8.1 Wound Classification

Intentional and Unintentional Wounds

Intentional and unintentional wounds are described according to their acquisition. A wound that is planned and the result of a treatment or therapy is an intentional wound. Surgical incisions, venipunctures, and lumbar punctures are examples of intentional wounds that are necessary for a specific treatment. The wounds are made in sterile conditions, and any bleeding is well-controlled, which promotes adequate healing time and reduces the risk of infection. For example, surgical incisions are made deliberately with careful techniques and in aseptic conditions, then closed immediately after the procedure.

A wound from an unexpected trauma is called an unintentional wound (e.g., a broken bone or laceration from bicycle or automobile accidents, burns, work-related injuries, or penetrating wounds from a bullet or metal fragments). These types of injury can result in multiple areas of trauma and involve tissue loss. The wounds are not acquired under sterile or aseptic conditions. Wound edges are irregular and not clean like those of intentional wounds. Bleeding is not controlled in this setting. Individuals who require medical attention may experience a delay in getting emergency help depending on location, availability to call for help or other resources, and if anyone nearby is able to help control blood loss. These conditions create the potential for a longer healing process and an increased risk of infection.

Open and Closed Wounds

A wound that breaks the skin or mucous membranes and is caused either intentionally or unintentionally is an open wound. Open wounds create an entry for microorganisms. This, combined with tissue damage and bleeding, increases the risk of a prolonged healing time and infection. Examples of open wounds include incisions, abrasions, punctures, lacerations, penetrating wounds, and avulsions. Furthermore, the term open wound is sometimes used to convey that the wound is not covered or dressed with bandages. It may even be left open to the air as part of the treatment process.

A wound that does not have a break in the skin and occurs under the skin’s surface is a closed wound. Nevertheless, there may be bleeding, tissue damage, and internal injury under the skin’s surface. Closed wounds may result from a force or blow like from a fall, being hit by an object, or a collision with a person or inanimate object. Examples of closed wounds include contusions and hematomas. Sometimes the term closed wound may relate to how wound edges are brought together. An example is when nurses say the wound is closed with sutures or staples.

Acute and Chronic Wounds

Another way to classify wounds is by acute versus chronic. A wound that occurs suddenly and progresses through expected stages of healing is called an acute wound. These wounds should be assessed based on the way they occurred and the anatomical damage (Nagle et al., 2023). Often the full extent of acute wounds is unknown until several days after an injury. Initial issues such as swelling may mask the true extent and even depth of the wound.

When patients with acute wounds present to a healthcare facility, the following wound assessments should be completed (Nagle et al., 2023):

• length of time since occurrence
• damage to underlying nerves, muscles, bones, and structures
• potential for contamination of the wound
• date of patient’s most recent tetanus shot

Nurses should expect to assist with patient care including potentially (Nagle et al., 2023):

• providing oral, topical, and/or IV antibiotics
• assisting with wound cleaning (such as irrigation)
• assisting with tissue repair (such as sutures)

In contrast to acute wounds, an chronic wound is a wound in which little to no healing occurs for at least three months (Bowers & Franco, 2020). There are a variety of ways and reasons that wounds become chronic (Table 8.3). For caregivers, these are complex to manage and may never heal completely. The goals of care for chronic wounds are to determine why the wound is not healing and identify strategies to overcome those reasons and allow the wound to heal (Nagle et al., 2023).

Pressure Injury

A localized ischemic lesion of the skin and underlying tissue caused by external pressure that impairs blood and lymph flow is called a pressure injury. The lack of blood supply, oxygen, and nutrients to the tissues results in necrosis and eventual ulceration. This ischemia also leads to inflammation and edema. Pressure injuries may also be called decubitus ulcers, bed sores, and pressure sores. This type of wound can occur in as little as one hour and may be acute or chronic. Healthy people who have full control of their limbs make changes in their position constantly. However, when someone remains in the same position for an extended period of time, an injury occurs. The portion of the skin where the patients’ weight and force are applied, is injured. Pressure injuries often arise when the soft tissues are compressed between an external surface, such as a bed or chair and a bony prominence or from friction or shearing forces that injure blood vessels and abrade the epidermis. Examples of bony prominences include the heels, sacrum, coccyx, and greater trochanter. Pressure injuries may occur in home settings, hospitals, and long-term care facilities. Pressure injuries require aggressive intervention and treatment to decrease unwarranted pain or discomfort, inhibit further tissue damage, accelerate wound healing, decrease length of stays, and decrease healthcare costs.

Moisture Exposure

Exposure to excessive moisture can cause skin maceration where the tissues are softened by the prolonged wetting or soaking. Macerated tissue makes the skin less resistant to trauma or pathogens and more susceptible to injury. Moisture from incontinence of feces or urine or gastric tube drainage promotes excoriation, the loss of the superficial layers of the skin, also known as denuded. The accumulation of excretions or secretions overhydrates the skin and makes it more alkaline. The moisture exposure irritates the skin, harbors microorganisms, and makes the skin more susceptible to breakdown and infection. In fact, any substance that is excessively applied that might overmoisten the skin can lead to skin damage. People who suffer from incontinence should be monitored for skin breakdown. Absorbent pads may be used to aid in protecting the linens from getting soiled. The patients should be cleansed as quickly as possible after each soiling; skin barriers may be used to protect intact skin (Shi et al., 2020). Examples of protective skin barriers include

• creams, emollients, and ointments;
• films and foams; and
• hydrocolloids and hydrogels.

