Analgesia following appendicectomy--the value of peritoneal bupivacaine.

Purpose: Peritoneal inflammation is an important feature in many patients presenting with appendicitis. The contribution of peritoneal nerve fibres to pain experienced after appendicectomy has received little attention.
Method: In this prospective double blind randomized study a consecutive series of 60 patients undergoing appendicectomy for suspected appendicitis were enrolled. A dose of 1.5 mg.kg-1 bupivacaine 0.5% was used. Group one patients received the entire dose of bupivacaine subcutaneously. Group two patients received half the dose subcutaneously (s.c.) and half the dose to the peritoneum. Pain scores were assessed pre-operatively and at 30 min, 12 and 24 hr post-operatively using a visual analogue scale. Time to first analgesia and total analgesia requirements in the first 24 hr were recorded.
Results: The patients receiving the s.c. combined with peritoneal bupivacaine had a lower pain score 30 min post-operatively (32 +/- 2 vs 54 +/- 4; P < 0.0001), a longer time to first analgesia (248 +/- 20 vs 164 +/- 17 min; P = 0.002) as well as lower opioid (68 +/- 5 vs 100 +/- 7 mg; P = 0.0002) and non steroidal analgesic requirements (65 +/- 6 vs 96 +/- 6 mg; P = 0.007) in the first 24 hr post-operatively.
Conclusion: A combination of s.c. and peritoneal infiltration with bupivacaine is superior to skin infiltration alone in the relief of pain post appendicectomy.