Venous leg ulcer management: single use negative pressure wound therapy

Effective negative pressure wound therapy for open wounds: The importance of consistent pressure delivery

Two distinct design concepts exist for single-use negative pressure wound therapy systems: Canister-based versus canisterless. The canister-based technology provides intrinsic stable delivery of the intended negative pressure, because exudate is constantly transferred from the wound into a canister, thereby preventing dressing saturation. In contrast, with a canisterless system, where delivery of the negative pressure depends on continuous evaporation of wound fluids from its dressing, loss of the intended wound-bed pressure may occur due to dressing saturation. To investigate whether these two designs differ in their mechanobiological effect with respect to magnitudes and distributions of tissue strain fields under the absorptive dressing, termed the influence zone, we integrated computational modelling with an animal study. This influence zone must be of biologically influential strain levels and extend sufficiently into the peri-wound for stimulating fibroblasts to migrate and progress the healing. We found that an effective influence zone requires continuous delivery of the intended pressure to the wound-bed. Loss of negative pressure at the wound-bed below 40 mmHg adversely lowered the peri-wound stimulation around a 120 × 70 mm sized wound to less than one-third of the baseline stimulation, and further pressure decreases to 20 mmHg or lower resulted in complete lack of peri-wound mechano-stimulation.

Novel home use of mechanical negative pressure wound therapy in diabetic foot ulcers

OBJECTIVE

Mechanical negative pressure wound therapy is an ultraportable, light weight and disposable single-use device that has been shown to promote wound healing. This study evaluated home use of a mechanically powered negative pressure wound therapy (NPWT) in diabetic foot wounds.

METHODS

Patients underwent revascularisation and/or debridement or amputation before starting mechanical NPWT. Wound outcomes and images of the wounds were recorded at each follow-up visit by the wound nurse. Patients were followed up until wound closure or end of therapy.

RESULTS

A total of 12 patients (each with one wound) were included in the study. Of the 12 wounds, 33.3% (n=4) of wounds achieved primary wound closure while the remaining 66.6% (n=8) of wounds demonstrated a mean wound size reduction of 37.5±0.13%. Of the closed wounds, mean time to healing was 4.75±2.50 weeks. There was 100% limb salvage with no further debridement or amputations, and no 30-day unplanned readmissions. Mean length of hospital stay before starting home NPWT was 9.75±6.31 days. Mean number of NPWT changes was 8.33±2.67 sessions, while mean duration of therapy was 4.0±1.54 weeks. Mean cost of home NWPT therapy was US$1904±731 per patient.

CONCLUSION

The home use of mechanically powered NPWT in diabetic foot wounds demonstrated excellent wound healing rates and 100% limb salvage, with no complications.

Providing cost-effective treatment of hard-to-heal wounds in the community through use of NPWT

OBJECTIVE

The treatment of non-healing wounds accounts for a high proportion of wound care costs. Advanced technology treatments, such as negative pressure wound therapy (NPWT), could be cost-effective if they result in faster healing. The objective of this study is to assess the effect on healing and the cost-effectiveness of a single-use NPWT (i.e PICO by Smith & Nephew) when used on hard-to-heal wounds in a community setting.

METHOD

This was a cohort case study in which wounds were treated with NWPT for 2 weeks. Wounds were assessed every 2-4 weeks to a healed state. The weekly cost of treatment prior to intervention, that is, the products used and nurse time, were compared with treatment costs associated with NWPT and after a return to standard treatment.

RESULTS

The study included 9 patients with leg ulcers or pressure ulcers that had been slow healing or non-healing for at least 6 weeks. While treated with NPWT, the average weekly reduction in wound size was 21%. The wound size achieved with NPWT was reached on average 10 weeks earlier than predicted. The increased healing rate continued after PICO stopped and 5 wounds healed on average 8 weeks later. Frequency of dressing changes fell from 4 times weekly at baseline to 2 times a week with NPWT and to 1.8 after NPWT stopped. Weekly cost of treatment with NPWT was, on average, 1.6 times higher than the baseline, but fell to 3 times less when NPWT stopped owing to the reduction in dressing changes. The amount of change in healing rate was considerably higher than the increase in costs associated with NPWT.

CONCLUSION

NWPT is a cost-effective treatment for hard-to-heal wounds. Wounds decreased in size and healed more quickly under NWPT treatment than under standard treatment. Additional NPWT costs can be quickly offset by faster healing and a shortened treatment period.

Negative-pressure wound therapy for management of diabetic foot wounds: a review of the mechanism of action, clinical applications, and recent developments

Negative-pressure wound therapy (NPWT) plays an important role in the treatment of complex wounds. Its effect on limb salvage in the management of the diabetic foot is well described in the literature. However, a successful outcome in this subgroup of diabetic patients requires a multidisciplinary approach with careful patient selection, appropriate surgical debridement, targeted antibiotic therapy, and optimization of healing markers. Evolving NPWT technology including instillation therapy, nanocrystalline adjuncts, and portable systems can further improve results if used with correct indications. This review article summarizes current knowledge about the role of NPWT in the management of the diabetic foot and its mode of action, clinical applications, and recent developments.