Of pressure sores and wheelchair cushions
by Peter Tan. Posted on July 13, 2013, Saturday
CUSHIONS are simply padding over hard surfaces for the buttocks.
Many of us do not give them much thought as long as they are comfortable. For people with limited mobility, it is a different story as the cushion or the lack of it can be a matter of life and death.
People who are unable to shift their weight are at risk of developing pressure sores. This is true of wheelchair users with little or no sensation in their buttocks. Prolonged pressure against the skin and underlying tissues restricts blood circulation and causes the tissues to eventually break down and die.
In a sitting posture, the most susceptible areas are bony protuberances that are not well padded with muscle or fat. Pressure sores of the ischial tuberosity, also known as the sitting bones, and the sacrum, also known as the tailbone, are prevalent, even among active wheelchair users.
The severity of a pressure sore is categorised into four stages. Stage I indicates redness over a bony protuberance with the skin still intact. At Stage II, the skin has broken exposing a shallow wound that is raw. The wound at this stage can easily heal with conservative treatments.
When a pressure sore progresses to Stage III, there is a significant loss of underlying tissue and a moderately deep open wound. At Stage IV, the sore has advanced to the extent of severe tissue loss where the bone, tendon or muscle is exposed and damaged.
At these two stages, it will take months and tens of thousands of ringgit to treat. Surgical procedures are required to remove dead and infected tissues. Healthy tissues and skin are then taken from other parts of the body and used to cover the wound to expedite the healing process. Complete bed rest at this stage is essential to relieve direct pressure to the healing wound.
At its worst, an untreated pressure sore will lead to septicaemia where bacteria get into the bloodstream. This is a life-threatening condition that can result in organ failure and death. I have lost several friends due to this because they did not bother to seek proper medical attention for their sores until it was too late.
The occurrences of pressure sores are not only limited to the buttocks or while sitting in a wheelchair. Sores can also develop from lying in the bed for lengthy periods of time without shifting position. Bony areas of the body such as the shoulder blades, elbows, ankles and heels are spots that are commonly affected.
Having said that and realising the risks, I have to admit that I have only started using a proper wheelchair cushion for the past six years.
I am not proud to say that I have suffered several Stage II pressure sores over the years prior to that. Fortunately, they healed quickly with lots of bed rest and the application of iodine on the wounds.
Getting a wheelchair cushion is a matter of affordability versus suitability versus durability. A good cushion costs between RM1,000 and RM2,000. Not every wheelchair user can afford this amount, especially when he or she is unemployed and has to depend on the family in every aspect.
Some cushions are easier to maintain and more durable than others. All these have to be taken into consideration when making a selection. A cushion should require the least maintenance in order not to inconvenience the user. Likewise, a cushion that can last several years is preferable over one that wears out easily and needs to be replaced often.
Pressure mapping is the first step towards getting a proper cushion. The procedure consists of sitting on a sensor pad placed on top of a cushion to evaluate its effectiveness in reducing pressure to the buttocks. Physiotherapy clinics in major hospitals usually provide such evaluation for their patients.
The results are displayed on a monitor showing areas of high and low pressure while seated. Different people will get different results from the same cushion.
The best cushion is one that exerts the lowest pressure against the buttocks. I was moved to use a good cushion after a pressure mapping evaluation revealed that I was at high risk of getting pressure sores sitting in my wheelchair without one.
Basically, there are four types of wheelchair cushions that are popular in Malaysia. The first is polyurethane foam which is used extensively in sofas, mattresses and car seats. It is easily available and relatively inexpensive. However, it provides poor ventilation, retains moisture, is difficult to clean when soiled and tends to bottom out very quickly. When it bottoms out, the buttocks are effectively not protected. This can lead to pressure sores.
The gel cushion is widely used due to its heat absorption property. Its thick viscosity allows it to distribute weight over a large area to reduce pressure on a specific spot. The downsides to a gel cushion is that it is heavy, has poor shock absorption and can leak. The non-permeable layer that contains the gel also prevents moisture from dissipating.
An air-filled cushion consists of a matrix of interconnected cells that can absorb shock well apart from distributing weight over a large area. When properly inflated, it is effective in relieving pressure. The disadvantages are that it is high maintenance as it needs to be pumped up every now and then and the cells can become punctured, causing it to bottom out without the user realising it.
The honeycomb cushion is made from polymers of plastic and latex. The honeycomb cells are effective in drawing away heat and moisture from the buttocks. The cushion is light, durable, has excellent shock absorption properties and can be easily cleaned. This cushion is essentially low maintenance with low possibility of bottoming out.
A good cushion is as important as a good fitting wheelchair. While it may be expensive, one has to weigh the benefits against risks of not using one. A pressure sore is easier to prevent than treat. A pressure sore will also cause the loss of independence and productivity when one has to stay in bed for months while waiting for it to heal.
Wheelchair users can spend as many as 16 hours or more sitting up. Therefore, a suitable cushion together with pressure relief methods such as changing position often and performing wheelchair push ups are crucial in reducing and preventing pressure sores from developing.
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