Pharmacokinetics of tranexamic acid during cardiopulmonary bypass.

Background: Tranexamic acid (TA) reduces blood loss and blood transfusion during heart surgery with cardiopulmonary bypass (CPB). TA dosing has been empiric because only limited pharmacokinetic studies have been reported, and CPB effects have not been characterized. We hypothesized that many of the published TA dosing techniques would prove, with pharmacokinetic modeling and simulation, to yield unstable TA concentrations.