Preemptive analgesia in children - Does it exist?

Background and Objectives. Preemptive analgesia has been evident in animals, but few adult human studies exist demonstrating this concept exist, and there are fewer still in children. Caudal epidural blocks with local anesthetics are often placed for postoperative analgesia in children. This study evaluated whether these blocks are more effective when placed prior to surgical incision. Methods. Children aged 1-6 years and ASA I and II (n = 51), undergoing elective hemiorrhaphy, orchidopexy, or circumcision were randomly assigned to receive a caudal epidural block with 0.6 ml/kg of 0.25% bupivacaine with 1:200,000 epinephrine, either before incision (n = 28) or after surgery (n = 23). In all patients, anesthesia was induced and maintained with oxygen, nitrous oxide, and halothane, and caudal epidural blocks were placed. Postoperative pain was scored by a blinded observer using a Faces Pain Scale in the recovery room and was also assessed at home by the parents. Analgesic requirement during the 24-hour period was recorded. Results. The Faces Pain Scale scores and analgesic requirements did not differ between the groups, either in the recovery room or at home (P > .05). Conclusions. Although preemptive analgesia has been successfully demonstrated in some earlier clinical studies, our results indicate that pre- and postincisional caudal epidural blocks with 0.25% bupivacaine were equally effective in children.