Chemoprophylaxis of postoperative infections in colorectal surgery.

Colorectal surgery involves a high risk of postoperative infections. The major risk factors can be reduced by appropriate preparation of the patient for the operation. Mechanical removal of gross faecal material from the bowel, possible before most elective operations, does not sufficiently reduce the incidence of postoperative infections. Prophylactic medication has not yet been widely accepted, although its effectiveness has been confirmed by a number of studies. Preoperative management of patients subjected to colorectal surgery at our institution in the last three years, consisted of mechanical cleansing of the intestinal tract for two days, followed by rapid intravenous administration of gentamicin 80 mg and metronidazole 500 mg in a single dose, 30 min to 1 h before the operation. From 1971 to 1973, the postoperative infection rate in 432 patients submitted to elective colorectal surgery was 29%. During the period 1981-1983, operations of the same kind were performed in 572 patients, the infection rate being 15%. Prophylactic single-dose administration of gentamicin in combination with metronidazole has proved to be very effective in reducing postoperative infections.