Pressure sores, also known as pressure ulcers, ischemic ulcers and bedsores, are a common hazard for people who spend hours daily in a wheelchair.
Not everyone is at risk, though, and for many, using a relatively inexpensive foam rubber or gel wheelchair cushion is fine, as long as it’s comfortable.
For others, specially designed cushions can help reduce the risk of pressure sores, or in some cases mitigate damage that’s already occurred.
Pressure sores are an injury to the skin and the tissue beneath it. In people with lighter-colored skin, they begin as an area of redness; for those with darker skin, they are more purplish. If left untreated, pressure sores can result in infections that penetrate to muscle and even bone.
An area of discoloration that lasts more than 30 minutes is reason to begin treating for pressure sores. Don’t wait for a wound to form, as open wounds often are slow to close, and healing seldom is perfect. Christopher Reeve, the actor who portrayed Superman and later was paralyzed in an equestrian accident, died from complications caused by a pressure sore.
For wheelchair users, pressure sores most commonly occur on the hips or coccyx (tailbone), which bear the body’s weight when sitting.
Wendy King, physical therapist at the MDA/ALS clinic at Ohio State University, said pressure sores can be caused by a variety of influences, sometimes in combination. The single pivotal cause is too much pressure on the skin for too long. Pressure keeps blood from reaching the skin, so the skin dies. The situation can be aggravated by poor nutrition, incontinence (moisture irritates wounds), stress and poor hygiene.
People with muscular dystrophy who use wheelchairs actually have fewer problems with pressure sores than those with spinal injuries who have lost physical sensation, said King. “They’re able to feel the discomfort, and shift themselves or ask a caregiver to shift them.”
Pressure sores seem to be most prevalent in older boys who have both Duchenne muscular dystrophy and a cognitive disorder, said King. “Even if they feel pain, they’re not apt to be vocal about it,” she said.
The National Pressure Ulcer Advisory Panel (NPUAP) instructs wheelchair users to shift their bodies every 15 minutes to avoid sores. For people who can’t shift on their own, NPUAP recommends that caregivers help them reposition at least once every hour.
NPUAP doesn’t make specific recommendations for cushion brand names, but warns that neither doughnut-shaped nor sheepskin cushions should be used for pressure redistribution. Kate Eichinger, a physical therapist at the University of Rochester, N.Y., encourages wheelchair users to lean forward and side to side periodically to shift pressure points. “If the person’s wheelchair has a tilt-and-recline mechanism, that will shift pressure, too,” she said.
Not a universal fit
Eichinger notes that a cushion that works for one person may be inappropriate for another.
Wheelchair cushion makers offer a variety of products to deal with pressure sores, each at least a bit, and sometimes a lot, different than others. Prices range from about $400 to nearly $4,000.
Here’s a brief overview of several different types of cushion technology.
Michael Ward, 62, of Forest Grove, Ore., has ALS, and as a full-time wheelchair user, knows the pain and discomfort pressure sores can cause. Ward battled pressure sores for years and finally got to the point where he had to lie back in his recliner chair for hours a day to relieve pressure on damaged areas on his hips.
He tried different types of cushions and eventually found relief in a cushion that varies its internal pressure every few minutes with a motorized pump — known as an alternating pressure cushion.
Alternating pressure cushions feature cells that inflate and deflate automatically to desired pressures on an adjustable timed cycle.
Ward uses a cushion designed by Rex Taylor, owner of Ease Cushion, who also has firsthand experience with pressure sores. As proof, a photo of his bare backside is posted on his company’s Web site, pressure sore scars and all.
Taylor, an engineer who invented his own “active alternating pressure” wheelchair cushion, says an engineering approach proved superior to a medical one. “I am constantly amazed at the medical community,” he says. “Time after time I’ve seen people have pressure sore after pressure sore, have it repaired by surgeons, and then the now newly healed person’s butt is placed back in the chair on the very same inadequate cushion that gave him pressure sores in the first place.”
Taylor maintains that while pressure is an issue, the primary cause of sores is lack of movement that causes poor blood circulation. His CCPM (computer controlled pressure management) technology addresses that problem by changing the pressure points under the wheelchair user every four minutes. Rechargeable batteries power automatic air pumps.
