Pharmacokinetics of ketamine during hypothermic cardiopulmonary bypass in cardiac patients.

摘要: Cardiopulmonary bypass (CPB) makes prediction of any drug concentration diffcult because both hypothermia and hemodilution can alter the pharmacokinetics drug. Eleven patients undergoing cardiac surgery under CPB were anesthetized with continuous infusion ketamine combined intermittent administration droperidol fentanyl. The rate was 2 mg·kg−1·hr−1 following a bolus 1.5 mg·kg−1 for induction anesthesia. Blood concentrations its main metabolite, norketamine, measured at 0, 30, 60 min after start end CPB, 1, 2, 24 h cessation infusion. Hypothermia increased blood levels during but norketamine did not change. Although acute would decrease levels, their already significantly 30 CPB. Hypothermic factors have more kinetically important role than hemodilution. Increases in rewarming indicate that could impair metabolism liver. Further increase plasma until might be due to transfusion containing from reservoir.