EFFECT OF TEMPERATURE AND CARDIOPULMONARY BYPASS ON THE PHARMACOKINETICS OF REMIFENTANIL

Sixteen patients undergoing coronary revascularization requiring cardi opulmonary bypass received remifentanil 2 mu g kg(-1) or 5 mu g kg(-1) by infusion over 1 min after sternotomy but before commencing cardiop ulmonary bypass, during hypothermic cardiopulmonary bypass and during cardiopulmonary bypass after rewarming. Hypothermic cardiopulmonary by pass reduced the clearance of remifentanil by an average of 20%, and t his was attributed to the effect of temperature on blood and tissue es terase activity. Reductions in arterial pressure occurred with adminis tration of both doses during normothermia only.