I heard a clinician speaking about the importance of matching clients with the right wheelchair
cushions, so that their skin can breathe, to which I wanted to ask, “Exactly what type of amphibians
are you seating – frogs?”|
Of course, we, humans, don't breathe through our skin – the clinician
merely made a common mistake, choosing the wrong words for the real issue, heat build-up and perspiration
from sitting. See, when we place a surface like a seat cushion against our body, it traps our body heat,
we perspire in that region, then that moisture can cause skin breakdown – as in, pressure sores – if
not promptly removed. Therefore, as those sitting on wheelchair cushions, our goal is to minimize heat
from the seated region of our bodies, and promptly wick away any perspiration that occurs. Fortunately,
both of these goals are facilitated with the right pressure-management cushion and cover materials.
Heat: From the Inside, Out
If you think about a seat cushion as an insulating layer against the
seated region of your body, it becomes obvious that the cushion's material, itself, plays a role in regulating
Gel proves as among the “coolest” seating surfaces because it doesn't retain heat
as well as other materials. In fact, if you've ever touched any sort of “gel” material, then you've experienced
how it's usually cool to the touch. In this way, while a gel pack still traps body heat by nature of
its sealed pack being against the body, its intrinsic heat-dissipating properties keeps the gel cooler,
thereby keeping the seated area cooler, which helps minimize perspiration.
foam seating surfaces are insulating to varying degrees, based on the type of foam, so they do trap body
heat to an extent. However, some newer cushion technologies use “engineered foams” that are extremely
porous, like a honeycomb or filter, allowing air to circulate within them, dramatically dissipating body
heat, to the tune of 3-degrees cooler than other cushions.
Despite their name, air cushions
prove among the least effective at dissipating body heat, where very little air circulation or “cooling”
occurs. While some manufacturers claim that air can circulate in-between the cells of an air cushion,
the fact is, when you're seated on the cushion, it spreads the cells into each other, creating an almost
constant barrier against your body. Furthermore, most air cushions are made out of neoprene – a material
that's a literal insulator – trapping body heat. For these reasons, air cushions are often the least
effective at dissipating body heat.
Now, this isn't to say that of the three materials – gel,
foam, and air – any one is least effective at overall pressure management than the others. Truly, they
all prove exceptionally meaningful at pressure relief for specific individuals. However, if heat build-up
is an especial concern for you, then the properties of cushion materials in this aspect most certainly
come into play.
When What's on the Surface Matters
Make no mistake, a cushion's cover plays
a foremost role in moisture control – and can even prove more consequential than a cushion's material,
itself, toward regulating heat build-up.
Sheepskin was once thought by many as among the best
materials to decrease heat and moisture build-up. And, while that was true compared to circa 1970s vinyl
(which had no moisture-wicking properties), modern seating covers prove sheepskin as among the worst
materials to sit on. Sheepskin is an insulator – wool – that is among nature's finest material at trapping
body heat, so while sheepskin wicks away moisture, it dramatically increases perspiration, the antithesis
of a healthy-inducing cushion cover. Therefore, in modern wheelchair seating, sheepskin covers are avoided.
Contrary to the sheepskin and vinyl cushion covers of the past, today's covers are engineered for
1.Reduce heat build-up by not insulating the body
2.Wick moisture away from
3.Stretch to optimize conforming to pressure relief surface
4.Provide a low-shear
surface to reduce skin tension
The result is that most pressure-management cushions today use
variations of moisture-wicking Lycra materials that are strikingly along the lines of an athletic clothing
brand that you might know, Under Armour. In fact, Under Armour describes their material as “wicking moisture
away from your skin, and helping regulate your body's temperature” – and that's exactly what modern moisture-wicking
cushion covers accomplish.
Because today's pressure-management cushions covers perform so well
at reducing heat build-up and wicking away moisture, it's inadvisable to use any cover material beyond
that which was engineered with the cushion.
No, modern pressure-management cushions and covers
may not look as plush as sheepskin, but they're that way by design – that is, to keep your seated regions
Published 4/2010, Copyright 2010, WheelchairJunkie.com