Pressure Ulcers

Skin ulcerations caused by pressure and/or shearing stress are known under a variety of names, including decubitus ulcers, pressure ulcers, pressure sores, and bedsores. They are caused by impaired blood flow (perfusion) through the affected area, which reduces tissue oxygenation. This process is termed ischemia and results in partial or total tissue death. It occurs when there is concentrated external pressure on part of the body for a period of time. This commonly occurs in an area with a bony prominence, such as the knees, hips, or elbows, but it can also occur in a number of other areas if the underlying tissue of fat and muscle is thinned. The effect is enhanced if the skin vessels have been previously damaged by intermittent pressure.

Shearing occurs when there is a sliding movement on the skin surface, producing partial or complete disruption of the underlying tissues. Minor shearing forces, short of actual disruption, occur quite frequently and produce ischemia due to impairment of the blood flow. Any factor (e.g., bedsheets, moist skin) that increases frictional resistance of the skin surface will increase the tendency to shear.

Maceration results when the skin surface is moist and occluded for a prolonged time. The outer part of the skin becomes whitish and soggy, and bacteria and other organisms can then proliferate. Such organisms invade when a slight abrasion occurs, and the resulting infection can lead to skin breakdown. Even minute foreign materials on the skin surface, such as dried bread crumbs or other debris, can cause local ischemia and thus promote breakdown.

Care must be taken to distinguish harmless colonization of bacteria from the pathological state of infection. The presence of inflammation (redness, heat, pain, and swelling) characterizes infection.

General factors that can increase the risk of pressure ulcers include poor nutrition, debilitating illness, clouding of consciousness causing immobility, and impending death. Conditions that predispose a person to bedsores include urinary or fecal incontinence, insensitive skin, peripheral vascular disease through arteriosclerosis or diabetes, and being underweight or overweight. The incidence of this condition in hospitals provides clues as to standards of care. It has been recorded variously as being between 2.7 percent and 29.5 percent, with a prevalence of 3 to 5 percent. When a pressure sore occurs in the elderly or immobile in a nursing home, there is a fourfold increase in the risk of death.

A number of classifications of ulceration have been used, but that of the National Pressure Ulcer Advisory Panel (NPUAP) is now generally favored (see Table 1).

The economics of bedsores is also important. It is difficult to estimate the cost of ulcer management, as settings vary from acute-care institutions to chronic-care nursing homes. For acute care, one estimate put the cost at between $5,000 and $40,000 per patient per year. The cost is significantly less in chronic care institutions.

To prevent bedsores, an optimal nutritional state must be achieved. In particular, a positive protein balance and adequate Vitamin C, iron, and zinc levels are required. Debilitated elderly persons, the mentally disabled, and those with dietary deficiency due to social circumstance are all at risk. For those at risk, the daily nursing routine must include inspection at least once daily. The bedridden should be turned at least every two hours, with good nursing techniques used to avoid friction and shear. Skin moisture and soiling must be minimized.

There are a number of ways in which pressure can be redistributed from bony prominences and other predisposed sites. Pillows or foam wedges are used to separate limbs. Doughnuts are not used, as they can increase pressure. Wheelchair cushions should be made of foam, viscoelastic foam, gel, or fluid flotation. Similarly, mattresses of the air pressure, water, air-fluidized, or air-support types are recommended. Team consultation, combining doctors, attending nurses, physiotherapists, occupational therapists, and equipment suppliers can be most helpful in planning the various stages of management (see Table 2).

The affected areas should be dressed using surgical gauze in combination with certain other materials. Films are thin, transparent, semipermeable, and nonabsorbent. They can be left in place for one or two days. Hydrocolloids are adherent, impermeable to gas, and are absorbent. They conform to the area on which they are used and can be left for a few days on deeper wounds. Foams are moist and absorbent, and they require a dressing to hold them in place. Alginates are used for deep cavities and sinuses. They are very Table 1 Classification of Pressure Ulcers (according to the National Pressure Ulcer Advisory Panel) SOURCE: National Pressure Ulcer Advisory Panel (NPUAP) absorptive and need a secondary dressing. Other agents used to treat pressure ulcers include growth factors, hyperbaric oxygen, skin grafts, and skin substitutes. In general, healing times are one to two weeks for Stage II and six weeks to three months for Stages III and IV.