Effect of using silver nylon dressings to prevent superficial surgical site infection after cesarean delivery: a randomized clinical trial

Background Surgical site infections are associated with significant healthcare cost and burden. Silver-impregnated dressings have been associated with a decrease in surgical site infections in select populations, but it is unknown whether the benefit can be observed after cesarean deliveries. Objective We sought to evaluate the impact of silver nylon dressings in reducing superficial surgical site infections after cesarean delivery. Materials and Methods A blinded randomized clinical trial of women undergoing scheduled or unscheduled cesarean delivery at a single site was conducted. Women were recruited for participation from September 2013 to June 2016. Women with vertical skin incisions were excluded. Enrolled participants were randomized to silver nylon dressing or an identical-appearing gauze wound dressing. Wounds were evaluated in the outpatient office at 1 week and 6 weeks after delivery. The primary outcome was superficial surgical site infection as defined by Centers for Disease Control criteria at any time within the first 6 weeks after cesarean delivery. A sample size of 330 per group (n = 660) was planned to compare the 2 arms. Data were analyzed using the χ 2 , Fisher exact test, Student t test, Mann−Whitney U test, and logistic regression where appropriate, and a value of P Results Among the 657 participants, overall, the primary outcome was similar between the 2 groups (4.6% in the silver nylon group vs 4.2% in the gauze group, P  = .96). Women allocated to silver nylon, when compared to those who were allocated to gauze, had similar rates of superficial surgical site infection within 1 week (1.2% vs 0.9%) and within 6 weeks ( 4.6% vs 4.2%) after delivery ( P  >.99). The 2 groups were similar in age (30.9 ± 5.6 vs 31.0 ± 5.5 years, P  = .95), body mass index (36.2 ± 8.7 vs 35.3 ± 8.2 kg/m 2 , P  = .19), pregestational diabetes (6.2% vs 3.4%, P  = .14), gestational diabetes (7.9% vs 7.3%, P  = .88), cesarean delivery after labor (31.9% vs 31.1%, P  = .86), presence of chorioamnionitis (5.2% vs 2.1% P  = .06), and operative time (56.4 ± 20.6 vs 55.9 ± 17 minutes, P  = .69). After adjusting for clinical and sociodemographic confounding variables, current smoking (adjusted odds ratio, 4.9; 95% confidence interval, 1.8−13.4) body mass index ≥40 kg/m 2 (adjusted odds ratio, 3.08; 95% confidence interval, 1.3−6.8), and surgery length (minutes) (adjusted odds ratio, 1.02; 95% confidence interval, 1.002−1.04), but not use of gauze dressing, were associated with superficial surgical site infections. Conclusion Among women undergoing cesarean delivery, silver nylon dressing was not more effective than gauze in reducing the risk of superficial surgical site infections.