Association between prehospital tranexamic acid and cerebral edema in patients with moderate or severe traumatic brain injury

BACKGROUND Traumatic brain injury (TBI) contributes to substantial morbidity and mortality worldwide. Tranexamic acid (TXA) has been shown to reduce mortality in patients with traumatic intracranial hemorrhage (ICH) when given within 2 hours of injury. Although TXA is an antifibrinolytic, most studies have observed no difference in ICH progression; recent studies suggest that TXA may reduce cerebral edema in TBI. Our objective was to determine if prehospital TXA administered within 2 hours of injury is associated with surrogates of cerebral edema in patients with moderate or severe TBI. METHODS We performed a retrospective analysis of a multinational prehospital trial of TXA administered within 2 hours of injury in patients with moderate or severe TBI. Patients with prehospital Glasgow Coma Scale score of <13 and systolic blood pressure of >90 mm Hg were randomized to placebo, 2-g TXA bolus, or 1-g TXA bolus followed by 1 g 8-hour TXA infusion. Patients who received an intracranial pressure (ICP) monitor were selected for analysis. Baseline demographic, injury severity, and infusion characteristics were compared between TXA dosing cohorts. Proportion of hours spent with ICP of >20 mm Hg, cerebral perfusion pressure (CPP) of <60 mm Hg, and need for craniectomy were compared between groups. RESULTS A total of 108 patients with ICP monitors made up the study population (placebo, n = 31; 1 g + 1 g, n = 38; 2-g bolus, n = 39). No differences were identified in age, sex, Abbreviated Injury Scale head, Glasgow Coma Scale, Injury Severity Score, crystalloid and blood product infused in first 24 hours, Marshall score, ICH, or mortality between the three treatment arms. No differences in proportions of hours in which ICP of >20 mm Hg or CPP of <60 mm Hg were identified between treatment arms; rate of craniectomy was also similar. CONCLUSION No association could be identified between TXA treatment and ICP elevation, CPP depression, or need for craniectomy. These results question TXA's potential impact on cerebral edema. Further study is needed to confirm this finding based on the exploratory nature and limited number of subjects in this study. LEVEL OF EVIDENCE Therapeutic/Care Management; Level IV.