Hepatic disposition of sufentanil in patients undergoing coronary bypass surgery

In order to clarify the relative contribution of the liver to the short-term disposition of sufentanil, hepatic blood flow was measured during induction of anaesthesia with a 10 micrograms/kg i.v. bolus dose of sufentanil followed by a continuous infusion of 0.3 microgram/kg/min of sufentanil. The hepatic clearance of the drug was 0.57 l/min after induction and 0.55 l/min at sternotomy, its hepatic extraction 92% and 91%, respectively. As a consequence of the high hepatic extraction, the hepatic clearance of sufentanil was closely dependent on hepatic plasma flow. Comparing the hepatic clearance of sufentanil with data from the literature for total body clearance of sufentanil, there is a significant difference of more than 0.3 l/min. It is concluded that there is evidence for a relevant extrahepatic disposition of sufentanil.