Objective

Our objective was to determine the impact of total preincision infusion time on surgical site infections (SSIs) and establish an optimal time threshold for subsequent prospective study.

Background

SSIs remain a major cause of morbidity. Although regulated, the total time of infusion of preincision antibiotics varies widely. Impact of infusion time on SSI risk is poorly understood.

Methods

All consecutive patients (n = 46,791) undergoing inpatient surgical intervention were retrospectively enrolled (2014-2015) and monitored for 1 year. Primary outcomes: the presence of SSI infection as predicted by reduced preoperative antibiotic infusion time.

Secondary outcomes

preintervention compliance, the impact of a quality improvement algorithm to optimize infusion time compliance. Multivariate logistic regression of the retrospective cohort demonstrated predictors of infection. Receiver-operating characteristic analysis demonstrated the timing threshold predictive of infection. Cost impact of avoidable infections was analyzed.

Results

Only 36.1% of patients received preincision infusion of vancomycin in compliance with national and institutional standards (60-120 min). Cephalosporin infusion times were 53 times more likely to be compliant [odds ratio (OR) 53.33, P < 0.001]. Vancomycin infusion times that were not compliant with national standards (less than standard 60-120 min) did not predict infection. However, significantly noncompliant, reduced preincision infusion time, significantly predicted SSI (<24.6 min infusion, AUC = 0.762). Vancomycin infusion, initiated too close to surgical incision, predicted increased SSI (OR = 4.281, P < 0.001). Implementation of an algorithm to improve infusion time, but not powered to demonstrate infection /reduction, improved vancomycin infusion start time (257% improvement, P < 0.001) and eliminated high-risk infusions (sub-24.6 min).

Conclusions

Initially, vancomycin infusion rarely met national guidelines; however, minimal compliance breach was not associated with SSI implications. The retrospective data here suggest a critical infusion time for infection reduction (24.6 min before incision). Prospective implementation of an algorithm led to 100% compliance. These data suggest that vancomycin administration timing should be studied prospectively.