Severity of head injury is associated with increased risk of coagulopathy in combat casualties

Background: Traumatic brain injury (TBI) is believed to cause more profound trauma-induced coagulopathy than other injuries of comparable severity. This has not been reported in a large series of combat casualties in which penetrating injuries predominate. Methods: Among US combat casualties severely injured in Iraq and Afghanistan who received transfused blood products, isolated TBI patients (head Abbreviated Injury Score [AIS] ≥3 and all other AIS <2) were compared with non-TBI patients (head AIS ≤2 and any other AIS ≥3) to determine the degree to which TBI is associated with coagulopathy as measured by International Normalized Ratio (INR) and to describe characteristics of this population. Stepwise multiple regression analysis was also performed on all US casualties who received transfused blood products to analyze independent predictors of coagulopathy. Results: We compared 117 patients with isolated TBI and 1,492 patients with non-TBI injuries. Admission INR was significantly higher in TBI patients. There were no differences in age, admission base deficit, systolic or diastolic blood pressure, or hemoglobin. On stepwise multiple regression, base deficit, Glasgow Coma Scale, and head AIS score were independently associated with increased coagulopathy as measured by INR. Conclusion: Patients with severe combat-related trauma and isolated TBI had worse coagulopathy than non-TBI patients. Base deficit, Glasgow Coma Scale, and severity of head injury, as reflected by head AIS, are independently associated with increased coagulopathy as measured by INR.