Background: Traumatic brain injury (TBI) is one of the leading cause of morbidity and mortality in the working class community in various part of the world including India. It is a common cause of coagulopathy, primarily due to blood loss and hemodilution secondary to fluid resuscitation. Traumatic injury-associated coagulopathy often follows a course of transition from hyper to hypocoagulable state exemplified in disseminated intravascular coagulation. The present study aims to ratify the cut-off value of INR to conform a prognostic value in isolated Traumatic Brain Injured patients. Patients and Methods: This was a pilot prospective observational study done at a tertiary care centre in coastal Karnataka. The study design was presented and prior approval was obtained from the Scientific Review Board and Ethics Committee of Kasturba Hospital, Manipal. Written informed consent was obtained from patients or their next-of-kin in accordance to the ethical committee pre-requisites. INR from the patients were tabulated and analysed using commercial software SPSS version 16.0 Results: 105 patients were enrolled for the study with an age range between 18 to 60 years. The patients who were dichotomised based on GCS and GOS. Based on GOS, 89.5% (94) of the patients fell into good prognosis group and 11 (10.5%) into the poor prognosis category. The GCS assessment saw 82 patients (78.1%) to be in the non-high risk category and 23 patients (21.9%) in high risk group. Using the ROC curve (Graph 1), the cut-off value of INR was found to be 1.06. This suggested that INR values lesser than 1.06 were likely to be associated with a better prognosis than those with an INR value which was higher than the cut-off. This was found to have a sensitivity of 59.6% and a specificity of 72.7%. The positive predictive value was at a staggering 94.9% and a negative predictive value of 17.4% with a 61.0% accuracy. Discussion: TBI is also known as acquired brain injury and can be classified in several ways2. Major mechanisms which are pivotal in primary injury are contact and acceleration-deceleration. These in turn cause anatomical and physiological impairment such as intracranial hematoma. There are several mechanisms proposed to explain acute traumatic coagulopathy in Traumatic Brain Injury. One of it is the tissue factor hypothesis. The other proposed hypothesis is explained via over-activation of the protein C pathway6. Trauma causes hypoperfusion and damages the endothelium, thus activating the protein C pathway. Protein C in-turn inhibits coagulation factors; Va and VIIa by cleaving them. Based on the results from this study, one could predict that patients with INR values lesser than or equal to 1.06 would improve significantly as compared to those with a higher INR value. However, at the same time it neither substantiates the need for prophylactic antifibrinolytic agents nor recommends the delay in any neurosurgical intervention8. Conclusion: INR is a good tool in predicting the prognosis in isolated TBI. Nonetheless clinical correlation should be considered before initiation of antifibrinolytic therapy and delaying neurosurgical intervention.

Keywords: Traumatic brain injury (TBI); Prognostic Factor; INR.