Key Facts

Pressure ulcers are a significant cause of morbidity, pain, and reduced quality of life. Prevention is far more effective and cost-effective than treatment.

Epidemiology

• ~700,000 affected per year in UK
• Prevalence: 4-10% of hospital patients; up to 30% in care homes
• Annual NHS cost: ~£3.8 billion (accounts for 4% of total NHS expenditure)
• Category 2 and above are reportable as clinical incidents

Aetiology

• Sustained pressure over bony prominence: exceeds capillary closing pressure (~32mmHg) → tissue ischaemia → necrosis
• Shear forces: layers of tissue slide against each other (e.g. sliding down in bed)
• Friction: skin dragged across surface
• Moisture: maceration from incontinence or perspiration

Pathophysiology

• Pressure > capillary closing pressure → microvascular occlusion → tissue hypoxia → ischaemia-reperfusion injury → cellular death → ulceration
• Necrosis occurs from deep tissues outward ("iceberg" phenomenon — visible damage often underestimates deep tissue injury)
• Reperfusion injury on release of pressure: reactive hyperaemia (blanching normal; non-blanchable = tissue damage)
• Biofilm formation in chronic wounds impairs healing

Category Classification (EPUAP/NPUAP)

• Category 1: Non-blanchable erythema of intact skin
• Category 2: Partial-thickness skin loss (dermis exposed); shallow open ulcer or blister
• Category 3: Full-thickness skin loss (subcutaneous fat visible; bone/tendon NOT visible)
• Category 4: Full-thickness tissue loss (bone, tendon, or muscle exposed)
• Unstageable: obscured by slough or eschar (cannot assess depth)
• Deep tissue injury: purple/maroon localised area; intact skin with underlying damage

Common Sites

• Sacrum (most common)
• Heels
• Ischial tuberosities (wheelchair users)
• Greater trochanters
• Occiput (ICU patients)
• Malleoli

Red Flags

• Signs of infection: increasing pain, warmth, erythema, purulent exudate, fever, rising CRP
• Osteomyelitis (deep-probing bone)
• Cellulitis spreading from ulcer
• Rapid deterioration in wound
• Sepsis from infected pressure ulcer

Bedside

• Risk assessment: Waterlow score (≥10 at risk) or Braden scale (≤18 at risk)
• Skin assessment: colour, temperature, moisture, integrity (especially over bony prominences)
• Wound assessment: size (measure length/width/depth), category, bed tissue type (granulation, slough, eschar, necrotic), exudate, odour, edges, surrounding skin
• Nutritional assessment (MUST score)
• Mobility assessment
• Continence assessment

Bloods

• FBC, CRP (infection markers)
• Albumin (nutritional status/healing capacity)
• HbA1c (diabetic control)
• Blood cultures (if sepsis suspected)

Imaging

• X-ray/MRI: if osteomyelitis suspected (probe-to-bone test positive)

Special Tests

• Wound swab (only if clinical signs of infection — not routine)
• Tissue biopsy: if non-healing/malignant change suspected
• ABPI: if arterial component suspected

Non-pharmacological

• Prevention (SSKIN bundle):
  • Surface: pressure-relieving mattress/cushion (alternating pressure, static foam)
  • Skin inspection: at least daily; document findings
  • Keep moving: reposition every 2 hours (30° tilt); encourage mobilisation
  • Incontinence: manage promptly; barrier cream
  • Nutrition: optimise diet; refer to dietitian if malnourished
• Wound management:
  • Debridement of necrotic tissue (autolytic, sharp, or larval)
  • Appropriate dressings: maintain moist wound environment (foam, hydrocolloid, alginate depending on exudate)
  • Offloading devices (heel elevation, heel-specific devices)
• Patient education: repositioning techniques, skin care

Pharmacological

• Analgesia: paracetamol; topical lidocaine for dressing changes
• Antibiotics: only if clinical signs of infection (cellulitis, purulent discharge, systemic sepsis)
  • Flucloxacillin 500mg-1g QDS (or clarithromycin if penicillin-allergic)
  • Broad-spectrum if severe/deep infection: co-amoxiclav, piperacillin-tazobactam
• Nutritional supplementation: protein-rich ONS, vitamin C, zinc (limited evidence but commonly supplemented)

Surgical/Interventional

• Surgical debridement: for extensive necrosis/eschar
• Negative pressure wound therapy (VAC): for large/deep wounds; promotes granulation
• Reconstructive surgery: flap reconstruction for large Category 3-4 ulcers (in selected patients)

Referral Criteria

• Category 3 or 4: tissue viability specialist nurse
• Suspected osteomyelitis: orthopaedic/surgical review
• Non-healing wound: tissue viability team, wound biopsy
• All pressure ulcers: clinical incident reporting (Datix)

• Category 1-2: usually heal with appropriate care (weeks)
• Category 3-4: prolonged healing (months); may never fully heal in frail patients
• Mortality: patients who develop pressure ulcers in hospital have 4× mortality (associated with severity of illness)
• Osteomyelitis complicates up to 20% of Category 4 ulcers (difficult to treat)
• Prevention is far more effective than treatment
• Recurrence rate is high if underlying risk factors not addressed

EPUAP/NPUAP Pressure Ulcer Categories

Waterlow Score Risk Categories