A pressure ulcer results when there is localized damage to the skin and underlying tissue as a result of compression between a bony prominence and an external surface. Damage is caused by the forces of pressure, shear, and friction acting individually or in combination with each other.
Pressure ulcers, previously termed decubitus ulcers, are also commonly referred to as pressure sores and bed sores. Common sites for pressure ulcer formation are the sacrum, over the ischial tuberosity, the trochanter, and the calcaneus. Other locations are the elbow, ankle, scapula, and the occiput. However, the most common sites are the sacrum and the heels. Pressure ulcers affect from 1.5 to 3 million people in the United States at an annual cost of approximately $5 billion.
Pressure ulcers occur more commonly in certain subsets of patients, such as elderly individuals (ie, those over the age of 70), patients who have had surgery for hip fracture, and patients with spinal cord injury. Patients in nursing homes or assisted living facilities or who are otherwise hospitalized are at increased risk for developing pressure ulcers.
Pressure ulcers are classified according to the extent of tissue damage per the National Pressure Ulcer Advisory Panel:
- Stage l: Skin is intact with an area of nonblanching erythema. This is usually over a bony prominence.
- Stage ll: Partial-thickness skin loss with loss of the epidermis and some of the dermis. It appears as a shallow ulcer with a red-pink color. No slough or necrotic tissue is present in the base. It may also appear as an enclosed or open serum-filled blister.
- Stage lll: Full-thickness loss of skin with the epidermis and dermis gone and damage to or necrosis of subcutaneous tissues. Damage extends down to but not through the underlying fascia. Subcutaneous fat may be visible, but muscle, tendon, or bone is not seen. Slough may be present but does not hinder estimation of the extent of tissue loss. Tunneling or undermining may be present.
- Stage lV: Full-thickness loss of skin with extensive destruction, tissue necrosis, and damage to bone, muscle, or other supporting structures that are exposed.
Two additional stages of pressure ulcer formation were added in 2007:
- Suspected Deep Tissue Injury: Area of localized discolored intact skin that is purple or maroon-red in color. It may also appear as a blood-filled blister resulting from damage to underlying soft tissue. Preceding skin changes may include skin that is painful, firm, boggy, or a different temperature compared with the surrounding skin.
- Unstageable Pressure Ulcers: Full-tissue thickness loss where the base of the ulcer is covered by slough or an eschar. The true depth of the damage cannot be determined until the necrotic tissue is cleared away or the eschar removed and the base of the pressure ulcer is visible. (Debridement should be avoided in the case of a stable eschar on the heels.)
Dark Skin Considerations:
Erythema can be subtle in darker skin and may appear as a slightly different color, or the skin may be slightly darker than normal. Discoloration, warmth, induration, or hardness of skin may be the only signs of a stage I ulcer in people with darker skin tones. Deep tissue injury may also be difficult to detect in patients with more deeply pigmented skin.