Fibrinogen Levels During Trauma Hemorrhage, Response to Replacement Therapy, and Association with Patient Outcomes

Background: Low fibrinogen levels are known to occur in trauma. However, the extent of fibrinogen depletion during trauma hemorrhage, the response to replacement therapy and association with patient outcomes remain unclear.

Objectives: The study aims were to: characterize admission fibrinogen level and correlate it with factors associated with injury; describe the time course of fibrinogen depletion and response to replacement therapy; determine the correlation of fibrinogen level with rotational thromboelastography (ROTEM) parameters; evaluate the effect of fibrinogen supplementation ex vivo; and establish the association between fibrinogen level and clinical outcomes.

Methods: This was a prospective cohort study of 517 patients. Blood samples were drawn on admission and after admistration of every 4 units of packed red blood cells. Fibrinogen levels were determined with the Clauss method, and global hemostatic competence was assessed with thromboelastometry. The effect of fibrinogen supplementation was assessed in a subgroup of coagulopathic patients.

Results: Low admission fibrinogen level was independently associated with injury severity score (P < 0.01), shock (P < 0.001), and prehospital fluid volume (P < 0.001). Fibrinogen supplementation during transfusion maintained but did not augment fibrinogen levels. Administration of cryoprecipitate was associated with improved survival. ROTEM parameters correlated with fibrinogen level, and ex vivo fibrinogen administration reversed coagulopathic ROTEM parameters. Fibrinogen level was an independent predictor of mortality at 24 h and 28 days (P < 0.001).

Conclusions: Fibrinogen level is decreased in injured patients on admission and is associated with poor outcomes. ROTEM is a rapid means of assessing hypofibrinogenemia. Earlier administration of specific fibrinogen replacement may improve outcomes, and prospective controlled trials are urgently needed.