Negative pressure wound therapy (NPWT), also known as topical negative pressure, sub-atmospheric pressure or vacuum sealing technique, has become a topic of much interest in the area of acute and chronic wound healing. Particularly in the diabetic population, where chronic wounds run rampant, this technology has been explored as a potentially promising therapy.
NPWT is just one of several technological advances in wound care therapy that has emerged in the past several decades. This list also includes bioengineered skin equivalents, bone marrow-derived stem cell therapy, and growth factor therapy. However, the science behind Negative Pressure Wound Therapy is quite interesting.
The vacuum sealing technique involves placement of a special device, sometimes referred to as a wound-vac, on the chronic or acute wound. This device consists of a foam or gauze dressing applied directly to the wound, then sealed tight with a clear, plastic-wrap-like dressing. The dressing is then attached to an electronic device that creates a negative pressure in the newly created seal, similar to a vacuum. This negative pressure ranges anywhere from 50-175 mmHg.
The system created turns an open wound into a controlled, closed wound while removing cellular debris and excess fluid from the wound. This allows the wound to be well-controlled in terms of exudate management. Granulation tissue, the tissue that indicates the ability for the wound to heal, is stimulated to generate within the wound. There is also a decrease in the bacterial load of the wound, reducing the incidence of infection, as well as increased blood flow to the wound.
Published case-studies and small cohort studies have shown negative pressure wound therapy to be effective in the treatment of diabetic foot ulcers. However, a Cochrane review pointed to the fact these trials consisted of too few enrolled subjects to be considered significant evidence to support the use of wound-vacs. However, the growing popularity of the device may lead to more extensive research in the area, as well as better designed studies.
Another area of concern for the use of negative pressure wound therapy is the cost associated with its use. However, several studies have looked at the cost-effectiveness of NPWT, and have found that the decrease in staff required for dressing changes not only balances, but exceeds the cost-effectiveness of standard wound care therapy. Because the NPWT dressings only need to be changed after 48-72 hours, there is less maintenance required for the wound. Therefore, the staff demands are decreased in the management of chronic wounds using NPWT.
Negative pressure wound therapy remains a promising choice for the treatment of diabetic foot ulcerations. The diabetic population is particularly prone to chronic wounds, and NPWT may be a useful technology.
