8.1: Wound Classification
By the end of this section, you will be able to:
- Identify the different classifications of wounds
- Recognize the risk factors for pressure injury development
- Describe the staging process for pressure injuries
A wound is defined as an injury that causes a disruption of normal skin or tissue integrity. Wounds can be typed as an incision , contusion , abrasion , laceration , puncture , penetration , avulsion , burn , and ulcer (Table 8.1). In order to effectively manage wounds, nurses must first recognize the various wound classifications, as well as identify individuals at risk of pressure injury development, and describe the technique for staging pressure injuries.
| Wound Type | Description |
|---|---|
| Abrasion | An area of skin or tissue damaged by scraping |
| Avulsion | A forcible tearing off of skin or another part of the body |
| Burn | Injury to the skin caused by thermal, electrical, chemical, or electromagnetic energy |
| Contusion | A region of injured tissue or skin in which blood capillaries have been ruptured (bruise) |
| Incision | A surgical cut made in skin or flesh |
| Laceration | A deep cut or tear in the skin or flesh or underlying tissue |
| Penetration | A wound caused by an object that pierces the skin and lacerates or damages adjacent tissue |
| Puncture | A wound made by a pointed object |
| Ulcer | An open sore caused by poor blood flow |
Different Types of Wound Classification
Wounds are classified in several ways and include intentional or un intentional wound s, open or closed wound s, acute or chronic wound s, pressure injuries, and friction and shear . Wounds also may be described according to how they were acquired, how long the wound has been present, or how deeply the wound affects the skin or tissues (Table 8.2).
| Classification | Description | Example |
|---|---|---|
| Intentional wounds |
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| Unintentional wounds |
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| Open wounds |
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| Closed wounds |
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| Acute wounds |
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| Chronic wounds |
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| Pressure injuries |
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| Friction injuries |
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| Shear injuries |
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Intentional and Unintentional Wounds
Intentional and un intentional wound s 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).
| Cause | Explanation |
|---|---|
| Arterial insufficiency (such as scleroderma or Reynaud disease) | Insufficient arterial blood flow to the extremities impacts the transportation of oxygen and even antibiotics to diseased tissues. |
| Venous insufficiency | Insufficient return of blood from the extremities causes increased pressure and fluid in intravascular spaces, decreasing the body’s ability to heal effectively. |
| Infection | Infections in tissues and bones (cellulitis and osteomyelitis, respectively) prevent the healing process. Expect to culture for biological, viral, and fungal agents. |
| Pressure | Constant or frequent pressure against healing tissues impacts the ability to heal and/or tears healing tissues back open. |
| Radiation therapy | Radiation may cause occlusion or damage to blood vessels, impacting healing of localized tissues. |
| Systemic diseases | Diseases such as diabetes and immunodeficiencies may impact the body’s ability to heal naturally. |
| Nutrition | Protein malnutrition and elevated glucose levels can impact healing. |
| Age and hormones | While older age may lengthen the time it takes for an acute wound to heal, it does not cause chronic wounds. However, differences in androgens and estrogen may impact healing. |
| Medications | Several medications, including hydroxyurea, chemotherapeutic agents, and steroids, can slow healing. |
| Genetic issues | There is a genetic predisposition to issues such as keloid scarring and other skin conditions that may negatively impact wound healing. |
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.
Friction and Shear
Friction and shear are mechanical forces that tear and injure blood vessels and can contribute to the development of pressure injuries. When two surfaces rub together, which generates heat and can remove the top layer of the skin, damage superficial blood vessels, and may look like an abrasion is called friction . Friction injuries may occur when a patient attempts to push themselves up in bed using their heels, arms, or hands. This can also happen when patients are pulled up in bed by a draw sheet or transferred to a stretcher using a transfer or draw sheet.
When one tissue layer slides over the other a shear results. The shearing force separates the skin from its underlying tissues. Blood vessels stretch and bend or tear, causing injury, thrombosis, and impaired circulation to the tissue cells. Shear injuries may occur when patients are pulled when being moved up in bed or transferred from bed to stretcher or chair. Shear injuries may also occur if a patient slides down when sitting in a chair or their torso slides down when sitting in bed and the head of the bed is elevated.
Part of the aging process occurs when changes in skin collagen makes skin less elastic. The subcutaneous and dermal tissues are thinner, and the patient often has reduced sensations of pressure and pain. This makes older adults more susceptible to friction and shear injuries. Careful considerations for the older adult include checking skin frequently to monitor for breakdown or tears, ensuring bedding and linens are dry and wrinkle free, padding bony prominences, and ensuring proper lifting technique when moving patients in bed or transferring out of bed.
Risks for Pressure Injury Development
Pressure injuries may result from pressure, friction, and shearing forces but may also be caused by other factors. The risk factors for pressure injury development include moisture exposure, nutrition and hydration, mobility, and level of cognition . Other factors that may contribute to pressure injuries include the following:
- advanced age
- poor skin hygiene
- loss of sensation
- fractures
- immunosuppression
- diabetes
- history of corticosteroid use
- multiple organ dysfunction
- history of previous pressure injuries
- increased body temperature
- having a higher weight
- having a lower weight
- terminal illnesses
- end-of-life processes
- microvascular dysfunction
See the competency checklist for Preventing Pressure Injury. You can find the checklists on the Student resources tab of your book page on openstax.org.
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.
Staging Pressure Injuries
Depending on the extent of damage, pressure injuries are assessed and classified as stages I through IV or as deep tissue or unstageable. Stage one is the least severe of the stages. It is essential for nurses to adequately stage pressure injuries to implement appropriate interventions and assess for improvement or worsening damage.
Blanching is part of the assessment process and can aid in identifying those at risk of pressure injury development. Normal blanching is temporary whitening or lightening of the skin around the wound site upon applying pressure. When the pressure is relieved, normal blood flow should return promptly to the area and return to the skin’s normal color.
Prolonged pressure to an area makes it more difficult for adequate blood flow to return, thus resulting in pressure injuries. Patients who have been sitting or lying in a prolonged (e.g., two hours or more) position who are then repositioned may take sixty to ninety minutes for hyperemia (reddening of the skin) and warmth of the skin to resolve.
The Spinal Cord Injury Research Evidence website has offers an excellent guide for the identification of pressure injuries, including pictures and appropriate terminology to use with all patients experiencing 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.
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).
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.
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.
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 .