– Ischemic necrosis and ulceration of tissues that overlie a bony prominence and that have been subjected to prolonged external pressure from a supporting surface such as a bed or wheelchair.
Causes and Incidence
Decubiti are caused by prolonged pressure on tissues compressed between an internal body structure, such as bone, and an external surface. The force and duration of the pressure directly determine the size of the ulcer. Contributing factors include immobilization, sensory and motor deficits, reduced circulation, malnutrition, anemia, edema, infection, friction, moisture, incontinence, shearing forces, decreased tissue integrity or viability, and aging.
Pressure exerted over an area interferes with the blood supply to the tissue, producing ischemia and increasing capillary pressure. This leads to edema and multiple small-vessel thromboses and sets up an inflammatory reaction. If the pressure is not relieved, the ischemic tissue necroses and ulcerates.
Decubitus formation has six definable stages with characteristic signs and symptoms.
Redness that blanches with pressure; skin is warm and soft to the touch
Redness, edema, and induration; skin often abraded or blistered
Breaks in the skin as it becomes necrotic; exposure of subcutaneous tissue; drainage from wound
Necrosis extends to subcutaneous tissue; drainage is foul smelling and yellow
Necrosis extends through fat to muscle; wound may develop a black, leathery eschar around the edges; drainage is greenish
Necrosis extends to bone; deep tunnels form in fat and muscle; body cavities (e.g., rectum or bladder) are eroded; bone is destroyed through periostitis and osteitis
Bacteremia and septicemia are common complications. Osteomyelitis, septic arthritis, and pathologic fractures also can occur.
Clinical evaluation revealing the characteristic picture described under Clinical Manifestations; history of one or more predisposing and contributing factors.
Stages 4-6: debridement and closure; skin grafting, skin flaps, muscle flaps; joint disarticulation may be required with large stage 5 or stage 6 ulcers.
Topical applications (e.g., enzymatic ointments) to debride necrotic tissue, hydrophilic gels for reepithelialization; topical antibiotics for debridement and to suppress infection; platelet-derived epidermal growth factors for tissue healing.
Elimination of pressure through frequent turning, special beds, mattress overlays, and wheelchair pads filled with gels, air, water, sand, or other pressurerelieving ingredients; use of lifting devices to prevent shearing; debridement with wetdry dressings; irrigation with whirlpool baths; electrical stimulation to promote antibacterial effect and stimulate muscle protein synthesis; balanced nutrition; control of incontinence and careful cleansing; instruction in ulcer prevention: frequent use of pressure relief measures (turning, raising off buttocks, weight shifts when seated); daily skin inspections; use of pressure relief mattress overlays and wheelchair cushions; clean, dry clothing and bed linens free of wrinkles and treated with fabric softener; lotion on all skin surfaces, especially over bony prominences, to reduce friction.