Cath Lab Digest

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Index: Ostomy Wound Manage. 2008;54(12):36-46.

Wound closure using topical negative pressure (TNP) has been reported to be effective, but equipment costs can be prohibitive in resource-challenged countries. Because nonhealing wounds are exceedingly common in developing countries such as India, the ability to optimize wound care with limited resources is very important. To investigate the feasibility and efficacy of providing TNP in an Indian medical referral center, a randomized controlled trial comparing a locally constructed TNP device (treatment) to wet-to-dry gauze dressings (control) was conducted. Eligible study participants (N = 48) were recruited from the inpatient wards. Wound etiologies included diabetic foot ulcers (15), pressure ulcers (11), cellulitis/fasciitis (11), and “other” (11). Following enrollment, wound size was assessed using computer-aided measurements of digital photographs and block-randomized to the study arms using a concealed allocation table. Wounds in both treatment groups were débrided before dressing application and patients were followed until wound closure or being lost to follow-up for an average of 26.3 days (± 18.5) in the control and 33.1 days (± 37.3) in the treatment group. No statistically significant differences in time to closure between the two treatment groups were observed except in a subset analysis of pressure ulcers (mean 10 ± 7.11 days for treatment and 27 ± 10.6 days in control group, P = 0.05). Direct costs to close a pressure ulcer also were lower in the TNP than in the control group. A review of the literature suggests the outcomes obtained using a locally constructed TNP device are similar to those obtained using commercially available devices. As a result of this study, a dedicated tissue viability team has been established to identify wounds suitable for TNP, oversee treatment, monitor the need for surgical débridement, and employ wound healing principles and technology appropriately. These results suggest that inexpensive materials can be utilized for TNP wound closure in a developing country.

KEYWORDS: wounds, topical negative pressure, developing world, randomized controlled trial, South India

   Topical negative pressure (TNP) as a wound treatment utilizes a combination of mechanical force and controlled drainage in a closed environment to promote healing.^1,2 Dressings for TNP involve packing material, tubing to create negative pressure at the wound site, a suction pump, an airtight drape, and an effluent collector. Changes that have been observed in the wound environment exposed to TNP include reduced bacterial load and edema, improved vascularity, increased granulation tissue through mechanical deformation of tissues, skin stretching, and reduced exposure to shear forces on granulation tissue in the wound bed through frequent removal or disruption of the dressing. ^2,3

   Originally described in the 1980s as a clinical innovation to enhance débridement of infected wounds, the initial TNP prototype was developed into a method of wound closure by several contemporary surgical groups. ^4-7 Based on these designs, commercial systems were constructed using medical-grade foam and pressure sensors. ⁸ Reductions in healing time and wound size of chronic nonhealing wounds and diabetic foot ulcers affected by TNP have been documented in several randomized controlled trials of these systems. ^9-11 Currently, TNP is most often used to close surgical and traumatic wounds and chronic ulcers and to bolster skin grafts. ^2,12 Its role in treating enterocutaneous fistulae and other complex wounds also has been described.