The Lurking Dangers of Pressure Sores

by Phil Ivory on February 1, 1999 - 9:45am

Pressure sores and bed sores are terms that basically refer to the same problem, the formation of a wound due to prolonged pressure on a particular point on the body.

The term pressure sores is perhaps more useful than bed sores, since it includes injuries caused by being in bed as well as those that result from sitting in a wheelchair or using an orthopedic device that presses against the skin. Decubitus ulcer is a term doctors use to describe any such sore.

The problem is a common one in nursing homes and among people with disabilities. But just because it's common doesn't mean it isn't also quite serious.

Once formed, pressure sores can take months to heal, can be quite painful, and can complicate and add to existing health problems. In worst cases, they can actually become life-threatening.

However, there are steps that can be taken to stop them from getting worse once they've formed or, better yet, to prevent them from forming in the first place.

Natural defenses

In a person whose nerves and muscles are healthy, the nervous system conveys a signal of discomfort to the brain whenever a part of the body has remained in one place too long and is receiving excess pressure. In response, the person shifts sitting position or turns over in bed, relieving the pressure.

In those with spinal cord injuries and other conditions associated with a loss of mobility and a loss of sensation, the individual may not be able to move to relieve the pressure and may not even be aware that a part of the body is under duress.

In contrast, in certain neuromuscular diseases such as Duchenne muscular dystrophy (DMD) or amyotrophic lateral sclerosis (ALS), sensory function largely remains intact. It may be partly for this reason that in patients with neuromuscular diseases, pressure sores aren't reported as often as might be expected.

In Amyotrophic Lateral Sclerosis (1998, F.A. Davis Company), Hiroshi Mitsumoto, David A. Chad and Erik P. Pioro cite a study which suggests that the biochemical properties of a protein called collagen (which is present in the skin) are different in people with ALS, and this difference may help protect them from pressure sores. Nonetheless, pressure sores can and do occur in ALS, particularly in later stages of the disease.

Certainly, even if sensory perceptions are intact, the loss of mobility associated with progressive neuromuscular disease will always create a danger of pressure sores.

In addition, unwanted curvature of the spine, or scoliosis, is a complication that often accompanies neuromuscular conditions. It can contribute to pressure sores because it causes the individual to lean to one side, placing disproportionate weight on one buttock.

Causative factors

Pressure sores are most likely to form at a point where the bone is close to the skin. Refer to Diagrams 1, 2 and 3 to see the "trouble spots."

[illustration] [illustration]
[illustration]

Prolonged pressure from a bed or chair on one side and bone on the other makes it impossible for the affected area of skin to be properly nourished by tiny blood vessels called capillaries. The area of skin starts to die. The greater the pressure, the more likely damage will occur.

Friction is another potential cause. Movement that causes skin to rub roughly against bedding may damage the capillaries and diminish blood supply at a particular point. Dragging someone across a surface instead of lifting the person can cause this.

Excess moisture on the skin that results if the person suffers from incontinence of the bowels or bladder can also contribute to skin breakdown. Perspiration caused by wearing a brace or other orthopedic device can have a similar effect.

General poor health, undernourishment and obesity are other possible factors leading to pressure sores.

In A Clinician's View of Neuromuscular Diseases (1986, William & Wilkins), Michael H. Brooke writes that pressure sores may form on the heels of boys with DMD whose legs have been temporarily immobilized after tendon-release surgery.

Recent evidence suggests that any patient undergoing surgery for more than three hours faces a risk of developing pressure sores, caused by immobility during the operation and the use of anesthesia.

Damage to the skin may occur during surgery but not develop into full-blown pressure sores until some time after the procedure. As a result, sometimes the surgery's causative role may be missed.

From bad to worse

In light-colored skin, the first warning sign of an impending pressure sore may be a soft, reddened area with no broken skin. If redness remains 30 minutes after the pressure is relieved, enough damage may have already been done that formation of a sore is unavoidable.

When seeking this sign in people with darker pigmented skin, it may be necessary to look for increased darkness rather than redness, or to check for a rise in skin temperature instead of a change in color.

It's imperative after noting this initial symptom to call in a nurse, doctor or other health professional, if one isn't involved already.

If a pressure sore continues unabated, the area will become blistered and then ulcerous, with a shallow opening in the skin, possibly accompanied by fluids draining from the site.

After that, the wound can become deeper, with destruction not only of the outer skin layer but also of the fat and muscle beneath, with increasing likelihood of pain and drainage.

In severe cases, if untreated, the wound can extend all the way down to the bone. At this point, there'll most likely be an excess of pus and dead tissue appearing in the site, with accompanying pain.

