Design: Retrospective Cohort Study

Setting: Academic safety net hospital

Patients or Participants: Patients undergoing class I laparoscopic or open surgery from 2013 to 2017. This captures the transition to near universal adoption of preoperative antibiotics for these surgeries starting in 2016.

Interventions: Antibiotics (mainly cefazolin) were administered to nearly all patients undergoing surgery starting 2016.

Measurements and Main Results:

510 patients were included: 333 pre-intervention, and 177 post-intervention. 35.4% (118/333) of patients received antibiotics in the pre-intervention group compared to 93.2% (165/177) post-intervention (P=0.001). The primary outcome was incidence of SSI, defined by CDC guidelines. There was no difference in BMI or diabetes prevalence between the groups. The overall incidence of SSI decreased from 9.2% (21/227) in the group that did not receive antibiotics to 4.9% (14/283) in the group that did, but this was not statistically significant (OR 0.511, 95% CI 0.25-1.03, p= 0.06). For patients undergoing an open procedure, there was a statistically significant decrease in SSI rate from 17.4% (12/69) to 6.3% (7/112) in those receiving antibiotics (OR 0.317, 95% CI 0.12-0.85, p=0.022). This held true when adjusting for age, surgical time, EBL, ASA class, and malignancy (aOR 0.225, 95% CI 0.071-0.711, p=0.011). The incidence of SSI in laparoscopic procedures decreased from 5.6% (9/158) to 4.1% (7/171), but this was not statistically significant (aOR 0.633, 95% CI 0.219-1.835, p=0.400).

Conclusion:

There is limited literature on SSI prevention and preoperative antibiotic use in class I surgeries. This study demonstrates antibiotics in clean procedures did not decrease SSI rates, mainly driven by lack of benefit in laparoscopic procedures. However, antibiotics in open procedures did show a lower rate of SSI.