life

The terms decubitus ulcer and pressure sore often are used interchangeably in the medical community. Decubitus, from the Latin decumbere, means "to lie down." Decubitus ulcer, therefore, does not adequately describe ulceration that occurs in other positions, such as prolonged sitting (eg, the commonly encountered ischial tuberosity ulcer). Because the common denominator of all such ulcerations is pressure, pressure sore is the better term to describe this condition.

Many factors contribute to the development of pressure sores, but pressure leading to ischemia is the final common pathway. Tissues are capable of withstanding enormous pressures when brief in duration, but prolonged exposure to pressures slightly above capillary filling pressure initiates a downward spiral towards ulceration.

Impaired mobility is an important contributing factor. Patients who are neurologically impaired, heavily sedated, restrained, or demented are incapable of assuming the responsibility of altering their position to relieve pressure. Moreover, this paralysis leads to muscle and soft tissue atrophy, decreasing the bulk over which these bony prominences are supported.

Contractures and spasticity often contribute by repeatedly exposing tissues to pressure through flexion of a joint. Contractures rigidly hold a joint in flexion, while spasticity subjects tissues to considerable repeated friction and shear forces.

Sensory loss also contributes to ulceration by removing one of the most important warning signals, pain.

Paralysis and insensibility also lead to atrophy of the skin with thinning of this protective barrier. The skin becomes more susceptible to minor traumatic forces, such as friction and shear forces, exerted during the moving of a patient. Trauma causing deepithelialization leads to transdermal water loss, creating maceration and adherence of the skin to clothing and bedding, which raises the coefficient of friction for further insult.

Malnutrition, hypoproteinemia, and anemia reflect the overall status of the patient and can contribute to vulnerability of tissue and delays in wound healing. Poor nutritional status certainly contributes to the chronicity often observed with these lesions. Anemia indicates poor oxygen-carrying capacity of the blood. Vascular disease also may impair blood flow to the region of ulceration.

Bacterial contamination from improper skin care or urinary or fecal incontinence, while not truly an etiological factor, is an important factor to consider in the treatment of pressure sores and can delay wound healing.