Fever and increased warmth around the wound are possible signs of infection, as is the presence of a green or yellow discharge. Once the site is infected, the surrounding tissues and the bone are also in danger of infection. Sepsis — the general spread of bacteria throughout the body — is a further possibility, paving the way for potentially fatal complications.

Treatment

The initial step in treating a pressure sore is to make sure that no additional pressure is placed on the site until it has had a chance to fully heal. The placement of special foam pads and pillows can help a person lie in bed without putting pressure on a wound.

A wound isn't considered to be healed unless the skin is once again unbroken and normal color is restored, aside from permanent changes in skin color due to scarring. Once the spot is healed, pressure must be placed on it for short trial intervals only, with careful checks made for any ill effects.

For an open wound, a doctor or nurse may need to show the affected individual or caregiver how to tend the injury. This care may involve cleaning or irrigating the wound, removing dead tissue and applying a dressing.

Saline solution may be adequate for cleaning some wounds. It can be bought or made at home. Deeper wounds may require more stringent cleaning and more elaborate care, with careful monitoring for any signs of infection.

Antibiotics may be in order if infection is detected. In extreme cases, surgery or other procedures may be necessary to remove dead tissue to enable the wound to heal.

A new kind of treatment not yet widely used is called vacuum-assisted closure therapy. Through application of an air-tight foam dressing and a vacuum pump, negative pressure is created around a wound to stimulate blood flow and encourage healing.

Prevention

Anyone who uses a wheelchair or must remain in bed for extended periods must be sure to change position regularly. Pressure sores can form in only a few hours.

Carol Stumpf, a physical therapist and manager of rehabilitation at University Medical Center in Tucson, Ariz., says a bed-bound patient should move or be moved at least once every two hours, if not more often.

A bed-positioning program might have a person lie on the left side, then on the back, then on the right side, all at two-hour intervals.

Using a specially designed bed, bed cover or mattress can help. These include air-filled, alternating-pressure mattresses; sponge-rubber mattresses with "egg crate" shaped modeling; and silicone gel or water mattresses. They adjust to the body's shape and help to spread pressure over a wider area. They don't, however, eliminate the need to change position every two hours.

One common sense strategy to prevent a person in bed from placing too much stress on one side of the body is to make sure that a TV is placed directly in front of the person, not on one side or the other.

For wheelchair users, pressure-relieving cushions filled with air or gel can increase comfort and guard against sores. But whether they're used or not, the individual will need to shift position as often as every 10 to 15 minutes. If he can't move himself, he should be moved at least once an hour.

Wheelchair users with sufficient upper body strength may be able to use a self-lifting exercise known as "wheelchair pushups," with doctor's approval.

People with neuromuscular diseases may benefit from using standing wheelchairs to occasionally relieve the pelvic area of the pressure caused by sitting.

For users of braces and other orthopedic devices, special protective pads or a layer of cotton clothing worn underneath the appliance may help discourage sore formation.

Checking the skin

Good hygiene is crucially important. For unbroken skin, cleaning gently with mild soap and water is appropriate, followed by gentle drying (patting, not rubbing). Skin shouldn't be allowed to be too moist or too dry. Overrigorous cleaning can chafe or cause excess dryness.

Ask your doctor if he recommends the use of any particular oils or lotions to help maintain skin quality. Shop wisely. No one agent is acknowledged to be universally superior in prevention or treatment of pressure sores.

Those in danger of developing pressure sores will need to create a daily skin-checking regimen. A parent of a child who uses a wheelchair should check the trouble spots in the morning when the child gets up and also whenever the child is taken out of the wheelchair or when an orthopedic appliance is removed. Adequate light should be available.

If the child wishes to be independent, he'll need to learn how to do this routine by himself, using mirrors if necessary.

Other factors

Bedding should be changed frequently and kept clean, dry and smoothed out. Bedding that is wrinkled or bunched can cause friction against skin and contribute to wound formation. Lying on a sheepskin or synthetic sheepskin seems to help protect against friction.

Good nutrition, too, is important in that it will help maintain healthy skin and make it more resistant to breaking down. Vitamins and mineral supplements might help.

Since circulation is a factor, it's possible that gentle massages and whirlpool treatments may be of value as preventative measures against pressure sores, although special gentleness must be used near the trouble spots.


More information on pressure sores is available online at the U.S. National Library of Medicine website. Click on "Health Information," then either "P" (for "pressure sores") or "MedlinePlus—Health Information" to conduct a search for "pressure sores."

You can also contact the National Pressure Ulcer Advisory Panel (NPUAP) by writing to NPUAP, 1025 Thomas Jefferson Street, NW, Suite 500 East, Washington, DC 20007 or by calling (202) 521-6789.

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