Pressure Injuries: Risk, Staging, and Prevention

1. What causes pressure injuries

A pressure injury is localized damage to skin and underlying soft tissue, usually over a bony prominence (sacrum, heels, elbows, hips) or related to a device. The main forces are pressure (body weight compressing tissue between bone and surface, reducing tissue perfusion — the blood flow that delivers oxygen), shear (skin staying in place while deeper tissue slides, kinking vessels), friction (rubbing that damages the surface), and moisture (prolonged wetness softening the skin). Highest risk falls on people with limited mobility or sensation, poor perfusion or nutrition, or who are very thin or very heavy.

2. Risk assessment

Because most pressure injuries are preventable, the nurse screens risk on admission and whenever condition changes. The Braden Scale scores six areas — sensory perception, moisture, activity, mobility, nutrition, and friction/shear — with lower totals meaning higher risk. The Norton Scale scores five areas — physical condition, mental condition, activity, mobility, and incontinence. These tools standardize risk assessment and prompt prevention, but they are only part of clinical judgment; a person with a critical low area (such as immobility) still needs intensive prevention even if the total score looks moderate.

3. Staging and prevention

Staging describes the depth of visible damage and requires qualified clinical evaluation. Stage 1: intact skin with non-blanchable redness. Stage 2: partial-thickness loss — an intact or ruptured blister or shallow pink-red open area, no slough. Stage 3: full-thickness loss with visible fat, but no exposed bone, tendon, or muscle. Stage 4: full-thickness loss with exposed bone, tendon, or muscle. Unstageable: full-thickness loss covered by slough or eschar, so depth cannot be determined until a qualified clinician removes it. Deep-tissue pressure injury (DTPI): persistent deep red, maroon, or purple discoloration or a blood-filled blister — deeper damage beneath what is visible.

Prevention is the priority and is largely independent nursing work: repositioning people who cannot move themselves (using lift or slide devices to avoid friction and shear); support surfaces such as specialized mattresses, overlays, cushions, and heel off-loading; nutrition (adequate protein, calories, and hydration); moisture management (keeping skin clean, dry, and protected from incontinence); regular skin inspection of bony prominences and areas under devices, mindful that early redness may look different on darker skin tones; device-related padding and repositioning of tubes and other devices; and timely, factual documentation of risk scores, skin findings, and interventions.

How it works

1. Prolonged or intense pressure squeezes vessels, reducing perfusion so cells become starved and damaged.
2. Shear and friction add surface and deep damage; moisture weakens skin, worsening all forces.
3. The nurse screens risk with the Braden or Norton scale and inspects skin to catch reversible changes early.
4. Prevention is applied: repositioning, support surfaces, nutrition, moisture management, and device protection.
5. If injury occurs, its depth is described by staging, and the nurse documents, communicates, and escalates.
6. Ongoing reassessment and documentation confirm whether prevention is working or the plan must change.

Common confusions

Memory aids

Remember the forces as "PSFM — Pressure Squeezes, Shear Slides, Friction Rubs, Moisture Melts." For staging: "1 red, 2 shallow, 3 fat, 4 deep (bone), and two unknowns — Unstageable and Deep."

Quick review

Topic Recap

• A pressure injury is localized skin and tissue damage, usually over a bony prominence, caused by pressure that reduces perfusion — worsened by shear, friction, and moisture.
• The Braden and Norton scales standardize risk assessment; lower scores indicate higher risk.
• Staging runs from Stage 1 (non-blanchable redness) through Stage 4 (exposed bone, tendon, or muscle), plus unstageable and deep-tissue pressure injury when depth or extent is hidden.
• Prevention — repositioning, support surfaces, nutrition, moisture management, skin inspection, and device protection — is the highest priority and largely independent nursing work.
• Documentation, communication, and escalation are essential because most pressure injuries are preventable.

Knowledge Check

1. What four mechanical forces contribute to pressure injuries?
2. What does the Braden Scale measure, and what does a lower score indicate?
3. How does a Stage 1 pressure injury differ from a Stage 2?
4. What makes an injury unstageable, and why does that matter?
5. Name four prevention strategies the nurse can implement.

Answers and Rationales

1. Answer: Pressure, shear, friction, and moisture. Why: Pressure reduces perfusion; shear and friction damage tissue; moisture weakens skin.
2. Answer: The Braden Scale scores sensory perception, moisture, activity, mobility, nutrition, and friction/shear; lower scores mean higher risk. Why: A low score in critical areas prompts more intensive prevention.
3. Answer: Stage 1 is intact skin with non-blanchable redness; Stage 2 is partial-thickness loss with a blister or shallow open area. Why: Stage 1 has not broken the surface; Stage 2 has.
4. Answer: Unstageable means the base is covered by slough or eschar, so depth cannot be determined until a qualified clinician removes it. Why: You cannot stage what you cannot see; premature staging risks underestimating severity.
5. Answer: Any four of repositioning, support surfaces, nutrition, moisture management, skin inspection, or device protection. Why: Each addresses a force or risk factor that causes or worsens injury.