Learning Objectives
By the end of this section, you will be able to:
- Differentiate types of common wounds
- Distinguish between partial-thickness and full-thickness wounds
- Identify types of wound closure
- Describe barriers to wound healing
The wound-healing cascade, or process, is a complex overlapping system of biochemical and physiological pathways that secrete inflammatory cells and cytokines on the way to healing. Although the process contains the same four phases for all wounds, different types of wounds may require different approaches by the care team. This module will introduce the reader to the various types of wounds, as well as various methods for wound closure and barriers that wounds may encounter while healing.
Types of Wounds
Clinicians, including nurses, care for many types of wounds; it is important to understand the different types of wounds and their identifying characteristics, as each type has a specific treatment. Some therapies may be appropriate for one type of wound and detrimental to another. Understanding the wound’s etiology helps foster treatment as well. For example, an acute wound progresses through the phases of healing without complication. In contrast, a chronic wound is a wound that fails to progress through the phases of wound healing in a timely fashion.
Open wounds are another important category in nursing practice. They involve an external or internal break in the tissue. Examples of open wounds include abrasions, lacerations, punctures, avulsions, skin tears, and incisions (Table 28.3).
| Open Wound Type | Description |
|---|---|
| Abrasion | Removal of the skin from rubbing against a hard surface |
| Laceration | Torn or jagged wound caused by blunt force trauma |
| Puncture | Wound caused by a sharp, pointed object that penetrates the skin |
| Avulsion | Partial or complete tearing away of the skin and underlying tissue; also known as degloving |
| Skin tears | Wound caused by friction or shear, causing separation of skin layers |
| Incision | A surgical wound made to facilitate a procedure |
Other common wound types that a nurse may encounter include venous ulcers, arterial ulcers, diabetic foot ulcers, and pressure injuries.
Partial-Thickness vs. Full-Thickness Wounds
A partial-thickness wound is a superficial injury that involves the epidermis, dermis, or both. Partial-thickness wounds can present as a crater, abrasion, or blister. Although the topic of pressure injuries will be discussed in 28.3 Pressure Injury, it is important to understand that Stage 1 and 2 pressure injuries are considered partial-thickness wounds. In contrast, a full-thickness wound extends through all skin layers, potentially extending to the muscle fascia or bone. Stage 3, Stage 4, unstageable, and deep tissue injuries are examples of full-thickness injuries.
Types of Wound Closure
Wound closure from healing occurs through three methods: primary, secondary, or tertiary intention. Regardless of the closure method, a wound will progress and heal by moving through the four phases of wound healing.
Primary Intention
Primary wound closure, also referred to as healing by primary intention, is the fastest type of wound closure. Primary intention refers to the healing of a wound or injury with clean edges that can be approximated, or brought close together. The approximated edges allow wound contraction, proliferation, and epithelization to occur quickly, resulting in limited scarring. Surgical wounds closed by sutures, staples, or surgical glue typically heal by primary intention.
Secondary Intention
Healing by secondary intention occurs with wounds whose edges cannot be approximated or brought together, so the wound heals from the “bottom up” with granulation tissue. Secondary intention occurs when the wound cannot be surgically closed. This is often seen in wounds such as venous leg ulcers, pressure injuries, and skin tears. Wounds that heal by secondary intention are at a higher risk of infection and scar formation. Medical devices such as negative pressure wound therapy (NPWT) may assist with healing wounds from the bottom up. Therapies such as NPWT will be addressed later in the chapter.
Tertiary Intention
The term tertiary intention, also referred to as delayed primary intention, involves a plan to allow the wound to remain open. Reasons for the delayed closure could include waiting for the infection to resolve or preparing the wound for primary closure via a graft, flap, or skin substitute.
Cultural Context
Religious Considerations
Cultural competency is a cornerstone of patient-centered health care. Certain religious doctrines or cultures may define the appropriate consumption or use of certain animals and forbid the use of others. Some wound care products contain ingredients that are animal-derived. For example, certain skin substitutes are derived from pig placentas. However, religions such as Islam and Judaism, as well as some Christian denominations, forbid the use of pork products. If providing wound care to a Muslim or Jewish patient, the nurse would likely need to inform the patient about or use alternatives to pig-derived products. Furthermore, knowledge of animal-derived ingredients can help foster deeper conversations with patients about spiritual and cultural needs.
Barriers to Wound Healing
There are a variety of barriers to wound healing, such as those due to physical, physiological, local, and systemic origins. Several main risk factors that impede wound healing include age, immune status, perfusion, smoking, comorbidities, and immune and nutritional deficiencies. Comorbidities such as diabetes are directly linked to delayed wound healing. Extrinsic factors contributing to delayed wound healing include support surfaces, friction, and shearing forces.
Chronic wounds are wounds that fail to progress through the wound-healing cascade in a timely manner. According to the U.S. Centers for Medicare and Medicaid Services (CMS), if a wound has not closed or progressed within thirty days, it is considered chronic (Baranoski & Ayello, 2020). For a wound to heal or progress through the healing cascade, the wound bed must be prepared in a manner known as wound bed preparation (WBP). WBP begins with assessing the patient and their environment and determining their knowledge of their wound and health literacy. It is important for the nurse to assess the whole patient, not just the wound. Wound bed preparation is a nonsequential process of assessment, intervention, and evaluation that can be achieved through the acronym TIME, which stands for tissue, infection/inflammation, moisture, edges. The TIME principles of wound bed preparation guide the clinician in addressing the local barriers to healing and aligned interventions.
Link to Learning
The TIME principles focus on wound assessment and allow the clinician to assess the patient and wound in a systematic fashion. This article explains the evolution of TIME and its holistic nature, as well as how to implement TIME principles in practice.
