Association between Pre-Operative Cefazolin Dose and Surgical Site Infection in Obese Patients

Area of Science:

• Infectious Disease
• Surgical Prophylaxis
• Pharmacokinetics

Background:

• Cefazolin serum concentrations decrease with increasing body mass.
• National guidelines suggest a 3-gram cefazolin dose for patients ≥120 kg, based on pharmacokinetics, not outcomes.
• The efficacy of standard vs. higher cefazolin doses in obese patients requires outcome-based evaluation.

Purpose of the Study:

• To evaluate the efficacy of 2-gram vs. 3-gram pre-operative cefazolin doses in preventing surgical site infections (SSIs).
• To compare SSI rates in obese surgical patients (≥100 kg) receiving different cefazolin prophylaxis doses.

Main Methods:

• Retrospective review of 436 adult patients (≥100 kg) who received cefazolin prophylaxis.
• Exclusion of patients with known infections or inappropriate prophylaxis.
• Identification of SSIs through medical records and CDC criteria, with up to 90-day follow-up.

Main Results:

• No significant difference in SSI rates between the 2-gram (7.2%) and 3-gram (7.4%) cefazolin groups (OR 0.98, p=0.95).
• Adjusted logistic regression analysis also showed no difference in SSI rates (OR 0.87).
• Similar mean follow-up duration (77 days) for both groups.

Conclusions:

• A 2-gram pre-operative cefazolin dose is as effective as a 3-gram dose in preventing SSIs for obese surgical patients (≥100 kg).
• Current guidelines recommending higher doses based solely on pharmacokinetics may not be necessary for SSI prevention in this population.