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 (GCS ≤12, SBP ≥90) received either a 2 g TXA bolus or a 1 g bolus plus 1 g 8 h 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 Chi Square, Fischers Exact Test, t-test, or Mann Whitney U test as indicated. Logistic regression examined time to drug as an independent variable. P < 0.05 was considered significant. RESULTS 649 Patients met inclusion criteria (354 early and 259 late). 28-day and 6-month mortality, 6-month Glasgow Outcome Scale - Extended (GOSE) and disability rating scale scores were not different between early and late administration. Late administration was associated with higher rates of DVT (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). CONCLUSIONS In patients with moderate or severe TBI who received TXA within two 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. LEVEL OF EVIDENCE Level 1, Therapeutic.