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

"Three blood samples will be collected. These samples are specific for the research, and will be performed on the forearm opposite to the one used for Cefoxitin infusion.~1. Blood sample at the start of surgery (t0): at the end of the Cefoxitin infusion (\~30 min), 1 tube (5 ml) of blood will be withdrawn~2. Blood sample at half way surgery (t1): 1 tube (5 ml) of blood will be withdrawn (if applicable)~3. Blood sample at skin closure (t2): 1 tube (5 ml) of blood will be withdrawn"