Optimal Cefazolin Prophylactic Dosing for Bariatric Surgery: No Need for Higher Doses or Intraoperative Redosing.

Abstract

The goal of this pharmacokinetic (PK) study was to evaluate whether a single 2-g prophylactic dose of cefazolin given (IV) bolus provides effective protective cefazolin levels for prophylaxis against methicillin-sensitive S. aureus (MSSA), the primary skin pathogen in bariatric surgery. Thirty-seven patients having gastric bypass or sleeve gastrectomy received cefazolin 2-g preoperative prophylaxis. Serum, subcutaneous adipose tissue, and deep peri-gastric adipose tissue specimens were collected at incision and before skin closure. Cefazolin concentrations in serum and adipose tissue were determined by high-performance liquid chromatography. Penetration of cefazolin, a water soluble antibiotic, into adipose tissue was only 6-8% of simultaneous serum levels. However, cefazolin tissue concentrations in all adipose tissue specimens, exceeded mean MIC for MSSA. Prophylactic cefazolin, given as a single 2g (IV bolus 3-5min before skin incision) was more than adequate in providing protective cefazolin levels for the duration of bariatric surgery. Cefazolin 2g (IV dose bolus given just before skin incision) achieves protective adipose tissue levels (> MIC of MSSA) for the duration (usually < 4h) of bariatric surgical procedures. In this study, cefazolin 2g (IV bolus) provided protective adipose tissue levels for 4.8h. Since cefazolin is a water soluble antibiotic (V d=0.2L/Kg), penetration into adipose tissue is not V d not dose-dependent. Extremely high-dosed cefazolin, i.e., 3 or 4g is excessive and unnecessary for bariatric surgery prophylaxis. A single cefazolin 2 g preoperative dose also eliminates the need for intraoperative redosing at 4h.