Nutrition and Hydration

Nutrition and hydration play a major role in skin health. Cells that do not get adequate nutrition are more easily damaged. As a result of malnutrition, weight loss, muscle atrophy, and a decrease in adipose tissue can occur, resulting in the reduction of padding between the skin and bony prominences. Low protein in the blood, or hypoproteinemia leads to a negative nitrogen balance, insufficient calorie intake, edema, and electrolyte imbalances, which predispose the skin to injury. Protein is vital for wound healing as it serves multiple critical functions in the reparative process. It acts as the primary building blocks for collagen synthesis, facilitating the formation of new connective tissue essential for wound closure and tissue regeneration. Additionally, protein supports the proliferation and migration of cells involved in wound repair, such as fibroblasts and keratinocytes, enabling the formation of new tissue and the closure of the wound. Moreover, protein plays a crucial role in maintaining immune function, supporting the inflammatory response necessary for clearing debris and combating pathogens at the wound site. Protein is made up of nitrogen. Negative nitrogen balance means that the body is excreting more nitrogen than is being ingested. This will delay wound healing. Deficiencies in vitamin C may lead to frail capillaries and result in inadequate circulation, contributing to the development of pressure injuries. Edema and dehydration can also interfere with perfusion.

Mobility Status

Impaired mobility is a significant factor in pressure injury formation. People who have problems with mobility or are bedridden are unable to adjust themselves and may remain in one position for a prolonged period of time. People who have adequate mobility are able to move independently when they experience discomfort on an area of the body caused by pressure and also move freely in bed. People who are unconscious, have extreme weakness or pain, or have any other cause of decreased activity are unable to change positions and relieve the pressure even if their bodies sense the need to change position. Patients who require assistance in moving in bed or transferring are at risk of friction and shear injuries that may lead to pressure injuries if they are not properly lifted in the process.

Cognition Status

Consisting of the mental processes that take place in the brain such as thinking, language, learning, memory, perception, and attention is cognition. Patients who have an altered mental status or have decreased awareness (e.g., unconsciousness, sedation, or dementia) are at risk because they are less likely to recognize and respond to the discomfort from pressure. This means that medication or therapy that decreases a patient’s mental status can increase their risk for pressure injuries. People who are more alert are more likely to respond to increased pressure, protect their own skin integrity, and perform adequate hygiene to prevent the development of pressure injuries.

Stage I

A stage I pressure injury is characterized by localized, nonblanchable erythema of intact skin (Figure 8.2). Darker pigmented skin may not have apparent blanching, but the color of skin may differ from the adjacent skin. Purple or maroon skin discoloration may be indicative of deep-tissue pressure injuries and not a stage I pressure injury. The area may also be painful, soft or firm, or warmer or cooler than its neighboring tissues.

Figure 8.2 (a) In darkly pigmented skin, the area of concern is a different shade than the surrounding tissue. (b) In lightly pigmented skin, an area of pink and red erythema may be seen. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Stage II

Stage II pressure injuries are characterized by Partial-thickness (second-degree) skin loss involving the epidermis or dermis. The wound bed is viable, moist, red or pink, and may appear as an abrasion, shallow crater, or blister (Figure 8.3). The adipose and deeper tissues are not visible at this stage nor is slough (yellow, gray, green, tan, or brown dead tissue), eschar (hardened, black, tan, or brown necrotic tissue), or granulation tissue (delicate new reddish connective tissue or tiny blood vessels that bleed easily but provide the framework for scar tissue development).

Figure 8.3 A stage II pressure injury is a partial-thickness loss of skin with exposed dermis. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Stage III

Stage III pressure injuries are characterized by full-thickness skin loss where the adipose, granulation, and deeper tissues are visible and may have a presence of slough or eschar (Figure 8.4). The depth of this tissue damage will vary depending on its location on the body and amount of adipose tissue present. The ulcer presents as a deep crater with or without tunneling and undermining; however, fascia, tendon, ligament, muscle, cartilage, and bone are not exposed at this stage an epibole (i.e., rolled or curled-under wound edges that slow or stop the wound-healing process) may occur at this stage.

Figure 8.4 A stage III pressure injury has necrotic tissue and epibole. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Stage IV

Stage IV pressure injuries show full-thickness skin loss with extensive destruction, necrosis, and exposed or palpable fascia, tendon, ligament, muscle, cartilage, and bone (Figure 8.5). Slough and eschar are often visible along with epibole, undermining, and/or tunneling. The depth of this tissue damage will vary depending on its location on the body and the amount of adipose tissue.

Figure 8.5 A stage IV pressure injury extends to the bone, with necrotic tissue and epibole. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Deep Tissue or Unstageable Pressure Injuries

Deep-tissue pressure injuries are classified as persistent, nonblanchable areas of the skin that have maroon, deep red, or purple discoloration (Figure 8.6). The affected areas of the skin may be intact or nonintact. There is a break in the epidermis that reveals a dark wound bed or blood-filled blister. With this type of injury, changes in the color of the skin are preceded by pain and temperature changes. Skin discoloration may appear differently in individuals with darker skin. For example, a bruise that may appear bluish in a patient with light-toned skin may appear black in a patient with darker skin. Deep tissue injuries are often the results of prolonged or intense pressure and shear forces at the bone-muscle interface. This wound may resolve without tissue loss or progress rapidly to expose the magnitude of tissue injury. Deep-tissue pressure injuries should not be used to describe traumatic, neuropathic, dermatologic, or vascular skin conditions.

Pressure injuries are classified as unstageable if they have full-thickness skin or tissue loss and have excessive slough or eschar that obscures the extent of the damage. If slough or eschar is removed, a stage III or IV ulcer may be revealed. Stable eschar on the ischemic limb or heels should not be removed or softened. Stable eschar is adherent, dry, and intact without fluctuance (tense area of skin with a wave-like or boggy feeling upon palpation) and erythema.

Figure 8.6 The presence of both eschar and slough occludes the true depth of the injury and causes it to be unstageable. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)