What is the standard classification system for grading bed sores (pressure ulcers)?

Standard Classification System for Pressure Ulcers (Bed Sores)

The National Pressure Ulcer Advisory Panel (NPUAP) staging system is the standard classification system for grading pressure ulcers (bed sores), which categorizes pressure injuries into 4 main stages based on tissue involvement depth, with additional categories for unstageable pressure injuries and deep tissue pressure injuries.

NPUAP Pressure Ulcer Staging System

Stage 1: Non-blanchable Erythema

• Intact skin with localized area of non-blanchable erythema
• May appear differently in darkly pigmented skin
• Area may be painful, firm, soft, warmer or cooler compared to adjacent tissue
• May indicate "at risk" persons

Stage 2: Partial Thickness Skin Loss

• Partial-thickness loss of dermis
• Presents as a shallow open ulcer with a red-pink wound bed, without slough
• May also present as an intact or open/ruptured serum-filled blister
• Does not include skin tears, tape burns, incontinence-associated dermatitis, or excoriation

Stage 3: Full Thickness Skin Loss

• Full-thickness tissue loss
• Subcutaneous fat may be visible but bone, tendon, or muscle are not exposed
• Slough may be present but does not obscure the depth of tissue loss
• May include undermining and tunneling
• Depth varies by anatomical location

Stage 4: Full Thickness Tissue Loss

• Full-thickness tissue loss with exposed bone, tendon, or muscle
• Slough or eschar may be present on some parts of the wound bed
• Often includes undermining and tunneling
• Depth varies by anatomical location

Additional Categories:

• Unstageable Pressure Injury: Full-thickness skin and tissue loss in which the base of the ulcer is covered by slough or eschar, making accurate staging impossible until removed
• Deep Tissue Pressure Injury: Purple or maroon localized area of discolored intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear

Alternative Classification Systems

While the NPUAP system is the standard, several other classification systems exist for specific contexts:

SINBAD System

Used primarily for diabetic foot ulcers 1, this system grades:

• Site (forefoot vs. midfoot/hindfoot)
• Ischemia (pedal blood flow)
• Neuropathy (protective sensation)
• Bacterial infection
• Area (ulcer size)
• Depth (tissue involvement)

Wagner Classification

One of the oldest systems 1, with grades ranging from 0-5:

• Grade 0: Pre- or post-ulcerative site
• Grade 1: Superficial ulcer
• Grade 2: Ulcer penetrating to tendon or joint capsule
• Grade 3: Deep wound with abscess, osteomyelitis, or joint sepsis
• Grade 4: Forefoot gangrene
• Grade 5: Whole foot gangrene

University of Texas (UT) Classification

A matrix system with 4 grades (depth) and 4 stages (presence/absence of infection or ischemia) 1.

Clinical Application

When assessing pressure ulcers:

1. Thoroughly clean the wound to allow proper visualization
2. Measure the wound dimensions (length, width, depth)
3. Assess for tunneling or undermining
4. Document the wound bed characteristics (granulation, slough, eschar)
5. Evaluate surrounding skin for erythema, maceration, or induration
6. Assess for signs of infection

Common Pitfalls in Pressure Ulcer Classification

• Mistaking moisture-associated skin damage for Stage 2 pressure ulcers
• Attempting to stage wounds covered with eschar or slough (these should be classified as "unstageable")
• Reverse staging (incorrectly documenting healing ulcers as moving backward in stages)
• Failing to differentiate between a healing Stage 3/4 ulcer and a new Stage 2 ulcer
• Not accounting for anatomical differences when assessing depth (e.g., areas with little adipose tissue)

Risk Assessment

The Braden Scale is commonly used for pressure ulcer risk assessment 2, evaluating six factors:

• Sensory Perception
• Moisture
• Activity
• Mobility
• Nutrition
• Friction and Shear

Scores ≤18 indicate increased risk, with lower scores representing higher risk.

By using standardized classification systems, healthcare providers can ensure consistent assessment, documentation, and appropriate treatment planning for pressure ulcers, ultimately improving patient outcomes and reducing morbidity associated with these wounds.