Pressure-induced skin and soft tissue injury: Clinical sciences

Pressure-induced skin and soft tissue injury, sometimes called pressure ulcer, or bed sores, refers to damage to the skin and underlying soft tissues caused by prolonged pressure. Pressure injuries most commonly develop over bony prominences, such as the sacrum, greater trochanter, lateral and medial malleoli, calcaneus, scapula, and occiput. Pressure decreases blood flow to the affected skin and soft tissues, leading to hypoxia, ischemia, and necrosis. Based on the depth of the tissue involved, pressure injuries can be subdivided into four main stages. In stage one, there’s intact skin with non-blanchable erythema; in stage two, there’s partial thickness loss of dermis; while in stage three, there’s a full thickness skin loss. Finally, stage four is associated with full thickness skin loss and exposure of underlying muscles, tendons, or even bones.

The first step in evaluating a patient with signs and symptoms of pressure injury is to obtain a focused history and physical examination. Patients often have a history of risk factors such as immobility, like using a wheelchair or being bed bound, in fact they can start developing pressure injuries after just 2 hours of immobility! Other risk factors include malnutrition; neurological diseases like stroke and neuropathy; diabetes; or perfusion disorders, like heart failure and peripheral vascular disease. Additionally, they typically have pain in the affected area, but keep in mind that individuals with sensory neuropathy, diabetes, or altered mental status may not report pain.

Now, during the physical examination, you’ll need to assess the wound bed and depth, which are the most important factors as they determine the grade of the injury. The wound bed is the base of the wound, while the depth is how deep the wound bed is from the skin surface. While examining the wound, don’t forget to note the type and quality of tissue seen at the wound bed. You may find exudate, or a wet, fibrinous biofilm caused by cell necrosis, covering the wound bed. Next, check the skin color and look for edema surrounding the wound, which can help you identify the presence of infection. For example, erythema and mild edema can indicate cellulitis; while “bogginess” or gray discoloration with moderate to severe edema might suggest infectious tissue necrosis. Gas producing pathogens can cause crepitus, or a crackling sound on skin palpation.

Finally, there might be signs of wound healing, such as granulation tissue and epithelialization. The presence of “beefy red” granulation tissue indicates adequate blood flow fundamental to the healing process; while epithelialization occurs later, as the wound bed creates a healthy protective layer that functions like the epithelium of the skin.

Some high yield facts to keep in mind! Because pressure injuries are open to the atmosphere, the wound is never sterile and the risk of infection is high. If you see any signs of infection or necrosis, make sure to treat the infection and remove any necrotic tissue before starting treatment. The presence of infection and necrosis will prevent proper wound healing, rendering other additional methods of treatment ineffective.

Alright, during the initial evaluation, you should look out for any signs of critical infections including sepsis, limb-threatening ischemia, and rapidly progressing skin and wound changes. If you suspect any of these, immediately establish IV access, draw blood cultures, start empiric IV antibiotics, and call for an emergent surgery evaluation. The surgical team will usually perform wound debridement, but amputation might be required in severe cases.