Microclimate Comparison of Five-Layer Foam Dressings

Prophylactic use of five-layer foam dressings to reduce the risk of developing a pressure injury (PI) is a key component of a PI prevention protocol. These dressings mitigate contributing PI forces such as microclimate – skin surface temperature and humidity at the skin-dressing interface.

The purpose of this in-vitro study was to compare the microclimate between a simulated sacral area and three five-layer dressings using sensitive instrumentation. The materials were preconditioned at test conditions for a minimum of 12 hours prior to testing. The indenter was weighed achieve a total load of 285 N ± 10 N and set to 37°C. Towels were moistened and placed inside the indenter so as to cover all of the holes, “sweat pores”. Six sensors were placed on the indenter to measure temperature and relative humidity, three directly and three on the applied dressing: at each ischial tuberosity location and the centerline. A seventh sensor measured the ambient temperature and humidity. The indenter was attached to an H-frame. Foam cushions were covered with mattress cover fabric and placed on testing platform, centered below the indenter.

The indenter was allowed to reach 37°C and achieve a steady state, and the towels were re-moistened to account for evaporation. The dressing was placed on the indenter over the sensors and sweating pores.

The indenter was weight before and after dressing application. After 3 hours, the indenter was raised from the support surface to provide an air gap between the indenter and the support surface to simulate a pressure relief lift. Then the indenter was lowered back onto the support surface for another 15 minutes and raised again. Higher temperature and humidity increase the risk of breakdown. Although average temperature and humidity were higher on the patient side than the outside, the difference was not significant for each dressing, and there were no significant differences in temperature or humidity among the dressings, except dressing 1 had significantly lower humidity outside the dressing than dressing 2. There was also no significant difference in moisture retained among the dressings.

Overall, there was no significant difference in microclimate among the dressings.