ABSTRACT
BACKGROUND: It is necessary to reduce hyperexcitable sensations induced by painful stimulus by preventing central sensitization, so called preemptive analgesia. We observed the effect of butorphanol on postoperative pain after hysterectomy so as to direct analgesic action based on elucidation of the preemptive effect. METHODS: We selected thirty-six patients undergoing elective total abdominal hysterectomy, ASA Physical Status I or II, and employed a double-blind cross-over design. Patients were randomly allocated to one of both groups, receiving intravenous butorphanol 2 mg, either preincisionally or postoperatively. Anesthesia was induced with thiopental and maintained with isoflurane. Patients received meperidine on request for postoperative pain. Patients checked the VAS of spontaneous incisional pain and movement-associated pain by themselves.The time of first demand for postoperative meperidine and the amount of postoperative meperidine for the first 6 hours and 6 to 48 hours were recorded. RESULTS: At 5 hours after surgery, the postoperative VAS score of the preincisional group was lower than that of the postoperative group, and at 24 hours after surgery, the former was also lower than the latter. The first time of demand for postoperative meperidine was earlier in the postoperative group than in the preincisional group. The amount of meperidine for the postoperative first 6 hours was less in the preincisional group than in the postoperative group. CONCLUSIONS: Preincisional intravenous butorphanol reduced the intensity of spontaneous incisional pain and movement-associated pain, regarded as a preemptive effect of butorpahnol, in the early postoperative period.