Effects of Preoperative Epidural Block with Low Dose Bupivacaine and Morphine on Postoperative Pain, Plasma Cortisol and Serum Glucose in Total Abdominal Hysterectomy

복식전자궁적출술에서 술전 저용량 국소마취제와 Morphine을 이용한 경막외차단이 술후통증, 혈장 Cortisol, 혈당에 미치는 영향

Background: Preoperative blocking of surgical nociceptive inputs may prevent sensitization of central nervous system (CNS) and reduce postoperative pain. The stress responses to surgical trauma consist of increase in catabolic hormones and decrease in anabolic hormones. We studied whether preoperative low dose epidural bupivacaine and morphine could affect postoperative pain, changes plasma cortisol, and serum glucose. Methods: Thirty patients undergoing total abdominal hysterectomy were randomly assigned to one of three groups. General anesthesia was induced in all patients and after that, epidural blocks were done except the control group (n=10) patients. Preoperative block group (n=10) received 0.5% bupivacaine 50 mg and morphine 2 mg epidurally as a bolus before operation and followed by 0.1% bupivacaine $5\;mghr^{-1}$ and morphine $0.2\;mghr^{-1}$ for 10 hours. Postoperative block group (n=10) received the same doses of bupivacaine and morphine under the same method postoperatively. Postoperative pain relief was provided with i.v. fentanyl through Patient-Controlled-Analgesia Pump. Postoperative pain by visual analogue scores (VAS), analgesic requirement (first requirement time, total amounts used), side effects, plasma cortisol level and serum glucose level were compared. Results: Until postoperative 6 hrs, VAS of control group was higher than those of the epidural groups. No difference was observed in VAS between the two epidural groups. First analgesics requirement time and total amounts of used analgesics were not different between the two epidural groups, but first analgesic requirement time of preoperative block group was significantly prolonged compared with control group. Plasma cortisol and serum glucose levels were not different among groups. Conclusions: Low dose preoperative epidural bupivacaine and morphine could not reduce postoperative pain, plasma cortisol level and serum glucose level compared with postoperative block group.