Because surgery in obese patients is associated with a high risk of
infection,
gastric bypass procedures offer an excellent opportunity to test the efficacy of prophylactic
antibiotics. Accordingly, a double-blind prospective trial of prophylactic
cefazolin was carried out in 53 consecutive patients who underwent
gastric bypass surgery for
morbid obesity. The patients were randomized to two treatment arms: (1)
cefazolin intravenously, 1 gm 2 hours prior to surgery, at induction of
anesthesia, and then 0.5 gm every 6 hours for 48 hours, or (2) an indistinguishable placebo of 5%
dextrose at identical intervals. Serial cultures were taken at operation and in the postoperative period.
Antibiotic levels of fat were measured by tissue extraction and B. subtilis assay. After surgery, patients were monitored for
infection by clinicians unaware of their random assignment group. The study was terminated and the code broken when it was evident that
wound infections were increased to a statistically significant difference in one arm of the study. The brief perioperative administration of
cefazolin reduced the incidence of
wound infection from 21% to 4% (P less than 0.05) and the incidence of urinary tract and pulmonary
infections from 17% to 0% (P less than 0.05). Tissue levels of
antibiotics confirmed adequate dosages in the test subjects. The advantages of prophylactic administration of
cefazolin for
gastric bypass procedures are clearly demonstrated in this study. This confirms other reports which have shown prophylactic
antibiotics to be useful in a variety of procedures. These studies suggest the need to reconsider the traditional opposition to prophylactic
antibiotics and to determine whether perioperative
antibiotics should be used routinely in all major operations.