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UNIT 4 Supporting Physiological Function
Table 32-2 ➤ Chronic Wounds TYPE ETIOLOGY
CHARACTERISTICS
Pressure injury
Caused by pressure, shear, and friction, resulting in tissue ischemia and injury Caused by inadequate circulation of oxygenated blood to the tissue, which leads to tissue ischemia and damage
■ Appearance depends on the stage or tissue layers involved. ■ Pressure injuries tend to be located over bony prominences or related medical device (National Pressure Injury Advisory Panel [NPIAP], 2019). ■ Can cause serious tissue damage ■ Commonly found over the lower leg, especially the ankles, toes, side of the foot, and shin ■ Ulcer appears “punched out,” small and round with smooth borders. ■ Wound base is usually pale, with or without necrotic tissue. ■ Surrounding skin is shiny, thin, and dry and is cool to the touch. ■ Loss of hair in the surrounding area ■ Delayed capillary refill time in the area ■ Very painful, especially at night and with increased activity ■ Usually located around the inner ankle or in the lower part of the calf ■ Surrounding skin is reddened or brown and edematous. ■ Usually shallow, with irregular wound margins ■ Wound bed appears “ruddy” or “beefy” red and granular. ■ Drainage may be moderate to heavy, depending on amount of edema. ■ Pain usually occurs with leig dependence and dressing changes. ■ Often painless; often with drainage, swelling, redness, and ulceration ■ Occurs mainly on the plantar surfaces and toes (balls of the foot or underside of the toes) ■ Highly susceptible to wound infection because of the poor sensation, circulation, and immune protection
Arterial ulcers
Venous stasis ulcers
Caused by incompetent venous valves, deep vein obstruction, or inadequate calf muscle function, resulting in venous pooling, edema, and impaired circulation of the skin Caused by narrowing of the arteries, which leads to reduced oxygenation to the feet, resulting in delayed wound healing and tissue necrosis
Diabetic foot ulcer
of poor circulation are more difficult to heal (e.g., feet for those with diabetes or congestive heart failure). ■ Superficial wounds involve only the epidermal layer of the skin. The injury is usually the result of friction, shearing, or burning. ■ Partial-thickness wounds extend through the epider- mis but not through the dermis. ■ Full-thickness wounds extend into the subcutane- ous tissue and beyond. The descriptor penetrating is sometimes added to indicate that the wound involves internal organs. Knowledge Check 32-3 ■ Explain the difference between an acute and a chronic wound. ■ Describe the wound categorization system based on the level of contamination. ■ How does wound depth affect healing? Wound Healing Process All wounds heal through a physiological process in which epithelial, endothelial, and inflammatory cells,
platelets, and fibroblasts (cells in connective tissue that produce fibrin) migrate into the wound to bring about tissue repair and regeneration. The process is essentially the same regardless of the type of injury or the type of tissues involved. Types of Healing Wounds may heal by regeneration or by primary, sec- ondary, or tertiary intention. ■ Regenerative/Epithelial Healing. This takes place when a wound affects only the epidermis and dermis. No scar forms, and the new (regenerated) epithelial and dermal cells form new skin that cannot be distin- guished from the intact skin. Partial-thickness wounds heal by regeneration. ■ Primary (First) Intention Healing. This occurs when a wound involves minimal or no tissue loss and has edges that are well approximated (closed) (Fig. 32-4A). Little scarring is expected. A clean surgical incision heals by this method. Even so, a scar is only 80% as strong as the original tissue (Mercanetti, 2021).
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