Over the past year, Goodrich Corporation (through its subsidiary Goodrich Aircraft Interior Products and its Interior Specialty Seating Systems section) has been testing Ease Cushions in fighter aircraft, where pilots typically sit in cramped spaces for prolonged periods.
Isolating individual air cells
Star Cushion Products’ alternating pressure cushions use “Star Lock” technology, which it says deals effectively with problems such as instability, “sloppy transfers” and user posture.
Star cushions, which are inflated by hand with a squeeze bulb, provide a "low-pressure, low-shear, low-friction seating environment,” said company president Ken Fraser. (Shear refers to the dragging effect on skin when a person transfers to and from a wheelchair.) Lock technology allows users to isolate up to 62 individual air cells [in the cushion] and customize “no contact” areas, without the added expense of a custom cushion.
Another version of an alternating pressure cushion is made by Aquila, whose Airpulse PK wheelchair cushion has been approved by the federal government for sale to the Veterans Administration.
Like the Ease Cushion, Aquila’s inflator can operate off its own rechargeable batteries or, as with Star, can be hand-pumped. In addition, via its Hybrid Control Box, it’s able to draw power from power wheelchair batteries.
Cells that twist, turn
Supracor’s wheelchair cushions don’t utilize alternating pressure but contain a thermoplastic urethane that the company calls Stimulite Honeycomb.
Stimulite is a “cellular matrix” of alternating thick- and thin-walled cells that flex when compressed, to relieve pressure. Each cell of the honeycomb is perforated to allow air to flow vertically and horizontally, to keep body temperatures from rising and prevent humid conditions that could aggravate sores.
Air flow also is a feature in several models of Cool-Comfort cushions from AireRx Healthcare, using electric fans (operating on rechargeable batteries) built into the cushion itself. The fans circulate air around the user’s bottom, preventing heat build-up problems.
“Compressible materials typically used in pressure-relieving cushions also act as thermal insulators and retain body heat. At the hotter skin temperature, sweat inevitably accumulates and contributes even further to the risk of skin breakdown,” said AireRx director of design and engineering Keith Ford.
The Roho Group’s Dry Floatation technology in its High Profile cushions features multiple rows of cylindrical bladders (cells) that move independently. Air pressure can be maintained at different levels by using a hand-held pump.
Roho says its cushion design allows each cell to twist and turn to adapt to the anatomical contours of wheelchair users, in effect “immersing” them in the cushion. That means “the cushion pressures pushing back are kept equal at all points and greater contact area is achieved for dispersion of pressure,” the company explains.
Varilite’s non-adjustable Reflex cushion features a built-in air-release device that allows a fixed amount of immersion and prevents bottoming out. Air supports the user’s weight while foam keeps the air where it’s needed and preserves the cushion shape.
Amara is a line of wheelchair cushions developed by Blue Chip Medical. Jim Acker, Blue Chip vice president of sales and marketing, says the Amara series’ strong point is that different types of inserts — variously made of elastic foam, viscous gel, solid gel or “Dynamic Air Cell” material — can be placed in a standard cushion base.
“The choice of inserts allows rehabilitation specialists to streamline their choice of cushions into one product line,” Acker said. “The low profile and light weight help distribute pressure and prevent skin breakdown.”
Sit on it
Unquestionably, many different types of products are available in the wheelchair cushion market today. Whether one design is better than others to prevent or promote healing of pressure sores is a question that must be answered by wheelchair users in conjunction with their doctor and rehab specialist. Certainly it would be wise to “field test” various models before buying.
Some dealers or manufacturers offer cushion try-outs for up to several weeks but charge a fee for doing so. Others charge a fee that can be deducted from the purchase price if the wheelchair user decides to buy. Check with individual dealers to determine their policy in this regard.
Eichinger, at the University of Rochester, said devices called pressure mapping systems are available at some wheelchair vendors’ stores as well as physical therapists’ offices. The systems pinpoint each individual’s pressure contact points while seated, and may prove useful in selecting a cushion that will ease pressure at those points.
However, King warned that in people with muscular dystrophy and other neuromuscular diseases, pressure contact points can shift as the disease progresses, making it necessary to be re-evaluated and perhaps change cushions.