Does Preemptive Epidural Morphine Prevent Remifentanil Induced Hyperalgesia

This randomized, double blind, controlled study will perform after obtaining informed consent and ethics approval. American Society of Anaesthesiologist physical status (ASA) I-III 105 patients who undergoing major abdominal surgery in obstetric and gynaecology clinic were recruited to this study. Patients were randomized into the 3 groups with computerized randomization programme. Lumbar epidural catheter will be inserted to the all patients. After than anaesthesia induction will provide with 2 mg/kg propofol and 0.6 mg/kg rocuronium. Desflurane and N2O-O2 will use for anaesthesia maintenance. During surgical operation, 0.3 microgram/kg/h remifentanil infusion will continuous till the end of surgery. In group I, 2 ml serum physiologic (0.9 NaCL)will apply from epidural catheter before surgical incision. In group II, 1 mg morphine will apply from epidural catheter before surgical incision. In group III, 1 mg morphine will apply from epidural catheter at the time point of peritoneum is closed. Epidural patient controlled analgesia will provide with bupivacaine for postoperative analgesia. Postoperative pain will be assessed with numerical pain scale. Postoperative analgesic requirement will be calculated. Hyperalgesia will detect with algometer and von Frey ligaments.