How to Recognize the 4 Stages of Pressure Injuries

April 26, 2017

Pressure Injuries can develop quickly and often add a layer of complication to already complex medical conditions. Read more to learn how to identify and diagnose patients with stage I, II, III, and IV pressure injuries.

Have you ever heard the expression, “When you’re green, you’re growing. When you’re ripe, you rot.”? Well, picture what happens when you leave a piece of fruit, a peach for instance, in a bowl on the counter. Somehow, over the course of the week you forget about it, and when you return to eat it, you pick it up, only to find one side of the peach flattened and turned to mush, the skin bruised and perhaps broken in some spots.

Our skin can react in much the same way, with a condition known as pressure injuries (also pressure ulcers or bedsores). Pressure injuries can add another layer of complication onto already complex medical treatments, but the good news is, they’re also relatively easy to spot and usually preventable, you just have to know what you’re looking for.

What exactly is a pressure injury?

A pressure injury is defined as an injury to the skin and underlying tissue resulting from prolonged pressure

They most often develop on skin that covers bony areas of the body, such as the heels, ankles, hips, and tailbone, and are most common in patients with limited mobility such as the elderly, nursing home patients, patients in a coma, patients with reduced pain perception, and any patients who cannot move specific parts of their body.

In 2016 the National Pressure Ulcer Advisory Panel (NPUAP) amended the official name from “pressure ulcer” to “pressure injury” to more accurately reflect the fact that open ulceration does not always occur, and pressure injuries can describe both intact or ulcerated skin.

What causes pressure injuries?

There are many contributing factors for pressure injuries. At the most basic level, they result from three primary factors:

  • Sustained pressure. When skin and underlying tissue experience prolonged contact against a surface, the pressure may lead to insufficient oxygenation and damaged cells. This happens most often to areas that lack sufficient padding from muscle or fat, like heels, hips, shoulder blades, elbows, and the tailbone.
  • Friction. Friction occurs when skin is dragged across a surface. For instance, when a patient changes position or a care provider moves them. Friction is exacerbated when skin is moist.
  • Shear. Shear occurs when two surfaces move in opposite directions; for example, when a hospital bed is elevated, a patient may slide down, pulling bones and skin in different directions.

Why is it important to recognize pressure injuries?

Certainly, the primary reason for wanting to recognize and treat pressure injuries when they occur is for optimal patient care, but there is a secondary reason that should reinforce vigilance for all medical practitioners. In 2013 the National Quality Forum declared pressure injuries a “never event." Specifically, they stated that stage 3 and 4 pressure injuries that occur after admission to a healthcare facility are unacceptable and (given the proper care) unnecessary. This inclusion as a “never event” brought with it financial implications for pressure injuries – in the simplest of terms, the Centers for Medicare and Medicaid Services ruled that they can deny Medicare payment for hospital-acquired conditions that fall under the category of “never events,” making pressure injuries costly in more ways than one. (For more on pressure injuries and never events, read this post.)

The Four Stages of Pressure Injuries

We know pressure injuries are dangerous for our patients and costly for our medical system, so the question becomes, how can we recognize them in order to guard against them? Pressure injuries are broken into four stages, where the stage indicates the extent of tissue damage. Following are the key indicators for each stage.

Stage 1 Pressure Injury: Non-blanchable erythema of intact skin

In stage 1 pressure injuries the skin is still intact with a localized area of redness that does not turn white when pressure is applied (also known as non-blanchable erythema). Stage 1 does not include purple or maroon discoloration; these may indicate deep tissue pressure injury. For visual reference, see illustrations of pressure injuries from the NPUAP here.  

Stage 2 Pressure Injury: Partial-thickness skin loss with exposed dermis

In stage 2 pressure injuries there is a partial-thickness loss of skin with exposed dermis. The wound bed is pink or red, moist, and may also present as an intact or ruptured serum-filled blister. Fat and deeper tissues are not visible. Connective granulation tissue and eschar (dark patches of dead skin) are also not present. Stage 2 injuries are a common result of an adverse microclimate (undesirable temperatures or skin surface moisture) and shear in the skin. For visual reference, see illustrations of pressure injuries from the NPUAP here.  

Stage 3 Pressure Injury: Full-thickness skin loss

Stage 3 pressure injuries involve full-thickness loss of skin, where fat tissue is visible and granulation tissue, rolled wound edges (epibole), and eschar may also be present. However, fascia, muscle, tendon, ligament, cartilage, and bone are not exposed. The depth of tissue damage may vary by anatomical location; areas with significant amounts of fat are at risk of developing deeper wounds. For visual reference, see illustrations of pressure injuries from the NPUAP here.  

Stage 4 Pressure Injury: Full-thickness skin and tissue loss

In stage 4, full-thickness skin and tissue loss has occurred, with exposed fascia, muscle, tendon, ligament, cartilage, or bone in the ulcer. Rolled wound edges (epibole) and eschar may be present. Undermining and/or tunnelling can often occur (for more information on these conditions click here). As with stage 3 injuries, the depth and extent of damage may vary by anatomical location. For visual reference, see illustrations of pressure injuries from the NPUAP here.  

There are a few other pressure injury definitions; two are important here.

Unstageable Pressure Injury: Obscured full-thickness skin and tissue loss

Unstageable pressure injuries occur when the extent of tissue damage within the ulcer cannot be ascertained because it is obscured by eschar for example. However, if the eschar  is removed, a stage 3 or stage 4 pressure injury will present. In these instances, the NPUAP advises that “stable eschar (i.e. dry, adherent, intact) on the heel or ischemic limb should not be softened or removed.”

Deep Tissue Pressure Injury: Persistent non-blanchable deep red, maroon or purple discoloration

A deep tissue pressure injury presents as (i) a localized area of persistent deep red, maroon, or purple discoloration that does not turn white when pressure is applied, or (ii) a separation revealing a dark wound bed or blood-filled blister. Pain and temperature change will often precede skin color changes. Discoloration may appear differently in darkly pigmented skin.

For more information on pressure injuries and preventive medicine, turn to MD at Home, the premier healthcare resource for primary care and geriatric medicine for homebound patients in the Chicagoland area.

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