Dunford (2005) propose that one can think that pressure gradient across soft tissue might lead to the mechanical deformation of cells. Mechanically stretching isolated cells from several organs is referred to as the stimulate cell mitosis, cell proliferation, and angiogenesis. It has therefore been suggested that in using of negative pressure wound healing process is hastened in a similar way. The presumption is that the application of negative pressure disrupts the balance between the extracellular matrix and the intracellular cytoskeleton which as a result leads to the release of various intracellular second messengers.
On the other hand, computer modeling based on histological studies proposes that the pressures used in the wound VAC create tissue strain sufficient for deformation of cells. Even though these cellular changes have not been demonstrated by various researcher and hence there have been no [proof it they can be applied as well in the whole process. The research further suggested that intermittent negative pressure is more effective than continuous negative pressure in stimulating wound therapeutic because continuous pressure leads to less cell buckle.
Negative pressure may directly stimulate wound healing by basically creating a pressure gradient that “pulls” materials or cells from the wound bed or from the surrounding tissues into the wound bed and then into the foam dressing of the wound vac. Several mechanisms have been proposed to explain the positive impacts of this occurrence. Researchers did suggest that a wound VAC might “pull” this extra fluid out of the interstitial spaces, and thus reducing edema and improving nutrient delivery to the healing wound. It has been also demonstrated that the wound VAC reduces edema in and around acute experimental burns in swine but it remains to be demonstrated if these effects occur in human beings also. The latter findings may suggest that the effectiveness of vacuum-assisted closure may not be associated with a reduction in the bio-burden of the wound. This is due to the fact that two studies fluctuate or vary in the frequency of dressing changes, the frequency of dressing change rather than negative pressure.
It has been suggested that the pressure gradient may act by simply pulling or drawing greater numbers of keratinocytes into and across the wound; thereby, increasing the population of cells necessary for wound healing. Negative pressure gradients also may favor the approximation of soft tissue and reduce the likelihood of soft tissue retraction. Also, the simple action of bringing and holding the wound edges closer together would promote wound healing. Again, no evidence is available to support the notion that a wound VAC enhances wound healing by either of these mechanisms.
Vacuum-assisted closure has been available for roughly a decade. A Medline search of materials published between 1996 and May 2006 yielded more than 150 articles written in English that describe wound VAC method and results. Of these publications included animal studies, some were categorized as randomized controlled trials, and the rest categorized as reviews. The remaining were case studies and case series. Negative pressure has been used to treat a broad range of non-healing wounds ranging from chronic wounds such as those mentioned earlier to traumatic wounds, burns and surgical wounds. With few exceptions, the published results suggest that the wound VAC is useful in generating wound closure. Few undesirable effects related to wound VAC use such as dehydration, bleeding, pain, and infection has been reported. Although the available evidence collected from case studies strongly suggests that wound VAC use is effective in promoting wound healing as compared to traditional methods which took much time to heal.
Maylor (2005) argues that in an effort to determine if the wound VAC is more effective than other conventional treatments in the management of chronic wounds. According to a publication of Cochrane review concerning available randomized controlled clinical studies comparing the wound VAC with other wound dressing methods healing period differed. These authors also called for multicenter, well designed, adequately powered, randomized controlled studies to evaluate the relative effectiveness of the wound vac.
The issue concerning relative effectiveness of the wound VAC was revisited in 2004 when available data were reviewed by the Agency for Healthcare Research and Quality (AHRQ). This review was undertaken in an attempt to determine the efficacy of VAC to other correlated methodologies which proved to be lacking evidence. The traditional or the convention method was seen as not applicable due to the fact that the process took so long before the wound could heal completely. Recently, Armstrong and Livery made a report on the use of the wound VAC in healing diabetic foot ulcers in a randomized control trial involving 160 patients with diabetic foot wounds. Patients were treated with the wound VAC or moist wound therapy until the wound closed or for a maximum of 112 days of treatment.
Application of wound VAC was apparently effective as it was used in a broader parameter or vicinity. Various plausible and testable hypotheses through which the devices are used have recorded greater changes in the whole process of wound treatment. It is also evident that the general outcomes when wound VAC is used are generally nominal. Moreover, wound VAC treatment has been primarily been compared to conventional methods of wound dressing, which is a wound covering that can not really provide most favorable healing, and many newer potential methods of wound dressing have not been used. In the process of detecting the differences that are related to this issue render this literature review insufficient. Even though the general concern about this study remains interestingly bias. Successfully, conducting such studies will really be difficult due to varied reasons but the results will provide much needed clinical information relating to optimal wound care. Even though, there are challenges that are associated with wound management this paper have critically evaluated and suggested clinical governance as a way of dealing with this vise. Finally, there is need of developing a way of improving quality of life through employing efficient wound care.
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