title: The effect of three different doses of tranexamic acid on blood loss after cardiac surgery with mild systemic hypothermia (32 degrees C).
abstract: OBJECTIVE
  Prophylactic administration of tranexamic acid (TA), an antifibrinolytic agent, decreases bleeding after cardiac surgery with systemic hypothermia (25 degrees C to 29 degrees C). Warmer systemic temperatures during cardiopulmonary bypass (CPB) may reduce bleeding and thus alter the requirement for TA. The effect of three different doses of TA on bleeding after cardiac surgery with mild systemic hypothermia (32 degrees C) is evaluated.
  
  
  METHODS
  Double-blind, prospective, randomized study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  One hundred fifty adult patients undergoing aortocoronary bypass or valvular cardiac surgery.
  
  
  METHODS
  Patients received TA, 50 (n = 50), 100 (n = 50), or 150 (n = 50) mg/kg intravenously before CPB with mild systemic hypothermia.
  
  
  RESULTS
  Blood loss through chest drains over 6, 12, and 24 hours after surgery and total hemoglobin loss were measured. Autotransfused blood, transfused banked blood and blood products, and coagulation profiles were measured. Analysis of variance on log-transformed data for blood loss and confidence intervals (CIs) of 0.95 were calculated and transformed to milliliters of blood. No patient was re-explored for bleeding. Blood 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 statistically greater in the 50-mg/kg group compared with the 150-mg/kg group (p = 0.04). There was no statistical difference in blood tranfusion rate or coagulation profiles among the three groups. However, preoperative hemoglobin level was statistically lower in the 150-mg/kg group compared with the other two groups (p = 0.01).
  
  
  CONCLUSIONS
  Of the three doses of TA studied, the most efficacious and cost-effective dose to reduce bleeding after cardiac surgery with mild hypothermic systemic perfusion is 100 mg/kg.
authors.affiliation: Division of Cardiovascular Surgery, Toronto Hospital, University of Toronto, Ontario, Canada.
authors.forename: J M
authors.initials: JM
authors.lastname: Karski
authors.forename: N P
authors.initials: NP
authors.lastname: Dowd
authors.forename: R
authors.initials: R
authors.lastname: Joiner
authors.forename: J
authors.initials: J
authors.lastname: Carroll
authors.forename: C
authors.initials: C
authors.lastname: Peniston
authors.forename: K
authors.initials: K
authors.lastname: Bailey
authors.forename: M F
authors.initials: MF
authors.lastname: Glynn
authors.forename: S J
authors.initials: SJ
authors.lastname: Teasdale
authors.forename: D C
authors.initials: DC
authors.lastname: Cheng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000933:Antifibrinolytic Agents / Q000008:administration & dosage*; D001780:Blood Coagulation Tests; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001803:Blood Transfusion; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D004311:Double-Blind Method; D005260:Female; D006351:Heart Valves / Q000601:surgery; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014148:Tranexamic Acid / Q000008:administration & dosage*
chemical_list: D000933:Antifibrinolytic Agents; D014148:Tranexamic Acid