Rational use of antibiotic therapy after appendicectomy.

A prospective randomised trial was carried out on 263 patients admitted for appendicectomy. In those patients with normal or inflamed appendix only, wound sepsis occurred in five (5%) of the 96 patients receiving metronidazole compared with seven (7%) of the 91 controls. In patients with gangrenous or perforated appendices, however, 15 of the 32 patients (47%) receiving ampicillin and five (16%) of 31 patients receiving metronidazole developed a wound infection (p less than 0.025). Therapeutic courses of metronidazole significantly reduced wound sepsis rate in those with gangrenous or perforated appendices. Together with another antibiotic it should form part of the management of such patients, but antibiotics are unlikely to reduce further the low rate of wound infection in patients with normal or inflamed appendices.