Reducing Surgical Site Infections With Silver Impregnated Dressings in Lower Extremity Bypass Patients.

Abstract

Introduction: Surgical site infection (SSI) after lower extremity (LE) bypass surgery is associated with longer length of stay, higher hospital cost, increased morbidity, and even graft loss. Silver impregnated dressings have been used by other surgical subspecialties to decrease SSI with reported success. The National Surgical Quality Improvement Program (NSQIP) published a national expected rate of 7.9% for SSI after open LE bypass surgery in 2018. Our institutional SSI rate in 2018 was 12.8%. In order to reduce this rate, we transitioned to silver impregnated dressings for all LE bypass procedures and studied any subsequent changes in rates of SSI.

Methods: We used NSQIP data to retrospectively study two consecutive cohorts of vascular surgery patients at a single institution who underwent LE bypasses. Inclusion criteria were open infrainguinal LE bypass patients who were selected via Current Procedural Terminology codes. Patients in 2019 who underwent LE bypass received dry sterile dressing (DSD) postoperatively. Patients in 2020 who underwent LE bypass were treated with silver impregnated dressings postoperatively. NSQIP criteria were used to determine if patients in both cohorts developed SSIs within 30 d of surgery. Fischer's exact and Χ2 test were used to compare groups before and after the intervention. Placement of silver dressings in the intervention cohort was confirmed using review of the medical chart and operative billing reports.

Results: A total of 282 patients who underwent LE bypass in 2019 and 2020 met inclusion criteria. The standard of care cohort had 168 patients with DSD, while the cohort after intervention had 114 patients with silver impregnated dressings. The groups were similar in terms of demographics and comorbidities (Table 1). There was a statistically significant reduction in superficial SSI in the silver dressing group compared to the DSD group (9.6% versus 20.8%, P = 0.014, Table 2). There was a 63% compliance with silver dressing placement in the intervention group. This subset of patients with confirmed dressing placement was similar in terms of demographics and comorbidities (Table 3). Superficial SSI in this patient cohort was decreased from 20.8 to 12.5% (P = 0.15, Table 4). There was no observed difference in deep or organ space infections, wound dehiscence, readmission, and return to operating room between both groups.

Conclusions: This study demonstrated a statistically significant reduction in the rate of superficial SSI in patients undergoing open LE bypass with the use of a silver impregnated dressing when compared to a sterile gauze dressing. Although our study does not demonstrate a causal relationship, this relatively inexpensive and low-risk intervention's association with a significant decrease in an otherwise very serious postoperative complication argues for a change in clinical practice or prospective confirmatory studies to optimize patient outcomes after LE bypass.