Antibiotic prophylaxis in general surgery: a comparison of single-dose intravenous and single-dose intra-incisional cephaloridine.

Four hundred and five consecutive patients undergoing emergency or elective abdominal operations were randomly allocated to receive prophylaxis against wound sepsis by means of a single dose of 1 g cephaloridine either injected intravenously at the start of, or instilled into the incision at the end of, operations. Ten patients died within two weeks without wound sepsis and in the remaining 395 patients there were no significant differences between the two groups in the rates of major (3.5% and 2.1%) or minor (12.4% and 15.5%) wound sepsis. Nutrient broth culture of visceral and parietal swabs during operations enabled a microbiological classification of abdominal operations to be made, the rates of wound sepsis being significantly different among "clean" (1.0%), "potentially contaminated" (8.1%), "lightly contaminated" (19.4%) and "heavily contaminated" (44.6%) operations. This classification by extent of operative contamination makes it possible to standardize the audit of sepsis rates both among surgeons and among hospitals.