[Perioperative antibiotic prophylaxis in obesity].

Background: In terms of perioperative infections, arthroplasty for obese patients represents a high-risk procedure. Correct antibiotic prophylaxis is a central pillar of infection prophylaxis. Studies showed increased infection rates if an antibiotic other than cefazolin was administered for prophylaxis. In patients with anamnestic penicillin allergy, an existing allergy is extremely rare, and the presence of cross-allergies to cephalosporins is similarly rare. Consequently, every effort should be made to administer a first- or second generation cephalosporin such as cefazolin.

Dosage: Whether the dosage of antibiotic prophylaxis should be adjusted to the body weight remains unclear due to the limited data available: case series showed increased infection rates when cefazolin was underdosed and recommended increasing the dose to 3 g if the body weight exceeds 120 kg. However, no studies with a higher level of evidence exist. Published studies on the effective antibiotic levels in the tissue remain contradictory with regard to possible weight-dependent dose adjustments. Similarly, there is insufficient data on whether local intraoperative antibiotic prophylaxis may be useful in obese patients. By contrast, there is no evidence for a positive benefit of double prophylaxis with two different antibiotics or prolonged postoperative antibiotic prophylaxis in obesity.

Conclusion: In summary, the data on antibiotic prophylaxis is generally insufficient, especially when focussing on possible dose adjustments in obesity. The well-timed administration of a cephalosporin such as cefazolin represents the golden standard in orthopedics and trauma surgery. A possible dose adjustment to 3 g for a body weight over 120 kg appears reasonable considering the low costs and the broad therapeutic window and is therefore recommended in the current AWMF S3 guideline.