Pharmacokinetics of an infusion of propofol during cardiac surgery

We have measured whole blood concentrations and pharmacokinetics of propofol administered as a constant rate infusion during cardiac surgery. Ten patients undergoing elective cardiac surgery involving cardiopulmonary bypass (seven myocardial revascularization and three aortic valve surgery) received a continuous infusion of propofol 4 mg kg-1 h-1 to supplement alfentanil analgesia. Whole blood propofol concentrations were measured by high pressure liquid chromatography. A concentration greater than 1 microgram ml-1 was achieved within 15 min of starting the infusion and remained constant throughout surgery. Volume of distribution, clearance and terminal half-life were similar to those found in non-cardiac patients.