[Preemptive analgesia produced with epidural analgesia administered prior to surgery]

The effect of epidural analgesia administered before or during surgery on postoperative pain relief using continuous epidural infusion of the mixture of local anesthetics and narcotics was studied. Ninety patients undergoing abdominal hysterectomy were randomly allocated to three groups; thirty patients of group 1 who received general anesthesia alone, thirty patients of group 2 with epidural analgesia 20 min before the end of surgery under general anesthesia and thirty patients of group 3 with epidural analgesia plus general anesthesia before surgery. Epidural analgesia was induced with 2% mepivacaine solution 15 ml without epinephrine in group 2 and 3, and in group 3 followed with 5 ml of the same solution at one-hour intervals. General anesthesia was induced with thiamylal and maintained with nitrous oxide, oxygen and sevoflurane. Immediately after surgery, 5 ml of the mixture of 0.225% bupivacaine and 0.0005% fentanyl was injected epidurally and followed with continuous infusion of the same mixture at the rate of 2.1 ml.h-1 over 24 h. Visual analogue score and Prince-Henry score were significantly less in group 3 than in group 1 and group 2 at 4 hours and 24 hours after surgery (P < 0.01, P < 0.05 respectively). These results suggest that postoperative continuous epidural analgesia is more effective if the entrance of noxious stimuli into the central neural system is prevented by preincisional epidural block.