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. Th e guinea pigs were grouped according to four levels of dosage of the medici ne (470 mg/kg, n = 6; 220 mg/kg, n = 3; 4 mg/kg, n = 3; 1 mg/kg, n = 3). Be fore administering medicine, saline solution was administered in similar vo lume and speed as a control. The cochleas were surgically exposed and laser Doppler flowmetry monitored cochlear blood flow volume (CBF). The left fem oral artery was cannulated to permit a transducer to monitor systemic blood pressure (BP). Results: (1) Stimulatory effect of tranexamic acid on CBF w as 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 intraven ous administration of tranexamic acid increases CBF due to vasomotorial mec hanism effect on BP. (C) 2001 Elsevier Science Ireland Ltd. All rights rese rved.