Why is the comfort of wheelchair cushions so variable from one brand of cushion or type of cushion to another? Why does a wheelchair cushion initially feel comfortable, but in a short time becomes uncomfortable? Are there any wheelchair cushions that will provide extended comfort? The best answer to those questions is to understand how each wheelchair cushion works when a client’s shape and weight is placed on top. Let’s investigate the various types of wheelchair cushion materials to determine the comfort level of each. This article will compare foam, air, liquid and buckling column cushion technologies. See which is best for you.
Foam began to be used in cushioning in the early 20th century and has now become the most popular material used in wheelchair cushioning. Foam comes in many densities which can make a cushion more or less firm.
Memory foam or viscoelastic was developed under contract by NASA for use in manned space vehicles. There is no indication that memory foam was ever used for the purpose for which it was developed. In the 1980’s NASA released the technology for memory foam to the commercial marketplace. The commercial marketplace has heralded memory foam as the ultimate cushioning material.
Some of the reasons for the popularity of foam are that foam is light weight, it can be shaped to fit the design requirements of a wheelchair cushion and over-all it is rather in-expensive.
When one places their weight and shape on a foam Wheelchair cushion the cushion compresses straight downward until it cannot compress any further. For someone of heavier weight they may “hit bottom” whereby the foam has reached its maximum compressed limit and cannot compress any further. The foam area beneath the weight is perfectly shaped around the clients buttocks and continues to press upward in equal pressure over the client’s posterior. The further one sinks into a foam wheelchair cushion, the greater the upward pressure against the client’s posterior. (This can be easily demonstrated by taking one’s finger and pressing it into a foam cushion. The further into the cushion that the finger is forced, the greater the upward pressure from the cushion against the finger.)
Hence someone can feel comfortable initially on a foam wheelchair cushion but after a short time the upward pressure against the pressure points within the posterior (ischial tuberosity’s, coccyx and/or trochanters) makes them uncomfortable and they need to re-position themselves. While that upward pressure is not technically considered “hitting bottom”, there is little difference in the feeling one gets when he/she does actually hit bottom.
Manufacturers of foam wheelchair cushions typically offer them in 2” to 4” heights and rate them with a maximum weight limit of 200lbs. to 250 lbs.
AIR AND LIQUID CUSHIONS
The scientific community considers air and liquids as fluids because they have the same properties and perform in the same manner. Because of this scientific fact this article will refer to both air and liquid in wheelchair cushions as “fluid” cushions.
Unlike foam that compressed when a client sits on a cushion, fluid is displaced. Just like when one takes a balloon and squeezes it, the air moves away from the squeezed area and expands the balloon in the area where there is no pressure. Also when one squeezes ketchup from a plastic bottle, the ketchup moves out of the opening. As such, the question can be asked, “Does fluid really cushion? Or does it just displace?
When a client sits his weight on a fluid wheelchair cushion, the fluid is displaced to the maximum boundaries of the material holding that fluid. If the fluid is tight within those boundaries then the wheelchair cushion will feel very firm. If the fluid is loose, the wheelchair cushion will feel softer. The client’s weight on the fluid wheelchair cushion produces the same results as on the foam wheelchair cushion – the weight goes straight down, the fluid wheelchair cushion shapes itself to the client’s posterior and continues to give upward pressure. The client’s pressure points, ischial tuberosity’s, coccyx and/or trochanters have the same pressure against them as the
fleshy part of the posterior. Pressing a finger into a fluid cushion will give the same results as was demonstrated with the foam above – the further one pushes his/her finger into the cushion, the more the cushion pushes back.
Therefore just like on the foam cushion, after a short time the client will become uncomfortable and will need to re-position him/herself to relieve the pressure from those pressure points.
Manufacturers of air and/or liquid cushions typically offer them in 1” to 4” heights and rate them with a maximum weight limit of 250lbs to 350lbs.
BUCKLING COLUMN CUSHIONS
The concept of buckling columns was introduced in the mid 1990’s for use in critical care wards of hospitals around the world. The success of the buckling column technology providing extended comfort, relief of pressure points and protection of skin integrity issues prompted the development of wheelchair cushions.
When a client sits his/her weight on a buckling column wheelchair cushion, the weight is evenly distributed over the top of the cushion while giving further relief to the client’s pressure points – ischial tuberosity’s, coccyx and/or trochanters. Therefore, instead of the client’s weight going straight downward to the maximum compressed state of the material as with foam and fluid cushions, cushions using the buckling column design evenly distribute the weight across the top of the cushion. As such, anyone of any weight or shape will not “hit bottom”.
Each of the column walls is designed to hold up very little weight. When that threshold is exceeded, the column buckles under and passes the weight bearing to the surrounding columns. Using the finger pressure as described for the foam and fluid cushions, one will see that when the column buckles, it does not push back.
Therefore people of all sizes and shapes experience extended comfort and further relief of pressure on their pressure points when sitting on an EquaGel wheelchair cushion. Their full weight is evenly distributed over the top of the cushion while their pressure points (ischial tuberosity’s, coccyx and/or trochanters) are given additional relief from upward pressure. No other cushion type provides the ultimate comfort level of EquaGel wheelchair cushions.
There is only one wheelchair cushion manufactured using the buckling column technology and that is EquaGel. The EquaGel wheelchair cushions range in height from 1-3/4” to 2-1/2”. The EquaGel wheelchair cushions provide extended comfort like no other cushion.
None of the EquaGel cushions has a weight limit. Anyone of any weight or shape will not hit bottom on an EquaGel cushion.
EquaGel wheelchair cushions are available in sizes from 16” wide to 30” wide and 16” depth to 20” depth. Most are Medicare coded for reimbursement. They are available from GelTechCo, LLC (www.geltechco.com).