Timing of Preoperative Antibiotic Prophylaxis and Surgical Site Infection: TAPAS, An Observational Cohort Study.

OBJECTIVE: To test the hypothesis that surgical site infection (SSI) risk differs, after administration of surgical antibiotic prophylaxis (SAP) within 60-30 or 30-0 minutes before incision. BACKGROUND: The importance of appropriate timing of SAP before surgery has long been recognized. However, available evidence is contradictive on the best timing within a 60-0 minutes time interval before incision. Here, we aim to evaluate previous contradictions with a carefully designed observational cohort. METHODS: An observational cohort study was conducted in a Dutch tertiary referral center. For 2 years, consecutive patients with SAP indication undergoing general, orthopedic, or gynecologic surgery were followed for the occurrence of superficial and deep SSI as defined by the Center of Disease Control and Prevention. The association between timing of SAP and SSI was assessed using multivariable logistic regression. RESULTS: After 3001 surgical procedures, 161 SSIs were detected. In 87% of the procedures, SAP was administered within 60 minutes before incision. Only antibiotics with short infusion time were used. Multivariable logistic regression indicated there was no conclusive evidence of a difference in SSI risk after SAP administration 60-30 minutes or 30-0 minutes before incision [odds ratio: 0.82; 95% confidence interval (0.57-1.19)]. CONCLUSIONS: For SAP with short infusion time no clear superior timing interval within the 60-minute interval before incision could be identified in this cohort. We were unable to reproduce differences in SSI risk found in earlier studies.