A Comparison of the In Vitro Physical Performance Characteristics of Silicone Foam Dressings used in Non to Low Exuding Wound Management
Foam dressings are used routinely in the management of medium to highly exuding wounds and ConvaTec has now produced a soft silicone foam dressing specifically for low to non exuding chronic and acute wounds (Figure 1).1 Not all soft silicone dressings are the same and it is important to select the most appropriate soft silicone dressing for the patient and the wound.2
Foam Lite™ ConvaTec is a light, soft to touch silicone foam dressing dedicated to the everyday management of wounds that healthcare professionals frequently encounter. The dressing consists of a polyurethane (PU) foam layer with an outer breathable film, and has a perforated, gentle, skin-friendly silicone adhesive.
The requirements of Foam Lite™ ConvaTec are:
- Ability to manage low levels of exudate
- Help to maintain a moist wound healing environment
- Protect the wound and peri-wound skin
- Gentle on the peri-wound skin upon positioning, repositioning and removal
To provide comparative in-vitro data for a range of silicone foam dressings with respect to: adhesion, conformability, thickness and fluid management.
The following dressings were assessed:
- Foam Lite™ ConvaTec
- Allevyn® Gentle Border Lite
- Biatain® Silicone Lite
- Mepilex® Border Lite
In-vitro Methods & Results:
A combination of standardised in-vitro tests for absorbent dressings and for adhesive film dressings allowed a good overview of the physical performance characteristics: adhesive peel strength, conformability, thickness and fluid handling capacity.
Fluid Handling Capacity:
The technique used for measuring in-vitro fluid uptake of dressings is as described in BS EN 13726-1:2002 (Test Methods for Primary Wound Dressings. Part 1: Aspects of Absorbency, Section 3.3). The total Fluid Handling Capacity (FHC) is defined as the sum of the test solution (Sodium Calcium Chloride BP (Test solution A)) absorbed by the dressing and the weight of the fluid lost by moisture vapour transmission (MVT) through the dressing.
This in-vitro thickness test measures the thickness of the dressing pad area and surrounding border area without the presence of a release liner, in millimetres. This test is based upon an industry standard method (ISO 9073-2:1995 (Textiles - Test methods for primary wound nonwovens – Part 2: Determination of thickness)). Figure 3 shows that the thickness of all dressings tested is similar, all dressings evaluated showed a similar slim profile.
Conformability is designed to assess the extensibility – force required to stretch the dressing by 20% at a rate of 300mm/min (BS EN 13726-4:2003 Non-active medical devices - Test methods for primary wound dressings - Part 4: Conformability). The lower the force, the more conformable the dressing is. Foam Lite™ ConvaTec has the lowest force (Figure 4) and is therefore deemed to be the most conformable of the dressings assessed.3
Adhesive Peel Strength:
The adhesive peel strength was measured by placing a sample strip onto a polycarbonate plate and removing it (BP 1993,Volume II, Appendix XX, H, Adhesiveness, modified). Foam Lite™ ConvaTec demonstrated the highest peel force (Figure 5).3
In-vitro studies demonstrated that Foam Lite™ ConvaTec dressing has the following properties4:
- For low exuding wounds the hydrophilic foam layer of Foam Lite™ ConvaTec dressing absorbs Solution A and has the ability to manage fluid through a combination of absorbency and Moisture Vapour Transmission
- The thin flexible soft foam layer of Foam Lite™ ConvaTec is may help the dressing to conform
1. Cook, L. (2012) The Practical Use of Foam Dressings. Wound Essentials, 2. pp. 84-89
2. Meuleneire, F and Rücknagel, H. Soft silicone dressings made easy. Wounds International. 2013
3. ConvaTec Data on File. WHRI4723 MS133 In-vitro Performance Characteristics of Foam Lite™ ConvaTec and Competitor Dressings (16 June 2016)
4. ConvaTec Data on File. WHRI4680 MS132- In-vitro performance characteristics of Foam Lite-R1 (23 May 2016)