Pressure Ulcers

Pressure ulcers, also known as pressure sores, bed sores, or pressure injuries, are localised damage to the skin and underlying tissue, typically over bony prominences. They result from prolonged pressure, shear, or friction. Common sites include the skin over the sacrum, coccyx, heels, and hips, although other areas such as the elbows, knees, ankles, shoulders, and the back of the head may also be affected.

Signs & Symptoms

Pressure ulcers are characterised by localised skin damage and can progress through several stages:

• Stage 1: Intact skin with non-blanchable redness.
• Stage 2: Partial thickness loss of dermis presenting as a shallow open ulcer.
• Stage 3: Full thickness tissue loss with visible subcutaneous fat but no bone, tendon, or muscle exposure.
• Stage 4: Full thickness tissue loss with exposed bone, tendon, or muscle.

Complications

Pressure ulcers can lead to severe complications such as infection, autonomic dysreflexia, bladder distension, bone infection (osteomyelitis), sepsis, amyloidosis, anaemia, and in rare cases, malignant transformation (Marjolin's ulcer). These complications can be life-threatening, with kidney failure and amyloidosis being common causes of death.

Causes

Pressure ulcers develop due to a combination of factors:

1. External pressure: Prolonged pressure over bony areas can obstruct blood flow, leading to ischaemia and necrosis.
2. Friction: Rubbing of the skin against surfaces can damage superficial blood vessels.
3. Shearing: Skin and underlying tissues move in opposite directions, causing tissue separation and damage.
4. Moisture: Excessive moisture from sweating, urine, or wound drainage can exacerbate skin damage.

Risk Factors

Over 100 risk factors contribute to the development of pressure ulcers, including immobility, diabetes mellitus, peripheral vascular disease, malnutrition, cerebrovascular accidents, hypotension, age over 70, smoking, dry skin, low body mass index, incontinence, and the use of physical restraints.

Pathophysiology

Pressure ulcers result from impaired blood supply leading to ischaemia and subsequent tissue damage. Muscle cells are particularly vulnerable, and deep tissue injuries can occur without visible skin damage.

Diagnosis

Classification

Pressure ulcers are classified into stages based on the depth of tissue injury:

• Stage 1: Non-blanchable redness.
• Stage 2: Partial thickness skin loss.
• Stage 3: Full thickness tissue loss with visible fat.
• Stage 4: Full thickness tissue loss with exposed bone, tendon, or muscle.
• Unstageable: Full thickness tissue loss obscured by slough or eschar.
• Deep Tissue Pressure Injury: Persistent non-blanchable deep red, maroon, or purple discolouration.

Prevention

Prevention strategies include regular repositioning to redistribute pressure, use of support surfaces like specialised mattresses and cushions, maintaining skin hygiene, and ensuring proper nutrition. Risk assessment tools such as the Braden Scale help in identifying individuals at higher risk.

Treatment

Debridement

Necrotic tissue removal is very important and can be achieved through various methods:

• Autolytic debridement: Use of moist dressings.
• Biological debridement: Use of medical maggots.
• Chemical debridement: Application of prescribed enzymes.
• Mechanical debridement: Use of debriding dressings or whirlpool.
• Surgical debridement: Removal by a surgeon.

Dressings

Appropriate dressings are selected based on the wound characteristics. Foam dressings, hydrocolloid dressings, and antimicrobial dressings are commonly used.

Other Treatments

Additional treatments include negative pressure wound therapy, reconstructive surgery, and nutritional support. The effectiveness of many treatments remains uncertain, highlighting the need for further research.

Epidemiology

Pressure ulcers affect millions globally, with prevalence rates varying across different care settings. In the UK, the prevalence in hospitals ranges from 8.3% to 23%. The condition is more common in intensive care units due to patient immobility and compromised immune systems.

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Self-assessment MCQs (single best answer)

Which of the following is NOT a common site for pressure ulcers?

Stage I pressure ulcers are characterised by:

Which of the following is a complication of pressure ulcers that can be life-threatening?

Which factor is NOT a cause of pressure ulcers?

Which stage of pressure ulcer is described as full thickness tissue loss with visible subcutaneous fat but no bone, tendon, or muscle exposure?

The Braden Scale is used for:

Which debridement method uses medical maggots?

Which of the following is NOT a risk factor for developing pressure ulcers?

What characterises a deep tissue pressure injury?

What is the prevalence range of pressure ulcers in hospitals in the UK?