Reducing Surgical Site Infections with Silver-impregnated Dressings in Lower Extremity Bypass Patients

Abstract

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 LE bypass surgery. In 2018, our institutional SSI rate was 12.8%. To reduce this rate, we transitioned to silver-impregnated dressings for all LE bypass procedures and studied the subsequent impact on SSIs. We used NSQIP data to retrospectively study two consecutive cohorts of vascular surgery patients at a single institution who underwent LE bypasses. Patients in 2019 underwent the standard of care surgery with standard sterile gauze postoperative dressings. Patients in 2020 underwent standard of care surgery and were treated with silver-impregnated dressings. NSQIP criteria were used to determine if patients developed SSIs within 30 days of surgery. The Fischer exact and χ2 tests were used to compare groups before and after the intervention. A total of 282 patients underwent LE bypass in 2019 and 2020. The standard of care cohort had 168 patients with sterile gauze dressings, whereas the cohort after intervention had 114 patients with silver-impregnated dressings. The groups were similar in terms of demographics and comorbidities (Table). When considering all classifications of SSI, there were significantly fewer infections in the silver dressing group compared with the sterile gauze group (9.6 % vs 20.8%; P = .014). There was a non-statistically significant reduction in readmissions and unplanned return to the operating room in the silver dressing group. This study demonstrated a significantly lower rate of SSIs in patients undergoing LE bypass with use of a silver-impregnated dressing when compared with 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.TableDemographic and comorbidity differences between groups of patients who underwent lower extremity (LE) bypass surgery using sterile gauze dressing (2019) and silver-impregnated dressing (2020), and NSQIP-collected outcomes regarding postoperative surgical site infection (SSI), wound dehiscence, unplanned return to operating room, and readmission within 30 daysSterile gauze (n = 168)Silver dressing (n = 114)P-valueMale gender109 (64.8)79 (69.3).5Age, years67.1 (10.8)66.0 (11.2).4Race.7 Asian1 (0.6)2 (1.8) Black or African American25 (14.9)13 (11.4) Unknown11 (6.5)7 (6.1) White131 (78.0)92 (80.7)Emergent surgery10 (5.9)4 (3.5).4Active smoker78 (46.4)52 (45.6).9Diabetes.4 Yes, insulin-dependent47 (28.0)39 (34.2) Yes, non-insulin-dependent32 (19.1)23 (20.2) No89 (53.0)52 (45.6)Hypertension133 (79.2)93 (81.6).6Chronic obstructive pulmonary disease26 (15.5)15 (13.2).6Dialysis10 (5.9)10 (8.8).4Superficial SSI35 (20.8)11 (9.7).014Deep SSI5 (3.0)2 (1.8).7Organ space SSI2 (1.2)6 (5.3).07Wound dehiscence6 (3.6)5 (4.4).8Unplanned return to operating room43 (25.6)32 (28.1).7Readmission39 (23.2)30 (26.3).2Data are presented as mean (standard deviation) or number (%). Open table in a new tab