463CAN J ANESTH 2000 / 47: 5 / pp [463][464][465][466] Purpose: Intrathecal morphine administered prior to coronary artery revascularization (CABG) surgery was studied to determine its effects on the stress response.Methods: In a single centre, open, randomized clinical trial, first time elective CABG surgery patients, < 75 yr, were studied. Control subjects (n=12) received a standardized anesthetic consisting of fentanyl (maximum cumulative dose of 35 µg·kg -1 ), propofol, and pancuronium. In addition, spinal subjects (n=13) received 1.0 mg (age > 60 yr) or 1.5 mg (age # 59 yr) intrathecal morphine prior to induction of anesthesia. Control subjects received continuous iv morphine at 2 mg·hr -1 on arrival in the ICU with iv bolus morphine supplementation as required while spinal subjects received bolus iv morphine as required. Changes in plasma cortisol and catecholamine concentrations were measured preoperatively, poststernotomy, on admission to ICU, following tracheal extubation, at 0800 hr on the first postoperative day, and 24 and 48 hr after ICU admission.