The effect of tranexamic acid on cochlear blood flow in guinea pigs measured by laser Doppler flowmetry

Objective: This study investigated the vasoactive effect of tranexamic acid on the cochlear blood flow in guinea pigs. Method: 3 ml solution (infusion speed, 0.5 ml/min) containing different concentrations of tranexamic acid was intravenously infused into 15 guinea pigs under general anesthesia. The guinea pigs were grouped according to four levels of dosage of the medicine (470 mg/kg, n=6; 220 mg/kg, n=3; 4 mg/kg, n=3; 1 mg/kg, n=3). Before administering medicine, saline solution was administered in similar volume and speed as a control. The cochleas were surgically exposed and laser Doppler flowmetry monitored cochlear blood flow volume (CBF). The left femoral artery was cannulated to permit a transducer to monitor systemic blood pressure (BP). Results: (1) Stimulatory effect of tranexamic acid on CBF was dose-dependent at concentrations of 1–470 mg/kg and, (2) the time course of changes in CBF was almost identical to that in BP following tranexamic acid administration. Conclusion: Preliminary findings suggest that intravenous administration of tranexamic acid increases CBF due to vasomotorial mechanism effect on BP.