Plasma and Tissue Concentration of Cefazolin in Preoperative Prophylaxis in Patients Undergoing Bariatric Surgery

Laval University

Status: Active, not recruiting

Conditions: Bariatric Sleeve Gastrectomy; Cefazolin

Study type: Observational

Funder types: Other

Identifiers

NCT07253805

CER 21626, 2019-3053

Details and patient eligibility

About

This study investigates whether current cefazolin dosing guidelines for obese patients-2 g IV for those <120 kg and 3 g IV for those ≥120 kg-achieve adequate plasma and tissue concentrations (≥8 mg/L) for effective surgical prophylaxis. While several retrospective and prospective studies suggest that a 2 g dose may be sufficient regardless of weight, findings are inconsistent and often rely solely on plasma concentrations. Given that tissue concentration at the site of action is a more relevant pharmacokinetic marker, the study emphasizes the need to measure cefazolin levels in adipose tissue. Previous research using microdialysis has shown reduced tissue distribution in obese patients, potentially warranting higher doses. The study also highlights variability in defining the minimum inhibitory concentration (MIC) required for prophylaxis, noting that 8 mg/L is often considered the threshold for Enterobacteriaceae. Ultimately, the study aims to clarify whether current dosing achieves effective antibiotic levels across different weight categories, with a focus on tissue concentrations.

Enrollment: 70 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Have a BMI ≥ 35 kg/m²
• Undergo bariatric surgery (sleeve gastrectomy) via laparoscopy

Exclusion criteria

• Under 18 years of age
• Weight over 180 kg
• Penicillin allergy
• Pregnant or breastfeeding women
• Chronic kidney disease (eGFR < 60 ml/min according to the Cockcroft-Gault equation)
• Liver cirrhosis
• Intraoperative blood loss ≥ 1 liter

Trial design

70 participants in 2 patient groups

Clindamycin group/control

Description:

A control group of 10 patients undergoing sleeve gastrectomy at the Quebec Heart and Lung Institute, who have not been exposed to cefazolin due to penicillin allergy, will be recruited to validate the analytical method. During surgery, biopsies of adipose and dermal tissue and blood samples will be collected. No other antibiotic or medications will be administered to these patients.

Ancef group

Description:

Sixty patients will be recruited for the study, with 20 patients assigned to each weight category. Recruitment will take place during the preoperative consultation at the bariatric surgery clinic. All patients expressing interest will be included, provided they do not meet any exclusion criteria (convenience sampling). During surgery, biopsies of adipose and dermal tissue and blood samples, will be collected. No additional antibiotics or medications will be administered to these patients.