The ideal skin temperature is 32˚C, however, when sitting against a normal backrest the skin temperature rises 2.2˚C on average within 30 minutes. Tests show that the backrests’ temperature itself can easily increase from 23˚C to 34˚C in 100 minutes, creating lots of unwanted heat and moisture. This moisture can lead to skin maceration.
WheelAir reduces the temperature of the back 2.5˚C in 3 minutes and 8˚C in 30 minutes and lowers relative humidity.
Microclimate & moisture lesions
Moisture lesions or moisture-associated skin damage (MASD) is defined as inflammation and erosion of the skin caused by prolonged exposure to moisture. Unlike a pressure sore, MASD occurs on non-bony parts of the body too. Moisture lesions cause superficial loss of epidermis (the top layer of the skin) and/or dermis (the second layer of skin), which may be preceded by areas of erythema on intact skin.
The effect of moisture on the skin can be damaging when talking about trapped moisture, often a result of poor air circulation. Excessive moisture will affect the dermis by weakening the collagen and softening the stratum corneum in the epidermis which can lead to maceration. Macerated skin can be recognised as pink or white surrounding skin with non-uniformly distributed redness at the centre.
How and when does excessive moisture occur?
An increase in the metabolic rate increases the body tissues’ susceptibility to the ischaemic effects of shear and pressure. Sweat is produced in an attempt to regulate the body’s temperature. Equally, where the body and support surface come into contact, a rise in temperature may occur due to increased pressure, causing occlusion of the circulation, inflammation and an accumulation of warmth between the skin and the surface. As heat builds up, moisture will accumulate causing the skin to feel damp.
Whereas before repositioning the person or advising the person to reposition themselves was the only method to aid evaporation of the moisture from the areas and aid cooling of the affected areas preventing the build-up of moisture, the WheelAir technology will now do this automatically, without any necessary repositioning.
Microclimate & pressure ulcers
Pressure is just one key factor in pressure ulcer development. The microclimate is controlled at the seat surface and should be discussed when choosing the appropriate surface. It is important that the backrest is moisture and air permeable and that it will not lock moisture in that can soften and macerate the skin, making it more vulnerable to pressure and friction.
Areas prone to skin ulcers which WheelAir predominantly covers are the spine, sacrum and coccyx. When choosing a hard-shell back, attention should also be paid to the shoulder blades. Clinical evidence shows that elevated skin temperature leads to a higher incidence for tissue damage. Similarly, due to the moisture, the macerated skin in contact with a solid surface equals a higher coefficient of friction. Friction leads to skin shear, which leads to tissue ischemia and localised tissue necrosis.