Abstract
Alfentanil and propofol total intravenous anaesthesia was assessed in 25 patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass (CPB). A manually controlled alfentanil infusion, calculated from estimated lean body mass and published pharmacokinetic data, was effective in achieving target plasma concentrations, while the “Diprifusor” system was used to vary propofol target concentrations according to changes in haemodynamics and anaesthetic requirement. The effects of CPB on alfentanil plasma concentrations were offset by changes in protein binding and free-fraction of the drug. With the use of only two target plasma concentrations for alfentanil (changed after CPB), a pre-determined infusion profile ensured effective plasma concentrations during surgery and concentrations unlikely to inhibit extubation within six hours of sternal closure.