Management of Shear, Pressure and Microclimate by Foam Dressings
Jodie Lovett, Senior Development Technologist, Crawford Healthcare
Christian Stephenson, R&D Director, Crawford Healthcare
It is widely recognized that pressure ulcers are caused by a number of contributing factors; of which not only pressure, but also shear and microclimate are significant. The aim of this study was to assess four foam dressings for the redistribution of pressure and shear forces, and the control of microclimate at the skin surface.
Pressure and shear forces were measured when a weight was applied to a pressure sensitive mat. A dressing was then applied between the mat and the weight, and the effect of this on the pressure and shear forces measured. Six replicates were conducted for each dressing. To measure microclimate, dressings were applied to a high humidity-containing chamber (~90%RH), and the change in humidity within the chamber measured over eight hours at a constant temperature.
When the weight was applied directly to the pressure mat, the average pressure recorded was 55mmHg, and the average pressure gradient (shear) was 21mmHg/cm. When Dressing A was placed between the weight and the pressure mat, the average pressure reduced by 52%, and pressure gradient (shear) by 46%. The other dressings tested reduced the pressure by 32% (B), 33% (C) and 22% (D), and the average pressure gradient (shear) by 35% (B), 28% (C) and 31% (D).
After eight hours on the microclimate test chamber, Dressing A had reduced the humidity to 58%RH, Dressing B to 75%RH and Dressings C and D to 83%RH.
Whilst this study has shown that all of the dressings reduced the pressure and shear forces generated by the weight, it has indicated that not all dressings are able to do this to the same extent. Dressing A maintained a much lower humidity in the microclimate test chamber; indicating that this dressing generated a more favorable microclimate; removing excessive moisture, whilst not completely drying out the environment.