Cefazolin tissue concentrations with a prophylactic dose administered before sleeve gastrectomy in obese patients: a single centre study in 116 patients.

Abstract

In obese patients undergoing sleeve gastrectomy, the blood and fatty-tissue concentrations of cefazolin required for adequate antibiotic prophylaxis are uncertain. This was a single centre prospective study in obese (Group A: 40≤ BMI ≤50 kg m^-2) and severely obese (Group B: 50< BMI ≤65 kg m^-2) patients undergoing bariatric surgery. Blood and fatty-tissue samples were collected after a cefazolin 4 g i.v. injection. The primary aim was to compare cefazolin concentrations in subcutaneous fatty tissue with a targeted tissue concentration of 4 μg g^-1 according to Staphylococcus aureus resistance breakpoint. One hundred and sixteen patients were included: 79 in Group A and 37 in Group B. At the beginning of the surgery, cefazolin concentration in subcutaneous fatty tissue was 12.2 (5.4) μg g^-1 in Group A and 12 (6.1) μg g^-1 in Group B (P=0.7). At the end, cefazolin concentrations in subcutaneous fatty tissue were 9.0 (4.9) and 7.8 (4.2) μg g^-1 in Groups A and B, respectively (P=0.2). The plasma concentration of free cefazolin during surgery was higher in Group A than in Group B (P<0.0001). Fatty-tissue concentrations of 95% and 83% patients in Groups A and B, respectively, were above S. aureus resistance breakpoint. After a 4 g dose, the concentrations of cefazolin in fatty tissue were above the 4 μg g^-1 tissue concentration target, providing adequate antibiotic tissue concentrations during bariatric surgery. As cefazolin concentration in fatty tissue is a surrogate endpoint, the results should be considered in conjunction with the results on free cefazolin concentrations in subcutaneous tissue. NCT01537380.