Tranexamic acid does not prevent rebleeding in an uncontrolled hemorrhage porcine model

Background: Fluid resuscitation after uncontrolled hemorrhage might promote rebleeding and irreversible shock. Tranexamic acid is a procoagulant drug that limits blood loss after surgery of the hip, knee, and heart. We hypothesized that pretreatment with tranexamic acid reduces the rebleeding in uncontrolled hemorrhage and thereby allows safe administration of crystalloid fluid resuscitation. Methods: A 120-minute intravenous infusion of 100 mL/kg of Ringer's solution was given to 24 pigs (mean weight, 20 kg) 10 minutes after lacerating the infrarenal aorta. The animals were randomized to receive an intravenous injection of 15 mg/kg of tranexamic acid or placebo just before starting the resuscitation. Rebleeding events were monitored by two ultrasonic probes positioned proximal and distal to the laceration. Results: Tranexamic acid had no effect on the number of rebleeding events, bled volume, or mortality. The initial bleeding stopped within 4 minutes after the injury. The five animals that died suffered from 4.4 rebleeding events on average, which tripled the total blood loss, whereas the survivors had only 1.3 such events during fluid resuscitation (p < 0.02). At autopsy, death was associated with a larger total hemorrhage; the blood recovered from the abdomen weighed 1.4 kg (median) in nonsurvivors and 0.6 kg in survivors (p < 0.001), with the difference being attributable to rebleeding. Conclusion: Rebleeding events increased the amount of blood lost and the mortality in uncontrolled aortic hemorrhage. Tranexamic acid offered no benefit.