S), PC (protein C), PS-C4BP (protein S- x), TAFI (tissue activatable fibrinolysis inhibitor), TPA (tissue plasminogen activator), UK (urokinase), PAI-1 (plasminogen activator inhibitor- 1),