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Classification of pressure injuries

A pressure ulcer is an area of reddened skin that progresses to a breakdown of skin and underlying tissue to form an erosion or ulcer and is due to persistent pressure on the affected area. A pressure ulcer is also known as a bedsore, decubitus ulcer, pressure wound, and pressure ulceration.


The most common sites for developing pressure injuries are where there is relatively little tissue covering bony prominences like over the sacrum, tuber ischiadicum, the greater trochanteric regions, heels, and lateral malleoli.


There are several classification systems for pressure injuries, but the classification developed by the European Pressure Advisory Panel (EPUAP) is internationally acknowledged and the system that is probably most used worldwide.  This is an easy-to-use classification system, and the categories depend on the depth of the skin damage.


Stage 0:  Temporary redness in otherwise intact skin.  There may be some pain involved. When you put slight pressure on the skin ( with your finger or a special clear plexiglass tool), This phenomenon is called blanching. Blanching is a good sign!  It means that the skin damage has not advanced too much.  Dette kaller man blanching (uttales "blansjing") og betyr bleking på engelsk. Blanching er et godt tegn! 


Stage 1:  Persistent redness in otherwise intact skin.  To be exact, Stage 1 is defined as redness that lasts for an hour or longer. In stage 1 pressure injuries, we don't see blanching!  When we put pressure on the reddish skin, it does not become paler - i.e., we, therefore, call this stage "non-blanching."  This is an indicator of more severe skin damage. In patients with darker skin, it can be quite difficult to detect redness of the skin.  Here it is helpful to feel for increased temperature, localized edema, or an increased hardness of the tissue ( indurated tissue).  Stage 1 skin injuries are an indicator of deeper skin damage and secondary inflammation.  If the area is off-loaded immediately, the damage can be reversible.  If it is not offloaded, it will develop into a stage 2 injury or even deeper. 


Stage 2: Here, the skin is no longer intact, but the damage is still quite superficial.  The skin is usually red and painful. Often we see blisters or superficial skin abrasions.  Stage 2 ulcers typically heal well with immediate off-loading. 


Stage 3: Pressure ulcers that go as deep as the subcutaneous layers but not through the fascia.  That is- the fascia may be visible but is intact. Often stage 3 ulcers are less painful than stage 1 and 2 skin injuries. The skin edges are often quite sensitive to pain, while the deeper part of the erosions may be quite pain-free. However, stage 3 ulcers take a long time to heal and need continuous off-loading, not seldom requiring considerable resources to heal. Often there is some necrosis that may require surgical debridement. 


Stage 4: Very deep pressure ulcers that go down to muscles or even bone through the fascia. There is a deep crater, often with undermined skin edges or fistulas. There is usually a significant amount of exudate, which can be problematic and cause moisture-associated skin breakdown, which increases the ulcer even more.  Like stage 3 ulcers, the skin edges are usually painful, while the bottom of the ulcers generally has little pain.  If there is undermining of the skin, this is a poor prognostic factor- expect the ulcer to take at least 2-3 times slower healing rate than when there is little or no undermining. som går ned til muskel og eventuelt benvev. Often there is some necrosis that may require surgical debridement.  If there is exposed bone, you have to have a high level of suspicion regarding osteomyelitis.  Do not underestimate how quickly osteomyelitis can develop in these wounds. If you have an otherwise clean wound and are offloading the ulcer for weeks on end without progress, suspect osteomyelitis to be the reason for non-healing. 


IUnstageable ulcer:  If there is much necrosis, it may be impossible to see how deep the ulcer is before it has been debrided. The ulcer is often a stage 3 or 4 when you have an unstageable ulcer, to begin with. Never underestimate the depth of an unstageable ulcer! It is usually worse than you expected. 

Figure 1 Stage 0 skin injury.  Here a little plexiglass plate was used ( actually a keyring holder where you can insert a photo into the plexiglass frame) to demonstrate blanching- if you look closely, you see paleness in the middle under the plexiglass. You can also use your index finger to press on the skin  - do not press hard - a slight pressure is enough. 

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Figure 2 Stage 1 pressure injury.  In this case, the skin was found to be non-blanching, but the skin is still intact otherwise. 

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Figure 3 Stage 2 pressure injury on the lower back. The skin is broken, but the damage is still superficial.

Figure 4   Here, we see a mixture of different stages.  On the left side of the buttock area  ( towards the bottom of the picture), we see a stage 3 ulceration going down into subcutaneous layers. On the right side of the buttocks ( upper part of the picture), we see necrotic skin - this may be superficial, but we simply cannot tell  - so this is unstageable until it has been debrided. We expect this to be at least a stage 3 ulcer lying beneath that necrotic skin. 

Figure 5 Stage 3 pressure ulcer in the sacral area.  The reddish area is granulation tissue in the wound bed. The fascia is still intact.  From the picture alone, we see that there must be some undermining, and we see some moisture-associated skin damage on the wound edges ( maceration).

Figure 6 Stage 4 pressure ulcer over the buttock ( tuber ischiadica). The ulcer has gone through the fascia and muscle and is only some millimeters away from the bone. There is some necrotic slough on the bottom left of the ulcer and clearly some undermining of the skin edges. 

Figure 7 Non-stageable pressure ulcer on the lateral edge of the foot. There are various phases of necrotic tissue to be seen.  This pressure injury is non-stageable until we have done a wound debridement. At this part of the foot it is quite a short distance from the skin to the bone - so this sort of injury very quickly becomes a stage 4 pressure ulcer. 

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Figure 8 Another unstageable ulcer over the right buttock.  We have to debride this before we can stage it. Note- as long as the patient doesn't have any systemic signs of infection, there is no need for antibiotics here.  On the left buttock is a stage 2 ulcer. 

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