Timing of Caudal Block Placement in Relation to Surgery Does Not Affect Duration of Postoperative Analgesia in Paediatric Ambulatory Patients

The purpose of this study was to determine if the timing of caudal block placement in relation to surgery affected either the duration of postoperative pain relief or the discharge time in children undergoing brief ambulatory surgical procedures. Forty ASA physical status I or II children ages 18 mo to 11 yr were randomly assigned to one of two groups. Group 1 patients received a caudal block with 0.5 ml.kg-1 of bupivacaine 0.25 per cent following the induction of anaesthesia but before the onset of surgery. Group 2 patients received a similar block at the completion of surgery but before emergence from general anaesthesia. An experienced observer, who was not aware of the timing of block placement, observed all patients from arrival to the post-anaesthetic recovery room until discharge from the ambulatory surgery unit. Pain was assessed at five-minute intervals using an Objective Pain Scale. No statistically significant differences were noted between Group 1 and Group 2 patients with regard to their postoperative pain/discomfort scores, the need for postoperative narcotic analgesia, or the time required for either group to meet standard discharge criteria. It is concluded that the duration of postoperative analgesia is not impaired by placing the caudal block prior to the start of a brief surgical procedure.