The effects of wound infiltration with bupivacaine versus saline on postoperative pain and opioid requirements after herniorrhaphy

Abstract

In a prospective, double-blind, placebo-controlled study, twenty-eight healthy, male patients, aged 20-69 years, scheduled for unilateral elective inguinal herniorrhaphy ad modum Bassini were randomized to receive postoperative infiltration of the surgical wound with either bupivacaine 0.25%, or isotonic saline. General anaesthesia was induced with thiopentone 3-5 mg.kg-1 and alfentanyl 10 micrograms.kg-1, and maintained with alfentanyl 5 micrograms.kg-1 15 min and N2O/O2. After herniorrhaphy, the internal fascia was infiltrated with bupivacaine 0.25% or saline, 10 ml. After closure of the external fascia, the subcutaneous tissue was infiltrated with bupivacaine 0.25% or saline, 15 ml on both sides of the surgical wound. Pain at rest, during mobilisation and during cough was significantly decreased in patients receiving bupivacaine compared to placebo. Median time to first request for morphine was increased from 25 min to 135 min, and the consumption of supplementary morphine during the 24 h study period reduced from four to two doses of 0.1 mg.kg-1 iv or 0.125 mg.kg-1 im, in patients who received bupivacaine compared to placebo.