The effect of three different doses of tranexamic acid on blood loss aftercardiac surgery with mild systemic hypothermia (32 degrees C)

Objective: Prophylactic administration of tranexamic acid (TA),an antifibri nolytic agent, decreases bleeding after cardiac surgery with systemic hypot hermia (25 degrees C to 29 degrees C). Warmer systemic temperatures during cardiopulmonary bypass (CPB) may reduce bleeding and thus alter the require ment for TA. The effect of three different doses of TA an bleeding after ca rdiac surgery with mild systemic hypothermia (32 degrees C) is evaluated. Design: Double-blind, prospective, randomized study. Setting: University hospital. Participants: One hundred fifty adult patients undergoing aortocoronary byp ass or valvular cardiac surgery. Interventions:Patients received TA, 50 (n = 50), 100 (n = 50), or 150 (n = 50) mg/kg intravenously before CPB with mild systemic hypothermia. Measurements and Main Results: Blood loss through chest drains over 6, 12, and 24 hours after surgery and total hemoglobin loss were measured. Autotra nsfused blood, transfused banked blood and blood products, and coagulation profiles were measured. Analysis of variance on lag-transformed data far bl ood loss and confidence intervals (Cls) of 0.95 were calculated and transfo rmed to milliliters of blood. No patient was re-explored for bleeding. Bloo d loss at 6 hours was statistically greater in the 50-mg/kg group compared with the other two groups (p = 0.03; p = 0.02). Total hemoglobin loss was s tatistically greater in the 50-mg/kg group compared with the 150-mg/kg grou p (p = 0.04). There was no statistical difference in blood transfusion rate or coagulation profiles among the three groups. However, preoperative hemo globin revel was statistically lower in the 150-mg/kg group compared with t he other two groups (p = 0.01). Conclusion: Of the three doses of TA studied, the most efficacious and cost -effective dose to reduce bleeding after cardiac surgery with mild hypother mic systemic perfusion is 100 mg/kg. Copyright (C) 1998 by W.B. Saunders Co mpany.