Pressure Sores

Pressure sores (also called pressure ulcers, decubitus ulcers, or bedsores) are areas of damaged skin that result from prolonged pressure on the skin. Pressure applied for as little as 2 hours can damage the skin and cause a pressure sore.

Pressure occurs when the skin is pressed between a bone and a hard object, such as a bed, wheelchair, or cast. Pressure prevents blood from reaching the tissues.

Pressure sores are common among people who are confined to bed or a wheelchair, especially those who have reduced sensation or difficulty changing their position. Pressure sores develop in about one fourth of nursing home residents.

Pressure sores develop in stages. They usually start with redness on the surface of the skin and may penetrate through the layers of the skin and eventually reach muscle and bone. Pressure sores can become infected. The infection can spread to nearby skin, bones, and joints. It can also spread through the blood. Serious infections are more likely to develop in deep sores.

See the figure Where Do Pressure Sores Develop?

Most often, pressure sores develop on skin over a prominent bone (such as the hip, tailbone, elbows, or heels), especially if the layers of muscle and fat between the bone and the skin are thin.

Preventing pressure sores is preferable and usually easier than treating them. Many pressure sores and the infections that result from them can be treated effectively.

Causes

The skin needs a steady supply of blood to stay alive. Pressure can cut off the skin's blood supply or even make blood vessels rupture. If the blood supply is greatly reduced for more than an hour or two, the skin deprived of blood may die.

Aging itself does not cause pressure sores. But it causes changes in tissues that make pressure sores more likely to develop. As people age, the outer layers of the skin thin. Many older people have less fat and muscle, which help absorb pressure. The number of blood vessels decreases, and blood vessels rupture more easily. All wounds, including pressure sores, heal more slowly.

Certain conditions make pressure sores more likely to develop:

• Being unable to move normally (immobility) because of a disorder such as stroke. Such people tend to stay in one position, putting pressure on one area for too long.
• Having to stay in bed for a long time, for example, because of surgery.
• Being excessively sleepy. Such people are less likely to change position or ask someone to reposition them.
• Losing sensation because of disorder such as nerve damage (neuropathy). Such people do not feel discomfort or pain, which could prompt them to change positions.
• Becoming less responsive to what is happening in and around them, including their own discomfort or pain, because of a disorder such as dementia.

Anything that makes sores or injuries on the skin's surface heal more slowly can contribute to the development of pressure sores. Examples are undernutrition, diabetes, smoking, poor circulation (peripheral arterial disease), and the use of corticosteroids.

Moisture that remains in contact with the skin for a long time can irritate it, sometimes causing it to break down. Then, pressure sores are more likely to develop. People who cannot control bowel movements or urination (are incontinent) are prone to pressure sores, because feces or urine may remain in contact with the skin for a long time.

Pulling or rubbing on the skin excessively can contribute to the development of pressure sore. These actions (which can occur when a person is repositioned) can injure the skin by stretching it or creating friction against it.

Symptoms

Symptoms vary depending on the stage of the pressure sore.

• Stage 1: The surface of the skin becomes red.
• Stage 2: If pressure continues, a blister or shallow crater forms because the outer layer of skin dies. It dies because it does not get enough blood.
• Stage 3: Pressure sores penetrate through the deeper layers of skin.
• Stage 4: All of the skin is lost, exposing muscle or bone.

Pressure sores may be painful. But many people who have them may not notice the pain, because they have lost sensation or they no longer respond to what is happening to them.

If pressure sores become infected, they usually have an unpleasant odor. Pus may be visible in or around the sores. The area around the pressure sore may become red or feel warm, and pain may worsen if the infection spreads to the surrounding skin (causing cellulitis). If deep pain lasts several days or longer, the cause may be infection of the bone (osteomyelitis). If a joint swells and becomes painful (particularly when it is moved), the cause may be an infection in the joint (septic arthritis). If a person has fever or shaking chills or suddenly feels ill or weak, an infection may have spread throughout the body via the blood. This infection is called sepsis. Any change suggesting infection requires immediate medical attention.

Diagnosis

A doctor diagnoses pressure sores by their appearance. A nurse or doctor usually measures the size and depth of a sore to determine its stage and to plan treatment. If the pressure sore appears to be infected, a sample of the sore is sometimes taken and cultured so that bacteria can be identified. However, such tests are often unhelpful. Results of cultures taken from the sore's surface are always unhelpful.

