A Single-Centre Retrospective Study on the Impact of Reducing Surgical Prophylaxis from 48 Hours to 24 Hours in Cardiothoracic Surgery

Introduction: In November 2016, surgical antibiotic prophylaxis (SAP) guidelines for cardiothoracic surgeries at the authors’ centre were updated. SAP was reduced from 48 to 24 hours, and dual cover with vancomycin and cefazolin instead of vancomycin monotherapy was recommended for patients colonised with methicillin-resistant Staphylococcus aureus. This study was conducted to review compliance to the updated guidelines, and compare the incidence of surgical site infections (SSI). Methods: A list of patients undergoing sternotomy in National Heart Centre, Singapore, from March 2016 to February 2019 was extracted from the hospital’s electronic database; every fourth patient was included in the analysis. The patients were divided into three groups: Group 1 (before guideline revision, March–October 2016), Group 2 (post-guideline implementation, July 2017–May 2018), and Group 3 (July 2018–February 2019). Compliance to guidelines, incidence, and epidemiology of SSIs within 90 days of surgery were evaluated. Results: 509 patients (Group 1: 149; Group 2: 184; Group 3: 176) were included. There was appropriate selection and timely administration of SAP across all three groups. Post-guideline implementation, the proportion of patients on SAP for >24 hours decreased from 149 (100%) in Group 1 to 55 (29.9%), and 67 (38.1%) in Group 2 and 3, respectively (p <0.001). Despite the reduction in SAP duration, SSI rates remained stable: 4.7%, 3.3%, and 5.1% in Group 1, 2, and 3, respectively (p=0.662). Conclusion: Guideline implementation significantly reduced SAP duration in the authors’ cardiothoracic surgeries, with no increase in SSIs. Continual feedback to ensure sustained compliance may be necessary.