The effects of timing of prehospital tranexamic acid on outcomes after traumatic brain injury: Subanalysis of a randomized controlled trial

BACKGROUND: Tranexamic acid (TXA) is an antifibrinolytic that has shown some promise in improving outcomes in traumatic brain injury (TBI), but only when given early after injury. We examined the association between timing of prehospital TXA administration and outcomes in patients with moderate to severe TBI. METHODS: Patients enrolled in the multi-institutional, double-blind randomized prehospital TXA for TBI trial with blunt or penetrating injury and suspected TBI (Glasgow Coma Scale score ≤ 12, SBP ≥90) who received either a 2-g TXA bolus or a 1-g bolus plus 1 g 8 hour infusion within 2 hours of injury were analyzed. Outcomes were compared between early administration (<45 minutes from injury) and late administration ≥45 minutes from injury) using a χ², Fischer's exact test, t test, or Mann-Whitney U test as indicated. Logistic regression examined time to drug as an independent variable. A p value less than 0.05 was considered significant. RESULTS: Six hundred forty-nine patients met inclusion criteria (354 early and 259 late). Twenty-eight-day and 6-month mortalities, 6-month Glasgow Outcome Scale–Extended, and disability rating scale scores were not different between early and late administration. Late administration was associated with higher rates of deep venous thrombosis (0.8 vs. 3.4%, p = 0.02), cerebral vasospasm (0% vs. 2%, p = 0.01), as well as prolonged EMS transport and need for a prehospital airway (p < 0.01). CONCLUSION: In patients with moderate or severe TBI who received TXA within 2 hours of injury, no mortality benefit was observed in those who received treatment within 45 minutes of injury, although lower rates of select complications were seen. These results support protocols that recommend TXA administration within 45 minutes of injury for patients with suspected TBI.