significance of timing of administration of antibiotic as prophylaxis during appendectomy

ABSTRACT

In prospective study involving 132 emergency appendicectomies, the use of cephradine [velosef] and metronidazole [Flagyl] was assessed. Patients were randomized into three groups, to receive a single dose of either cephradine 2 g i.v. alone, metronidazole 1 g orally alone; or both antibiotics of the same doses with the premedication [as prophylaxis] and the different times of intake being recorded. Serum drug levels were measured and peritoneal swabs taken. Wounds were inspected regularly for signs of sepsis and patients were closely questioned at follow-up. Twenty three patients were excluded [1 of severe mental and physcial retardation, 5 misdiagnosis, 2 protocol violation, 5 normal and 10 perforated]. This left [109] cases, 34 in group one, 36 in group two and 39 in group three. 6 wound infections occurred [5.5%], represented as 1 in group one [2.94%], 3 in group two [8.33%] and 2 in group three [5.13%]. There was no great difference between each of the three groups, indicating that there is no advantage in combining these antibiotics. Cephradine appears to have sufficient activity both against aerobic and anaerobic organisms to reduce the wound infection rate to a low level. Timing of administration is particularly important for adequate serum drug levels to be present in over 90% of patients at the time of surgery. One must operate within 45 minutes if intravenous cephradine is used and wait at least two and a half hours if oral metroindazole is used. 2 of the 6 infections were deemed preventable on the basis of drug levels