A Practice Change to Eliminate Prophylactic Antibiotics for Elective Percutaneous Nephrostomy Tube Exchanges in Low-Risk Outpatients: A Retrospective Review on Risk for Infection

Abstract

The purpose of this project was to determine if evidence-based practice change related to antibiotic administration criteria for outpatients receiving percutaneous nephrostomy tube exchanges implemented by a medical center's Vascular and Interventional Radiology department impacted hospital admission rates for infection in these patients. The 2017 practice change was based on 2010 guidelines from the Society of Interventional Radiology (SIR), stating that outpatients with a low risk of acquiring infection did not need to receive a perioperative antibiotic, as evidence has shown prophylactic therapy has no significant effect on infection rates for this population. Using a retrospective review design, 1 year of data before and after the practice change were collected and analyzed using the repeated measures generalized estimating equation (GEE) model with a binomial output by Liang & Zeger. Fisher's exact test was used to evaluate demographic variables by level of risk of infection. Data included 493 procedural events for 126 outpatients. The mean number of events per patient was 3.91 (SD: 4.15; median: 2; interquartile range: 3). Admission and infection criteria within thirty days of the event and infection risk factors were collected for each patient. Age, sex, and race were the variables that had a significant relationship with risk level of infection. Due to sample size, the GEE model could not be run using risk level (high/low) to predict admissions before or after the practice change. The relationship between the number of risk factors (0-5) and the odds of admission for infection was the same regardless of the practice change (before: odds ratio [OR] = 2.17, 95% confidence interval [CI] = 1.19-3.95; after: OR = 1.9, 95% CI = 1.12-3.22, pinteraction = .67). For every increase in a patient's number of risk factors, the odds of developing an infection would be expected to increase by almost 90% (OR = 1.9, 95% CI = 1.27-2.84). Although it was not possible to determine efficacy of the practice change, the predictive analysis indicated that risk level is a significant predictor of admission for infection regardless of antibiotic therapy. The results suggest that demographic indicators should be considered when determining appropriate therapies for this procedure; however, research studies should evaluate this relationship with larger samples to design specific recommendations. Our project results support the 2010 SIR antibiotic prophylaxis guidelines and their more recently updated antibiotic parameter guidelines from 2018.