In 2007, the National Pressure Ulcer Advisory Panel revised its previous staging scale to include Suspected Deep Tissue Injury and Unstageable Ulcers in addition to the previously described Stages I to IV:

Suspected deep tissue injury: purple or maroon localized area of discolored intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, and warmer or cooler as compared with adjacent soft tissue.

Stage I: intact skin with nonblanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area.

Stage II: partial-thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed, without slough; may also present as an intact or open/ruptured serum-filled blister.

Stage III: full-thickness tissue loss. Subcutaneous fat may be visible, but bone, tendon, or muscle is not exposed. Slough may be present but does not obscure the depth of tissue loss; may include undermining and tunneling.

Stage IV: full-thickness tissue loss with exposed bone, tendon, or muscle. Slough or eschar may be present on some parts of the wound bed; often includes undermining and tunneling.

Unstageable: full-thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green, or brown) and/or eschar (tan, brown, or black) in the wound bed. Unstageable ulcers may be restaged after debridement allows determination of the true extent of the wound.

Risk factors for development of a pressure ulcer include neurologic impairment due to decreased muscle tone, loss of muscle bulk, and diminished or absent sensorimotor abilities. Surgical patients are at risk during surgery from prolonged positioning and hypotensive anesthesia and postoperatively from immobility, sedative medications, and casts/splints. Other factors that contribute to the development of pressure ulcers, particularly in elderly patients, are impaired circulation, poor nutrition, and possibly impaired immune response. Maceration of the skin, usually due to incontinence, also significantly increases the risk of ulceration. Bed-ridden and wheelchair-bound patients are particularly vulnerable to the development of pressure ulcers.

A pressure ulcer requires intensive and costly long-term treatment. Therefore, aggressive intervention programs are essential to prevent or abort their formation, particularly in high-risk patients. The most effective means of prevention is the frequent repositioning of patients who are confined in bed, chair, or wheelchair. Position changes must occur every 2 hours to avoid continues excessive pressure over any single bony prominence. Vulnerable skin areas must be monitored frequently, and pressure on stage 1 lesions must be avoided to prevent further progression. For patients at risk for pressure ulcers, passive (or static) cushioning devices such as supersoft mattresses and wheelchair cushions made of foam, water, gel, or air-filled materials should be used; patients who are severely immobilized require active (or dynamic) pressure-relieving devices such as an alternating pressure, air fluidized, or air suspension mattress. Sedation should be avoided, incontinence controlled, and any nutritional deficiencies corrected in all immobile patients. Several studies have shown aggressive intervention applied by an effective multidisciplinary team can greatly reduce the incidence of pressure ulcers in hospitalized patients.