Postoperative Voiding Interval and Duration of Analgesia Following Peripheral or Caudal Nerve Blocks in Children

We studied the time to postoperative micturition and the duration of analgesia in 82 children aged 6 mo to 10 yr undergoing herniorrhaphy or orchiopexy under general anesthesia with N2O and halothane. All received D5 lactated Ringerʼs solution equivalent to 6 h maintenance intraoperatively, and oral fluids postoperatively ad libitum. At the end of surgery, patients were randomly assigned to receive one of three regional anesthetic injections using 0.25% bupivacainecaudal, 0.75 mL/kg (group I); caudal with 1:200,000 epinephrine, 0.75 mL/kg (group II); or ilioinguinal-iliohypogastric nerve block with epinephrine through the wound by the surgeon (group III). Postoperatively, blinded observers scored pain at 30 min, hourly until discharge, and by telephone at 24--36 h. In the 74 patients with successful blocks (mean age 2.5 ± 2.4 yr), the times to micturition (group 1,202 ± 130 min; group II, 262 ± 164 min; group III, 196 ± 101 min) did not differ significantly among groups. Seven patients who took more than 8 h to void required no intervention. There was no difference in the numbers without pain for ≥4 h (74%, 64%, and 69% of groups I, II, and III), or those requiring analgesics by 24 h (66% overall). The time to postoperative voiding in children is variable and not prolonged by caudal analgesia; caudal bupivacaine with or without epinephrine and ilioinguinal-iliohypogastric nerve block are equally effective for postoperative analgesia.