Continuous Intraoperative Cefazolin Infusion May Reduce Surgical Site Infections during Cardiac Surgical Procedures: A Propensity-Matched Analysis

Objectives The authors sought to determine whether an institutional transition from intermittent to continuous dosing of intraoperative antibiotics in cardiac surgery affected surgical site infection (SSI) outcomes. Design A retrospective chart review utilizing propensity matching. Setting A single academic, tertiary care hospital. Participants One thousand one hundred seventy-nine patients undergoing coronary artery bypass grafting (CABG) and/or cardiac valvular surgery between April 2013 and November 2014 who received perioperative cefazolin. Interventions By method of cefazolin administration, patients were divided into an "intermittent-dosing" (ID) group and a "continuous-infusion" (CI) group. Measurements and Main Results Of the 1,179 patients who underwent cardiac surgery during the study period, 1:1 propensity score matching yielded 399 patients in each group. Rates of diabetes (33.6% ID v 33.8% CI, p = 0.94), coronary artery bypass (62.3% v 61.4%, p = 0.66), and bilateral internal mammary artery harvesting (6.0% v 8.3%, p = 0.22) were similar between groups. SSIs occurred in more ID patients than CI patients (2.3% v 0.5%, p = 0.03). This difference was driven by decreases in extremity and conduit harvest site SSIs (1.8% v 0.3%, p = 0.03), as there were no episodes of mediastinitis, and superficial sternal SSI rates did not differ (0.5% v 0.3%, p = 0.56). There also were significantly fewer episodes of pneumonia in the CI group (6.0% v 2.3%, p = 0.008). Intensive care unit and total lengths of stay did not differ. Thirty-day mortality was 2.8% in both groups (p = 1.00). Conclusions As compared to ID regimens, CI cefazolin infusion may reduce post-cardiac surgery infectious complications. Further study in larger patient populations is needed.