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Pressure Ulcers (Pressure Sores)

Pressure ulcers develop at body-support interfaces over bony prominences as a result of external compression of the skin, shear forces, and friction, which produce ischemic tissue necrosis. Pressure ulcers occur in patients who are obtunded mentally or have diminished sensation (as in spinal cord disease) in the affected region. Secondary infection results in localized cellulitis, which can extend locally into bone or muscle or into the bloodstream with resultant bacteremia and sepsis.

Causes of Pressure Ulcers

External compression of the dermis and hypodermis leads to ischemic tissue damage and necrosis. Risk factors for developing pressure ulcers: inadequate nursing care, diminished sensation/immobility (obtunded mental status, spinal cord disease), hypotension, fecal or urinary incontinence, presence of fracture, hypoalbuminemia, and poor nutritional status. The mean skin capillary pressure is approximately 25 mmHg. External compression with pressures <30 mmHg occludes the blood vessels so that the surrounding tissues become anoxic. Amount of damage is proportional to extent and duration of pressure. Healthy individuals can tolerate higher pressures. Repositioning the patient every 1 or 2 h prevents the interface skin over a bony prominence from becoming ischemic, with subsequent ulcer formation. Secondary bacterial infection can enlarge the ulcer rapidly, extend to underlying structures (as in osteomyelitis), and invade the bloodstream, with bacteremia and septicemia. Infection also impairs or prevents healing.

Symptoms of Pressure Ulcers

A pressure sore may initially appear as a red area of skin that does not disappear after a few hours and it may feel tender. The area may become painful and purple in colour. Continued pressure and poor circulation cause the skin and tissue to break down.

An open sore may develop when an area of tissue dies. The sore may then become infected. In severe cases the sore increases in size and may cause destruction to muscle and bone underneath the skin.

Pressure sores are most common on the heels and on the hips. Other areas at risk for pressure sores include the base of the spine, the shoulder blades, the backs and sides of the knees, and the back of the head.

Diagnosis

Usually made clinically. Complications are assessed with data on cultures, biopsies, and imaging. Osteomyelitis occurs in nonhealing pressure ulcers; combination of elevated erythrocyte sedimentation rate, leukocytosis, and x-ray examination leads to diagnosis with 90% sensitivity and specificity.

Treatment

Prophylaxis in At-Risk Patients Reposition patient every 2 hour (more often if possible); massage areas prone to pressure ulcers while changing position of patient; inspect for areas of skin breakdown over pressure points.

• Use interface air mattress to reduce compression.
• Minimize friction and shear forces by using proper positioning, transferring, and turning techniques.
• Clean with mild cleansing agents, keeping skin free of urine and feces.
• Minimize skin exposure to excessive moisture from incontinence, perspiration, or wound drainage.
• Maintain head of the bed at a relatively low angle of elevation (<30 degrees).
• Evaluate and correct nutritional status; consider supplements of vitamin C and zinc.
• Mobilize patients as soon as possible.

Stages I and II Ulcers Topical antibiotics (not neomycin) under moist sterile gauze may be sufficient for early erosions. Normal saline wet­ to-dry dressings may be needed for debridement. If ulcer does not heal by 30% within 2 weeks, consider hydrogels or hydrocolloid dressings.

Stages III and IV Ulcers Surgical management includes: debridement of necrotic tissue, bony prominence removal, flaps and skin grafts.

Infectious Complications Continuous Osteomyelitis Prolonged course of antimicrobial agent depending on sensitivities, with or without surgical debridement of necrotic bone.

Transient Bacteremia Treatment is usually not indicated.

Sepsis Marked by elevated temperature, chills, hypotension, and tachycardia and/or tachypnea. Massive antibiotic treatment according to antibiogram.