Tissue Degradation
The presence of necrotic or devitalized tissue is a critical barrier to wound progression and healing; if the keratinocytes cannot migrate or granulation cannot fill a wound due to “roadblocks” of necrotic tissue, a wound will not heal. The necrotic tissue, or avascular debris, can appear as eschar, slough, or biofilm—a layer of microscopic bacteria or other microorganisms, usually combined with a polysaccharide matrix, which adheres to a wound surface. Necrotic or nonviable tissue requires debridement for removal. The purpose of wound bed debridement is to stimulate healing through the removal of necrotic tissue, elimination of dead space harboring bacteria, and drainage of pus; it also helps to reduce pressure, allowing for an inspection of underlying tissue, and optimize the site for topical preparations. The choice of the most appropriate debridement technique involves patient factors, wound appearance, environmental factors, and practitioner competence.
Infection and the Inflammatory Process
Many chronic wounds are identified as hosting bacteria or fungi. This is because the wound bed has typically been open for an extended period and becomes further exposed to environmental factors during each dressing change. Chronic wounds also often have poor perfusion to the wound bed, creating a favorable environment for organisms. Most chronic wounds are accompanied by biofilm development. A biofilm can perpetuate the inflammatory phase, inhibiting chronic wounds from healing (Ozgok & Regan, 2023). The best way to interrupt the biofilm is debridement. If infection is evident, the provider may add antibiotics to the wound care orders.
Moisture Imbalance
Traditionally, people thought that drying out a wound sped healing. However, studies have shown, and best practices support, that a wound requires an amount of moisture to help facilitate the migration of keratinocytes to accelerate epithelialization (Nuutila & Eriksson, 2021). Achieving appropriate moisture balance involves the creation and maintenance of a warm, moist wound bed and the stimulation of components in the moisture that have a positive impact on wound healing, such as growth factors. An appropriate amount of moisture is needed for the optimal effects of growth factors and cytokines and for the growth of proliferating cells, such as keratinocytes, endothelial cells, and fibroblasts. Excessive moisture may lead to the maceration of wound edges, whereas inadequate moisture may inhibit cellular activities and promote eschar formation.
To address the excess or deficiency of moisture, depending on the institution’s policy, the nurse or provider should select the appropriate wound care dressing or treatment. To add moisture, a hydrogel dressing or saline-moistened gauze is applied to the wound bed. Common dressings used to manage moisture include foam dressings, alginate dressings, gauze, or negative pressure wound therapy (NPWT).
Impact on the Edge of a Wound
One of the key indicators of a healing wound is progression of the edge of a wound in terms of epidermal cell and keratinocyte migration and wound contraction. Once tissue viability, infection, inflammation, and moisture have been addressed, wound edge advancement should indicate healing progression. Wound edge management is an important part of the healing process. Wound edges may become callused or rolled, or they may develop maceration, undermining, or tunneling. All these conditions require intervention so the wound may progress through closure.
The wound edge tells a story that the nurse must understand. If the wound edge has a callus, such as with a diabetic foot ulcer, the callus needs to be removed to allow the edge to epithelialize. Typically, this is achieved through sharp debridement. When wound edges become rolled instead of advancing across the wound surface, the condition is called epibole; it also requires debridement. The erosion of the tissue under edges of a wound is called undermining, whereas tunneling is the formation of a sinus tract, which can harbor bacteria. Undermining and tunneling require wound packing to advance toward healing.
Physiological Components of Wound Healing
The many processes involved with wound healing create a large metabolic demand that is met with oxygen and glucose transported to the wound site by newly formed endothelial vessels. Factors leading to vasoconstriction limit this blood supply and thus prevent proper wound healing. Causes of vasoconstriction include pain, cold, fear, nicotine, beta antagonists, and hypovolemia. Health-care providers attending to patients with healing wounds should be aware of these factors and control for them when possible. Patients should be screened for and counseled about the use of substances and medications that might impair or delay wound healing. Furthermore, comorbidities or underlying health or medical conditions can impact wound healing. Common conditions include diabetes, peripheral vascular disease (PVD), anemia, stress, peripheral neuropathy, and arterial disease. Patient education should include how comorbid conditions and lifestyle choices impact or influence the wound-healing process.
Nutritional Status
Nutritional status affects wound healing. The wound-healing process makes greater energy and nutrient demands on the body. Nutritional deficiencies, including low levels of vitamin C, zinc, iron, and vitamin A, have been linked to an increased risk of infection and decreased wound tensile strength (Ozgok & Regan, 2023).
Wound Complications
In addition to delayed wound healing, other complications can occur. Common wound complications include hematoma development, infection, and dehiscence.
A hematoma is an area of blood that collects outside of large blood vessels. A hematoma occurs when small veins and capillaries under the skin break. The development of a hematoma at a surgical site can lead to infection and incisional dehiscence. Upon inspection, hematomas related to wound care can appear as blood-filled blisters that are purple or deep red in color.
The separation of the edges of a surgical wound is called dehiscence (Figure 28.3). A dehisced wound can appear fully open, with visible tissue underneath, or with partial separation. The most common areas for dehiscence include abdominal surgeries and vascular surgical sites. Regardless of the incision site, patients with a history of stroke, chronic obstructive pulmonary disease (COPD), diabetes, or cancer have higher rates of dehiscence. Dehiscence is always a risk in a surgical wound, and the risk increases if the patient has obesity, is a smoker, or has other comorbidities, such as diabetes, that impact wound healing. Wound dehiscence can occur suddenly. Some signs of impending dehiscence include redness around wound margins and increasing drainage from the incision. The wound will also likely become increasingly painful.
To prevent the dehiscence of a wound, surgical patients must carefully follow all postoperative instructions, including restricting activities, avoiding heavy lifting, and protecting the site from external damage.