Evaluation study of the properties of two adhesive foam dressings

A randomised controlled 8-week crossover clinical evaluation of the 3M Coban 2 Layer Compression System versus Profore to evaluate the product performance in patients with venous leg ulcers

This study compared a two-layer (Coban 2 Layer) and a four-layer (Profore) compression bandage system in venous leg ulcer patients. Participants (n = 81) were enrolled into an 8-week, randomised, open-label, ten-centre, crossover clinical trial. The primary endpoint was bandage slippage measured at each dressing change. Secondary endpoints included wound healing, health-related quality of life (HRQoL) and patient preference. Mean slippage estimated from a mixed analysis of variance model (697 visits) was 2.48 cm for the two-layer system and 4.17 cm for the four-layer system (P < 0.001). There were no significant differences in percent of wounds that healed (Fisher's exact test, P = 0.30), in wound area reduction (Wilcoxon rank-sum test, P = 0.88) or in linear healing rate (Wilcoxon rank-sum test, P = 0.94). The HRQoL Physical Symptoms and Daily Living scores were significantly higher with the two-layer system (pooled two-sample t-test, P < 0.05). Patients had a strong preference for the two-layer system (72%) than the four-layer system (22%), with 6% having no preference. In conclusion, the two-layer system exhibited significantly less bandage slippage than the four-layer system. While less bandage slippage did not appear to impact wound healing, there was indication that it may have influenced patient preference in favour of the two-layer system and potentially impacted patients' HRQoL.

Economics of pressure-ulcer care: review of the literature on modern versus traditional dressings

Published evidence suggests that some of the benefits of modern dressings--longer wear times and less frequent dressing changes--make them more cost-effective than traditional gauze dressings in pressure ulcer management.

Dressings for healing venous leg ulcers

BACKGROUND

Venous leg ulcers, sometimes called varicose or stasis ulcers, are a consequence of damage to the valves in the veins of the legs, leading to raised venous pressure. Venous ulcers are characterised by a cyclical pattern of healing and recurrence. The main treatment is the application of compression, either in the form of compression bandages or hosiery. Dressings are usually applied beneath the compression to aid healing, comfort and to control exudate. Wounds heal quicker in a moist environment and dressings are used to absorb excess fluid or retain fluid in an otherwise dry wound in order to achieve a 'moist wound environment'. There are a large number of dressing products and types available. It is unclear whether particular dressings aid healing of leg ulcers.

OBJECTIVES

To assess the effectiveness of wound dressings for the treatment of venous leg ulcers.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Register (April 2006) and CENTRAL (issue 1, 2006) and several other electronic databases (up to April 2005). Manufacturers of dressing products were contacted for unpublished studies.

SELECTION CRITERIA

Randomised controlled trials that evaluated dressings for the treatment of venous leg ulcers. There was no restriction in terms of source, date of publication or language. Ulcer healing was the primary endpoint.

DATA COLLECTION AND ANALYSIS

Data from eligible studies were extracted and summarised using a data extraction sheet by two authors independently.

MAIN RESULTS

42 randomised controlled studies were identified that met the inclusion criteria. The main dressing types that were evaluated were hydrocolloids (n = 23), foams (n = 6), alginates (n = 4), hydrogel dressings (n = 6) and a group of miscellaneous dressings (n = 3). In none of the comparisons was there evidence that any one dressing type was better than others in terms of number of ulcers healed. Current evidence does not suggest that hydrocolloids are more effective than simple low adherent dressings used beneath compression (9 trials; relative risk for healing with hydrocolloid 1.09 (95% CI 0.89 to 1.34)). For other comparisons there was insufficient evidence.

AUTHORS' CONCLUSIONS

The type of dressing applied beneath compression has not been shown to affect ulcer healing. For the majority of dressing types there was insufficient data to allow us to draw strong conclusions except for hydrocolloid compared with a low adherent dressing. The result of the meta-analysis indicate no significant difference in healing rates between hydrocolloid dressings and simple, low-adherent dressings when used beneath compression. Decisions regarding which dressing to apply should be based on local costs of dressings and practitioner or patient preferences.

Evaluating dressing materials for the prevention of shear force in the treatment of pressure ulcers

OBJECTIVE

Shear force is believed to affect pressure ulceration. Therefore, dressing materials that reduce shear force may prevent ulceration and facilitate healing.

METHOD

We measured the following three properties: the coefficient of friction between the outer layer of the dressings and the patient's clothes; the degree of adhesiveness between the inner layer of the dressing and the patient's skin; the transmissibility of shear force of the dressing.

RESULTS

The coefficients of static friction were 1.01 for hydropolymer, 0.72 for hydrofoam and 0.48 for hydrocolloid. Adhesiveness was tested by rolling different sized ball bearings down a slope and over the adhesive lining under both wet and dry conditions. Under dry conditions, the heaviest ball bearing that stopped rolling for five seconds was 111.9g for both hydrofoam and hydrocolloid. Under wet condition, it was 11.9g for hydrofoam and under 1g for hydrocolloid. Tests showed the very low transmissibility (I N buffer) of shear force for hydrofoam, with significant differences between the dressings. Clinical observation has identified good results for hydrofoam when used under highly exuding conditions and for hydrocolloid when used with relatively slight or decreased exudate.

CONCLUSION

Existing dressing materials are being developed and evaluated for wound healing. However, if innovations in the raw materials from which dressings are manufactured could lead to a reduction in shear force and the prevention of pressure ulcers, then dressing materials could be discussed from a viewpoint that is quite different from wound healing.