Reducing Postoperative Hemorrhage

Hyperfibrinolysis is a risk factor for bleeding. Antifibrinolytic drugs have been used in veterinary medicine to reduce postoperative hemorrhage in greyhounds, a breed at greater risk for postoperative bleeding complications. In humans, tranexamic acid (TEA) and ε-aminocaproic acid (EACA) inhibit fibrinolysis. This study sought to determine the minimum plasma concentrations of TEA and EACA needed to completely inhibit fibrinolysis in canine blood after induction of in vitro hyperfibrinolysis. The concentration of EACA and TEA needed to inhibit fibrinolysis was 511.7 µg/mL and 144.7 µg/mL, respectively. This study confirmed that dogs are hyperfibrinolytic compared to humans.

Commentary

The use of antifibrinolytic agents (TEA and EACA) has increased in veterinary patients for treatment of observed or anticipated postoperative hemorrhage. Although evidence has supported the notion that these drugs may reduce postoperative complications in dogs, ideal therapeutic blood concentrations and doses have not been established. This study demonstrates that higher concentrations of TEA or EACA are necessary to inhibit in vitro fibrinolysis in canine plasma as compared with human plasma. This work opens the door for further pharmacokinetic studies, which will bring veterinarians closer to establishing antifibrinolytic treatment protocols for dogs. Once dose ranges have been established, our profession will be better-suited to assess therapeutic efficacy. Although antifibrinolytic treatment already shows promise in reducing postoperative hemorrhage in greyhounds, additional benefits (and possibly additional complications) may be observed when higher doses are used in dogs.—Julie Walker, DVM, DACVECC

This capsule is part of the One Health Initiative.