Prevention

Usually, pressure sores can be prevented. If a person is likely to develop pressure sores, a concerted effort to prevent them should be made by all caregivers as well as the person (if able).

Changing positions frequently is important. Caregivers should encourage activity. Caregivers should turn or reposition people who cannot move themselves. Such people, whether asleep or awake, should be moved every 2 hours. Moving them less often does not prevent ulcers from forming. Drugs that cause drowsiness and thus make people move less are avoided or used sparingly.

If a person is confined to bed or a wheelchair, closely inspecting the skin each day is important. If the skin is red or discolored, a caregiver should reposition the person more frequently. The person should be kept from lying or sitting on the affected area until it returns to normal.

The skin must be kept clean and dry because moisture irritates the skin, increasing the chance of developing pressure sores. Dry skin is less likely to stick to fabrics (including sheets) and to tear. For people confined to bed, sheets should be changed frequently to make sure they are clean and dry. Applying noncaking body powder to skin in areas where two parts of the body press against each other (such as the buttocks and groin) can help keep the skin in these areas dry.

Pulling and creating friction on the skin should be avoided. One way is for caregivers to learn the safest way to reposition the person. Another is to use sheepskin to cover a bed or chair and thus reduce friction on the skin.

Areas where bones are prominent, such as the heels and elbows, can be cushioned with soft materials, such as cotton or fluffy wool. Special beds, mattresses, and seat cushions that contain water, gel, or air can reduce pressure on areas where pressure sores tend to develop. Foam mattresses and cushions do little to help prevent pressure sores. A doctor or nurse can recommend the most appropriate type of mattress or seat cushion for people who are confined to a bed or a wheelchair. However, these devices do not eliminate pressure. Even when the devices are used, people still need to be repositioned frequently.

Protein and calorie supplements may help prevent pressure sores in undernourished people. With adequate nutrition, the body's ability to heal itself improves. A person may also gain some fat, which can cushion the skin and sometimes help prevent pressure sores.

Treatment and Outlook

Pressure sores on the surface of the skin can heal on their own if the skin is kept dry and is protected from prolonged or intense pressure. Usually, deeper sores require additional treatment. Sores that heal on their own do so very slowly.

The main goals of treatment are to relieve pressure on the pressure sores, keep them clean and free of infection, and provide adequate nutrition. If the person is undernourished, protein, calorie, vitamin C, and zinc supplements may help pressure sores heal more quickly.

Dead tissue must be removed with a scalpel or chemical solution. Removal of dead tissue is usually painless, because pain is not felt in dead tissue. Some pain may be felt because healthy tissue is nearby. Health care practitioners may flood (irrigate) the sore, particularly its deep crevices, with a sterile solution to help clean away hidden debris.

Most pressure sores should be cleaned at least once a day with a sterile solution. The only exceptions are sores covered with a dressing that must remain in place for 3 to 5 days. Such dressings are designed to form tight barriers over a sore to keep it from drying out and to keep microorganisms that can cause infection from getting in. Except when cleaning or another treatment is needed, pressure sores should remain covered with special dressings that do not stick to the sores. For a severe pressure sore on a foot or the lower part of a leg, a paste is applied to the foot and leg. The paste hardens and is wrapped with a bandage, forming a soft, castlike boot (Unna boot). The boot provides extra protection.

Sometimes a bed that circulates air (air-fluidized bed) is used in hospitals or nursing homes. This special bed helps deep sores heal more quickly by reducing or redistributing pressure on the body.

Sometimes if a pressure sore is deep, healthy skin is removed from another part of the person's body and applied (transplanted or grafted) over the sore. Skin transplantation or grafting can help prevent infections and speed healing. However, it may be too risky for people who are frail or undernourished.

If all other treatments are ineffective, an area of skin next to the pressure sore is cut and folded over the sore. This procedure is called flap surgery.

Unless the conditions that contributed to the development of pressure sores are corrected, ulcers are likely to recur, even after skin grafting. Flap surgery reduces the likelihood of recurrence but does not eliminate it.

Infections are treated with antibiotics. Some infections, particularly those in the bones, can be difficult to cure and may require weeks of antibiotics. Protein, calorie, vitamin C, and zinc supplements can help the body fight infection.

If a serious infection develops, people often have to stay in a hospital for a long time. Many older people with pressure sores die within a year or two. However, death often results from the disorder that caused the person to become confined to bed or immobile rather than from the pressure sores.