Intrathecal morphine: effects on perioperative hemodynamics, postoperative analgesia, and stress response for total abdominal hysterectomy

Abstract

Intrathecal opioids provide postoperative analgesia and hemodynamic stability by depressing the neuroendocrine response during the perioperative period. The effects of preoperative intrathecal morphine on perioperative hemodynamics, stress response, and postoperative analgesia were evaluated in patients undergoing abdominal hysterectomy with general anesthesia. A total of 24 patients were randomly assigned to the morphine group (n=12) or the control group (n=12). Patients in the morphine group were given intrathecal 5 microg/kg(-1) morphine before surgery. In all patients, general anesthesia was induced with 1 g/kg(-1) remifentanil, 2 mg/kg(-1) propofol, and 0.1 mg/kg(-1) vecuronium and was maintained with 1% to 2% sevoflurane-35% oxygen in N2O and remifentanil infusion. All patients received intravenous morphine patient-controlled analgesia after surgery. Postoperative pain was evaluated by means of a visual analogue scale. Blood samples were taken at 4 time points before and up to 4 hours after the start of surgery for assessment of plasma epinephrine, norepinephrine, and glucose. Mean arterial pressure (MAP), heart rate (HR), and adverse effects were recorded. Intraoperative hemodynamics was similar in both groups, but postoperative HR and MAP values at 4 h, 8 h, 12 h, and 20 h were significantly lower in the morphine group (P<.05). Postoperative VAS scores, total morphine consumption, and plasma epinephrine, norepinephrine, and glucose levels were significantly lower in the morphine group than in the control group (P<.05). Preoperative intrathecal morphine enhanced the quality of postoperative analgesia, decreased morphine consumption, and depressed the systemic stress response in patients undergoing total abdominal hysterectomy with general anesthesia.