Prevention of poststernotomy wound infections in obese patients by negative pressure wound therapy

The majority of wound infections after median sternotomy in obese patients are triggered by the breakdown of skin sutures and subsequent seepage of skin flora. The purpose of this study was to evaluate negative pressure wound dressing treatment for the prevention of infection. We hypothesized that negative pressure wound dressing treatment for 6 to 7 days applied immediately after skin closure reduces the numbers of wound infections.

In a prospective study, 150 consecutive obese patients (body mass index ≥ 30) with cardiac surgery performed via median sternotomy were analyzed. In the negative pressure wound dressing treatment group (n = 75), a foam dressing (Prevena, KCI, Wiesbaden, Germany) was placed immediately after skin suturing, and negative pressure of -125 mm Hg was applied for 6 to 7 days. In the control group (n = 75), conventional wound dressings were used. The primary end point was wound infection within 90 days. Mann-Whitney U test and Fisher exact test were used. Freedom from infection was estimated by Kaplan-Meier analysis.

Three of 75 patients (4%) with continuous negative pressure wound dressing treatment had wound infections compared with 12 of 75 patients (16%) with conventional sterile wound dressing (P = .0266; odds ratio, 4.57; 95% confidence interval, 1.23-16.94). Wound infections with Gram-positive skin flora were found in only 1 patient in the negative pressure wound dressing treatment group compared with 10 patients in the control group (P = .0090; odds ratio, 11.39; 95% confidence interval, 1.42-91.36).

Negative pressure wound dressing treatment over clean, closed incisions for the first 6 to 7 postoperative days significantly reduces the incidence of wound infection after median sternotomy in a high-risk group of obese patients.