Serum Concentration of CEFOxitin Used for Antibiotic Prophylaxis in Obese Patients Undergoing BARiatric Surgery

Obesity is a pandemic problem in modern societies. Bariatric surgery (gastric by-pass and sleeve gastrectomy) has emerged as an efficient treatment to reduce morbidity and mortality related to obesity. Obesity and bariatric surgery are known to be risk factors of surgical site infections (SSI). The occurrence of SSI increases health cost and the duration of hospitalization. However, an appropriate antibiotic prophylaxis has been shown to reduce SSI. As recommended by several national societies, the antibiotic prophylaxis dose should be increased in the severely obese population. However, this recommendation lies on a low level of evidence. Besides, great disparities regarding obese patient antibiotic prophylaxis exist between countries and adequate doses are still not clearly defined. In France, for instance, the intravenous second generation cephalosporin CEFOXITIN is used for antibiotic prophylaxis in bariatric surgery at the initial loading dose of 4g (2-fold that of non-obese population) at the beginning of surgery. Obese patients have increased risk of under-dosage due to modification of their pharmacokinetics (fat/lean mass, distribution volume, renal clearance, etc.). Only few studies, all investigating a low amount of patients, evaluated the appropriateness of intraoperative antibiotic prophylaxis dosage of different betalactam and cephalosporin in the obese population. This population was more likely to be under-dosed. The aim of this study is to analyse the appropriateness of the reference dose of intravenous Cefoxitin used as antibiotic prophylaxis in severely obese patients undergoing bariatric surgery. This will be a 2-year prospective monocentric study held in the University Hospital of Nancy, France. A large group of obese patients (\~300) will be included. Serial serum concentration measurements of Cefoxitin will be performed before, during, and at skin closure of the bariatric surgery. This study will give insights in pharmacokinetics of the antib