Pressure Injury Stages

What a pressure injury is

A pressure injury is localized damage to the skin and the soft tissue beneath it. It usually forms over a bony prominence, such as the sacrum, heels, hips or back of the head, or under a medical or other device. It results from strong or prolonged pressure, or pressure combined with shear. The skin may stay intact or open into an ulcer, and the injury may be painful.

In 2016 the panel, then called NPUAP, replaced the term pressure ulcer with pressure injury, switched from Roman to Arabic numerals, and dropped the word suspected from deep tissue pressure injury. Many facilities and billing codes still use pressure ulcer, so you will see both terms.

The definitions below are paraphrased. The official NPIAP wording and illustrations are copyrighted; use the NPIAP materials for formal education and audits.

Pressure injury staging chart

Stage by the deepest tissue you can see or feel. If slough or eschar hides the base, the injury is unstageable until the base is visible.

Stages 1 and 2: skin intact or partial thickness

Stage 1: The skin is intact, but a localized area stays red when you press on it. In darkly pigmented skin the redness may not be visible, so check for changes in temperature, firmness, swelling or pain compared with nearby skin. These changes can appear before any color change. If the area is purple or maroon, suspect a deep tissue pressure injury instead.

Stage 2: The top layer of skin is lost and the dermis is exposed. The wound bed is viable, pink or red and moist. It can also look like a blister filled with clear fluid, intact or broken. You should not see fat, granulation tissue, slough or eschar. Do not use Stage 2 for moisture-associated skin damage such as incontinence dermatitis, intertrigo, medical adhesive skin injury, skin tears, burns or abrasions.

Stages 3 and 4: full-thickness tissue loss

Stage 3: The full thickness of skin is lost and fat is visible in the ulcer. Granulation tissue and rolled wound edges (epibole) are often present, and slough or eschar may be seen in part of the bed. Depth depends on the location: the bridge of the nose or the ear can have a shallow Stage 3, while the sacrum can be deep. Undermining and tunneling may occur. Fascia, muscle, tendon, ligament, cartilage and bone are not exposed.

Stage 4: Full-thickness skin and tissue loss with fascia, muscle, tendon, ligament, cartilage or bone that you can see or feel directly in the ulcer. Slough or eschar may be present, and epibole, undermining and tunneling are common. Bone involvement raises the risk of osteomyelitis.

Unstageable and deep tissue pressure injury

Unstageable: The wound is full thickness, but slough (yellow, tan, gray or green) or eschar (brown or black, often leathery) covers the base, so you cannot tell how deep it goes. Once the covering is removed, it will prove to be Stage 3 or Stage 4. Stable eschar on the heel or on an ischemic limb, meaning dry, adherent and intact without redness or fluctuance, should not be softened or removed.

Deep tissue pressure injury (DTPI): Intact or broken skin shows a localized area of persistent deep red, maroon or purple discoloration that does not blanch, or the epidermis separates to reveal a dark wound bed or a blood-filled blister. Pain and temperature change often come first. The area may evolve quickly to show the real extent of damage or may resolve without tissue loss. Do not use this label for vascular, traumatic, neuropathic or dermatologic conditions.

Medical device-related and mucosal membrane pressure injuries

Medical device-related pressure injury: This label describes the cause, not a stage. The injury comes from a device used for diagnosis or treatment, such as an oxygen mask or nasal cannula, endotracheal tube holder, cervical collar, splint, catheter or tubing. The damage usually matches the shape of the device. Stage it with the standard staging system.

Mucosal membrane pressure injury: Found on a mucous membrane, such as the lips, tongue, nostril lining or urethra, where a medical device has been in place. Because of the anatomy of mucosal tissue, these injuries cannot be staged.

Nursing actions for pressure injuries

Prevention starts with risk assessment. The Braden Scale scores sensory perception, moisture, activity, mobility, nutrition, and friction and shear; a score of 18 or less generally flags risk. Reassess risk and inspect the skin on admission, on a regular schedule and whenever the patient's condition changes.

• Inspect the skin head to toe, including under every device, at least daily and per facility policy
• Reposition on a schedule tailored to the patient and support surface, and float the heels off the bed
• Use pressure-redistributing mattresses and cushions for at-risk patients
• Manage moisture from incontinence, sweat and wound drainage; keep skin clean and dry
• Pad and reposition devices where possible, and check the skin beneath them
• Screen nutrition and hydration and involve the dietitian when intake is poor
• Document location, stage, size (length x width x depth), wound bed, exudate, odor, wound edges and pain
• Report any new injury, worsening wound or signs of infection, and follow your wound care team's plan

Do not reverse-stage. A healing Stage 4 is documented as a healing Stage 4, not as a Stage 3 or 2.