Clinical meaning
The National Pressure Ulcer Advisory Panel (NPUAP) classification system stages pressure injuries based on the depth of tissue destruction. Stage 1 is intact skin with non-blanchable erythema (the area does not whiten when pressed, indicating capillary bed damage and inflammatory response to sustained pressure). Stage 2 involves partial-thickness skin loss with exposed dermis, appearing as a shallow open ulcer with a red-pink wound bed, or an intact or ruptured serum-filled blister. Stage 3 is full-thickness skin loss with subcutaneous fat visible but bone, tendon, and muscle not exposed; undermining and tunneling may be present. Stage 4 is full-thickness tissue loss with exposed bone, tendon, cartilage, or muscle; osteomyelitis risk is significant. Unstageable injuries have the wound bed obscured by slough (yellow, tan, gray) or eschar (black) preventing depth determination. Deep tissue pressure injury (DTPI) presents as a persistent non-blanchable deep red, maroon, or purple discoloration or blood-filled blister, representing damage to underlying tissue from sustained pressure and shear that has not yet fully manifested at the surface. The nurse assesses all pressure points every shift, implements evidence-based prevention (repositioning every 2 hours, pressure redistribution surfaces, moisture management, nutrition optimization with adequate protein and vitamin C), documents staging accurately, selects appropriate wound care based on stage, and monitors for healing progression using wound measurement tools.