14.3 Pressure Injury Prevention, Staging & Advanced Wound Dressings

Pressure Injury Prevention, Staging & Advanced Wound Dressings

Pressure injuries (PIs) are critical nursing-sensitive quality indicators across Singapore acute hospitals, community hospitals, and nursing homes. Preventing hospital-acquired pressure injuries (HAPIs) requires systematic risk assessment, evidence-based skin care bundles, accurate anatomical staging, and advanced wound management based on tissue physiology and exudate dynamics.

Pressure Injury Etiology and Risk Stratification

A pressure injury is localized damage to the skin and underlying soft tissue, usually over a bony prominence or related to a medical or other device. The condition arises from intense or prolonged pressure, or pressure combined with shear. Shear forces occur when skin remains stationary against a surface while deeper tissue layers slide, compressing microvascular blood supply and leading to tissue ischemia, cell death, and necrosis.

Risk Assessment: The Braden Scale

In Singapore clinical protocols, skin and pressure injury risk assessment must be documented within 2 hours of admission using the Braden Scale for Predicting Pressure Sore Risk. The scale evaluates six subscales:

1. Sensory Perception (1–4): Ability to respond meaningfully to pressure-related discomfort.
2. Moisture (1–4): Degree to which skin is exposed to moisture (sweat, urine, exudate).
3. Activity (1–4): Degree of physical activity (bedfast to walks frequently).
4. Mobility (1–4): Ability to change and control body position.
5. Nutrition (1–4): Usual food intake pattern.
6. Friction and Shear (1–3): Amount of assistance required in moving and sliding.

Total scores range from 6 to 23:

• 15 – 18: Mild Risk (Initiate preventive turning schedule and barrier cream).
• 13 – 14: Moderate Risk (Apply alternating pressure mattress, position wedges).
• 10 – 12: High Risk (Mandatory q2h turning, floating heels, nutritional consult).
• ≤ 9: Very High Risk (Advanced pressure-relieving surfaces, continuous skin monitoring).

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Staging System (NPUAP / EPUAP / PPPIA Guidelines)

Nurses stage pressure injuries according to international consensus guidelines established by the National Pressure Injury Advisory Panel (NPUAP), European Pressure Ulcer Advisory Panel (EPUAP), and Pan Pacific Pressure Injury Alliance (PPPIA).

Stage 1: Non-Blanchable Erythema

Intact skin with a localized area of non-blanchable erythema. Darkly pigmented skin may not show visible blanching; its color may differ from the surrounding area (purplish/bluish tones), with local temperature changes, edema, or tissue firmness.

Stage 2: Partial-Thickness Skin Loss with Exposed Dermis

Partial-thickness loss of skin with exposed dermis. The wound bed is viable, pink or red, moist, and may present as an intact or ruptured serum-filled blister. Adipose tissue and deeper tissues are not visible. Granulation tissue, slough, and eschar are absent.

Stage 3: Full-Thickness Skin Loss

Full-thickness loss of skin, in which adipose (fat) is visible in the ulcer, and granulation tissue and epibole (rolled wound edges) are often present. Slough and/or eschar may be visible. Undermining and tunneling may occur. Fascia, muscle, tendon, ligament, cartilage, and bone are not exposed.

Stage 4: Full-Thickness Skin and Tissue Loss

Full-thickness skin and tissue loss with exposed or directly palpable fascia, muscle, tendon, ligament, cartilage, or bone in the ulcer. Slough and/or eschar may be visible. Epibole, undermining, and/or tunneling often occur. High risk for osteomyelitis and systemic sepsis.

Unstageable Pressure Injury: Obscured Full-Thickness Skin and Tissue Loss

Full-thickness skin and tissue loss in which the extent of tissue damage within the ulcer cannot be confirmed because it is obscured by slough or eschar. If slough or eschar is removed, a Stage 3 or Stage 4 pressure injury will be revealed. Crucial Clinical Rule: Stable, dry, intact eschar on the heels (without erythema or fluctuance) serves as the body's natural cover and should not be removed or debrided.

Deep Tissue Injury (DTI): Persistent Non-Blanchable Deep Red, Maroon, or Purple Discoloration

Intact or non-intact skin with localized area of persistent non-blanchable deep red, maroon, or purple discoloration, or epidermal separation revealing a dark wound bed or blood-filled blister. Wound may evolve rapidly to reveal the extent of tissue injury.

Differential Diagnosis: Incontinence-Associated Dermatitis (IAD)

Nurses must differentiate pressure injuries from IAD (a form of Moisture-Associated Skin Damage):

• Location: IAD occurs in perineal/perianal skin folds; PIs occur over bony prominences.
• Depth: IAD is superficial (epidermis/dermis); PIs extend into subcutaneous fat/muscle.
• Margins: IAD has diffuse, irregular edges with satellite lesions; PIs have distinct, circumscribed boundaries.

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Prevention Bundles & Singapore Nursing Protocols

Hospitals implement evidence-based PI prevention bundles:

• Repositioning Schedule: Reposition bedbound patients at least every 2 hours (30° lateral tilt position to relieve direct pressure on the sacrum and greater trochanter). Wheelchair-bound patients shift weight every 15 minutes.
• Heel Elevation: "Floating heels" off the mattress using specialized heel suspension boots or pillows placed under lower legs.
• Support Surfaces: Reactive foam mattresses for low/moderate risk; active alternating-pressure air mattresses for high risk.
• Nutritional Support: High-protein diet (1.2–1.5 g/kg body weight/day), supplemented with Vitamin C, Zinc, and L-arginine to promote collagen synthesis.
• Prophylactic Dressings: Applying multi-layer silicone foam dressings over the sacrum and heels to dissipate shear and friction forces.

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Advanced Wound Dressing Selection & TIME Framework

Wound bed preparation is structured using the TIME framework:

• T (Tissue Management): Debriding non-viable slough and eschar (autolytic using hydrogels, enzymatic using collagenase, or sharp surgical debridement).
• I (Infection/Inflammation Control): Assessing for critical colonization or biofilm using topical antimicrobials (silver, cadexomer iodine).
• M (Moisture Balance): Selecting dressings to maintain optimal moist wound healing without macerating surrounding skin.
• E (Edge Advancement): Managing rolled edges (epibole) and hypergranulation to allow epithelial migration.

Wound Dressing Selection Matrix

Infection control strictly adheres to National Centre for Infectious Diseases (NCID) guidelines, reserving systemic antibiotics for spreading cellulitis, bacteremia, or confirmed osteomyelitis.