Pressure ulcers are localized injuries to the skin and/or underlying tissue that usually occur over a bony prominence as a result of pressure, or pressure in combination with shear and/or friction. The most common sites are the sacrum, coccyx, heels or the hips, but other sites such as the elbows, knees, ankles or the back of the cranium can be affected.
Pressure ulcers occur due to pressure applied to soft tissue resulting in completely or partially obstructed blood flow to the soft tissue. Shear is also a cause, as it can pull on blood vessels that feed the skin. Pressure ulcers most commonly develop in persons who are not moving about or are confined to wheelchairs. It is widely believed that other factors can influence the tolerance of skin for pressure and shear, thereby increasing the risk of pressure ulcer development. These factors are protein-calorie malnutrition, microclimate (skin wetness caused by sweating or incontinence), diseases that reduce blood flow to the skin, such as arteriosclerosis, or diseases that reduce the sensation in the skin, such as paralysis or neuropathy. The healing of pressure ulcers may be slowed by the age of the person, medical conditions (such as arteriosclerosis, diabetes or infection), smoking or medications such as antiinflammatory drugs.
Although often prevented and treatable if detected early, pressure ulcers can be very difficult to prevent in critically ill patients, frail elders, wheelchair users (especially where spinal injury is involved) and terminally ill patients. Primary prevention is to redistribute pressure by turning the patient regularly. The benefit of turning to avoid further sores is well documented since at least the 19th century. In addition to turning and re-positioning the patient in bed or wheelchair, eating a balanced diet with adequate protein and keeping the skin free from exposure to urine and stool is very important. Source: Wikipedia