Bupivacaine in caudal anaesthesia for anal surgery.

A study is described of 100 consecutive patients given a caudal block for anal surgery using either 0.25% or 0.5% bupivacaine with adrenaline. The initial success rate was 91%, and a further 8% achieved only a unilateral block. Satisfactory anaesthesia in these cases could be achieved with either a second caudal block or unilateral infiltration of the un-anaesthetized half of the surgical field with lignocaine. Optimal anaesthesia took up to 15 minutes to develop in 90% of the patients, and 20 minutes for all patients. No serious complications were observed. Post-operative analgesia lasted between 10 and 12 h after the block and this compared favourably with the results from two small control groups given either a general anaesthetic or a lignocaine caudal block in which the patients required analgesics 2,5 and 4,5 h respectively from the start of the anaesthetic procedure. In the bupivacaine treated patients there was a significant reduction in the need for post-operative analgesics throughout the whole postoperative period.