Pressure Ulcers

Pressure ulcers, commonly called pressure sores or bedsores, are localized areas of cellular necrosis that occur most often in the skin and subcutaneous (S.C.) tissue over bony prominences. These ulcers may be superficial, caused by local skin irritation with subsequent surface maceration, or deep, originating in underlying tissue. Deep lesions often go undetected until they penetrate the skin; but, by then, they've usually caused S.C. damage.

Causes

Most pressure ulcers are caused by pressure, particularly over bony prominences, that interrupts normal circulatory function, leading to ischemia of the underlying structures of skin, fat, and muscles. The intensity and duration of such pressure govern the severity of the ulcer; pressure exerted over an area for a moderate period (1 to 2 hours) produces tissue ischemia and increased capillary pressure, leading to edema and multiple small vessel thromboses. An
inflammatory reaction gives way to ulceration and necrosis of ischemic cells. In turn, necrotic tissue predisposes to bacterial invasion and subsequent infection.

The patient's position determines the pressure exerted on the tissues. For example, if the head of the bed is elevated, or the patient assumes a slumped position, gravity pulls his weight downward and forward. This shearing force causes deep ulcers due to ischemic changes in the muscles and S.C. tissues, and occurs most often over the sacrum and ischial tuberosities.

Predisposing conditions for pressure ulcers include altered mobility, inadequate nutrition (leading to weight loss and subsequent reduction of S.C. tissue and muscle bulk), and a breakdown in skin or S.C. tissue (as a result of edema, incontinence, fever, pathologic conditions, or obesity).

Signs and symptoms

Pressure ulcers commonly develop over bony prominences. Early features of superficiallesions are shiny, erythematous changes over the compressed area, caused by localized vasodilation when pressure is relieved. Superficial erythema progresses to small blisters or erosions and, ultimately, to necrosis and ulceration.

An inflamed area on the skin's surface may be the first sign of underlying damage when pressure is exerted between deep tissue and bone. Bacteria in a compressed site cause inflammation and, eventually, infection, which leads to further necrosis. A foul-smelling, purulent discharge may seep from a lesion that penetrates the skin from beneath. Infected, necrotic tissue prevents healthy granulation of scar tissue; a black eschar may develop around and over the lesion.

Diagnosis

Pressure ulcers are obvious on physical examination. Wound culture and sensitivity testing of the exudate in the ulcer identify infecting organisms and antibiotics that may be needed. If severe hypoproteinemia is suspected, total serum protein values and serum albumin studies may be appropriate.

Treatment

Successful treatment must relieve pressure on the affected area, keep the area clean and dry, and promote healing.

Prevention

If bedridden or immobile with diabetes, circulation problems, incontinence, or mental disabilities, you should be checked for pressure sores every day. Look for reddened areas that, when pressed, do not turn white. Also look for blisters, sores, or craters. In addition, take the following steps:

• Change position at least every two hours to relieve pressure.
• Use items that can help reduce pressure -- pillows, sheepskin, foam padding, and powders from medical supply stores.
• Eat healthy, well-balanced meals.
• Exercise daily, including range-of-motion exercises for immobile patients.
• Keep skin clean and dry. Incontinent people need to take extra steps to limit moisture.