Negative Pressure Wound Therapy for Abdominal Wounds

There are many treatment options available for abdominal wounds. This commentary will focus on the use of Negative Pressure Wound Therapy (NPWT) for abdominal wounds in response to the article “Negative Pressure Therapy for Laparotomy Wounds—A Word of Caution” by Andrabi and Ahmad in this month’s JWOCN. Negative pressure wound therapy, if used appropriately, has been shown to be beneficial in promoting healing wounds.1,2 The benefits of NPWT therapy over usual dressings are: (1) removal of exudate and bacteria, (2) diminished interstitial pressure, (3) increased blood flow and mitotic activity, and (4) preservation of a moist wound healing environment.2,3 When choosing a treatment for abdominal wounds, the clinician should be prepared to answer multiple pertinent questions (Box 1). A comprehensive assessment of the patient is completed. Past medical and surgical history may reveal conditions that impede healing such as diabetes mellitus or anemia. The patient’s history may identify medications that hinder wound healing such as steroids, immunosuppressants, and chemotherapy agents. When NPWT is considered, the administration of anticoagulants such as warfarin (Coumadin) and heparin must be carefully considered because they may increase the risk of bleeding. Wound homeostasis is imperative and frequent monitoring of activated partial-thromboplastin time (PTT), and/or prothrombin time (PT), with international ratio (INR) levels is necessary. The assessment also incorporates the patient’s nutritional status since poor nutritional intake will decrease healing. The intake of protein is especially important for promoting wound healing.4 Although NPWT has been shown to promote wound closure, it cannot compensate for poor protein levels.2 Therefore, consultation with a dietician and adequate nutritional intake are essential aspects of this comprehensive assessment. Careful inspection of the wound is also completed prior to application of NPWT. Different techniques may be used to protect the underlying tissue and exposed bowel when Vacuum Assisted Closure (VAC) (KCI Inc., San Antonio, TX) is used to deliver NPWT. For example, when the wound involves subcutaneous tissue and muscle GranuFoam (Black) (KCI, Inc., San Antonio, TX) is cut to fit the wound bed. Based on the patient’s pain level a layer of nonadherent dressing can be placed on the wound bed prior to sponge placement. An alternative sponge, VersaFoam (KCI, Inc., San Antonio, TX), is nonadherent and can be used in place of the nonadherent dressing. I have found that application of GranuFoam and a layer of nonabsorbant dressing decreases pain and discomfort during dressing changes (Figures 1 and 2). The type of dressing applied over a mesh graft depends on how much bowel and mesh are exposed in the wound base. The abdominal wound dressing can be used with meshed graft covering the bowel (Figure 3). GranuFoam with a nonadherent dressing can also be used in abdominal wounds covered with meshed grafts (Figure 4). Other types of mesh may be used to cover the bowel and GranuFoam may be placed over these without difficulty (Figure 5). Exposed bowel may be managed with the abdominal wound dressing, which has a fenestrated nonadherent layer with GranuFoam in the center. It is applied directly over the bowel and tucked into the gutter surrounding the bowel. The GranuFoam is placed over the fenestrated nonadherent layer, which fills the remaining defect (Figure 6). Continuous negative pressure is recommended for the first 48 hours of therapy, followed by intermittent negative pressure.5 Intermittent negative pressure is believed to increase granulation tissue formation.6 However, it may not be appropriate for wounds that are painful or produce copious amounts of drainage. Continuous suction will eliminate the pain felt by the patient when the negative pressure is cycled through the off to on phase. Leaking will occur with a highly exudating wound from under the