A retrospective case-control study of a cluster of surgical site infections after coronary artery bypass grafting at a tertiary medical center.

Objective: To investigate a cluster of surgical site infections (SSIs) in patients who underwent coronary artery bypass graft (CABG) procedures, identify risk factors for infection, and implement measures to prevent new cases.

Design: The investigation comprised a retrospective case-control study and an observational review of infection control practices between the fall of 2018 and 2019 (study period).

Setting: Tertiary care medical center in Florida, USA.

Patients: Patients who acquired an SSI following CABG during the study period were defined as case-patients. Control-patients were randomly selected patients who did not acquire a post-CABG SSI.

Methods: We recorded clinical and epidemiologic details on a standardized form and analyzed data with SAS statistical software. Odds ratios and 95% confidence intervals were calculated.

Results: Seven patients met the case definition and 21 control-patients were identified. While multiple variables were significant on univariate analysis, after controlling for confounding using multivariate analysis/logistic regression, only lower age (P < 0.0001) and meeting the requirements for appropriate perioperative temperature management (SCIP measure 10) (P = 0.01) were identified as independent risk factors for SSI. Per observational review, measures to reduce operating room traffic and limit door opening/closing were implemented and wound vacuum-assisted closure (VAC) use was phased out. Our institutional SSI rate returned to baseline and no additional clusters were seen in the following three years.

Conclusions: Multiple potential risk factors exist for SSI after coronary artery bypass grafting. At our institution, minimizing operating room traffic and reducing wound VAC use may have successfully addressed these healthcare-associated infections.