The role of intrathecal morphine in the anesthetic management of patients undergoing coronary artery bypass surgery.

The study was undertaken to assess the effects of intrathecal morphine (ITM) on perioperative hemodynamics, and anesthetic and postoperative analgesic requirements in patients anesthetized with fentanyl/enflurane undergoing coronary artery bypass surgery. Forty patients were randomized in a double-blind fashion to receive either intrathecal morphine or saline. Nineteen patients received ITM, 0.02 mg/ kg, and 21 intrathecal saline (ITS) after induction of anesthesia. Anesthesia included fentanyl, 40 microg/kg, and pancuronium, 0.15 mg/kg, and was supplemented with enflurane when systolic blood pressure was 20% higher than ward pressure. Intrathecal morphine did not improve hemodynamic stability or reduce enflurane requirements perioperatively. No significant difference was found between ITM and ITS groups for postoperative requirements of morphine (3.5 +/- 0.5 v 4.5 +/- 0.6 mg), diazepam (5.6 +/-1.25 v 3.9 +/- 1.26 mg), and vasodilators (6 v 13 patients), respectively. Comparable and significant reductions of peak expiratory flow rates (PEFR), forced vital capacity (FVC), and forced expiratory volume (FEV1) occurred in both groups postextubation when compared with preoperative values. Intrathecal morphine at the dose of 0.02 mg/kg does not offer any clear benefit to patients anesthetized with fentanyl, 40 microg/kg, for coronary artery bypass surgery.