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Open Resources for Nursing (Open RN); Ernstmeyer K, Christman E, editors. Nursing Skills [Internet]. Eau Claire (WI): Chippewa Valley Technical College; 2021.
Wound healing is a complex physiological process that restores function to skin and tissue that have been injured. The healing process is affected by several external and internal factors that either promote or inhibit healing. When providing wound care to patients, nurses, in collaboration with other members of the health care team, assess and manage external and internal factors to provide an optimal healing environment. [ 1 ]
Complex wounds often require care by specialists. Certified wound care nurses assess, treat, and create care plans for patients with complex wounds, ostomies, and incontinence conditions. They act as educators and consultants to staff nurses and other healthcare professionals. This chapter will discuss wound care basics for entry-level nurses. Request a consultation by a certified wound care nurse when caring for patients with complex or nonhealing wounds.
When skin is injured, there are four phases of wound healing that take place: hemostasis, inflammatory, proliferative, and maturation. [ 1 ] See Figure 20.1 [ 2 ] for an illustration of the phases of wound healing.
Phases of Wound Healing
To illustrate the phases of wound healing, imagine that you accidentally cut your finger with a knife as you were slicing an apple. Immediately after the injury occurs, blood vessels constrict and clotting factors are activated. This is referred to as the hemostasis phase. Clotting factors form clots that stop the bleeding and act as a barrier to prevent bacterial contamination. Platelets release growth factors that alert various cells to start the repair process at the wound location. The hemostasis phase lasts up to 60 minutes, depending on the severity of the injury. [ 3 ] , [ 4 ]
After the hemostasis phase, the inflammatory phase begins. Vasodilation occurs so that white blood cells in the bloodstream can move into the wound to start cleaning the wound bed. The inflammatory process appears to the observer as edema (swelling), erythema (redness), and exudate. Exudate is fluid that oozes out of a wound, also commonly called pus. [ 5 ] , [ 6 ]
The proliferative phase begins within a few days after the injury and includes four important processes: epithelialization, angiogenesis, collagen formation, and contraction. Epithelialization refers to the development of new epidermis and granulation tissue. Granulation tissue is new connective tissue with new, fragile, thin-walled capillaries. Collagen is formed to provide strength and integrity to the wound. At the end of the proliferation phase, the wound begins to contract in size. [ 7 ] , [ 8 ]
Capillaries begin to develop within the wound 24 hours after injury during a process called angiogenesis. These capillaries bring more oxygen and nutrients to the wound for healing. When performing dressing changes, it is essential for the nurse to protect this granulation tissue and the associated new capillaries. Healthy granulation tissue appears pink due to the new capillary formation. It is also moist, painless to the touch, and may appear “bumpy.” Conversely, unhealthy granulation tissue is dark red and painful. It bleeds easily with minimal contact and may be covered by shiny white or yellow fibrous tissue referred to as biofilm that must be removed because it impedes healing. Unhealthy granulation tissue is often caused by an infection, so wound cultures should be obtained when infection is suspected. The provider can then prescribe appropriate antibiotic treatment based on the culture results. [ 9 ]
During the maturation phase, collagen continues to be created to strengthen the wound. Collagen contributes strength to the wound to prevent it from reopening. A wound typically heals within 4-5 weeks and often leaves behind a scar. The scar tissue is initially firm, red, and slightly raised from the excess collagen deposition. Over time, the scar begins to soften, flatten, and become pale in about nine months. [ 10 ]
There are three types of wound healing: primary intention, secondary intention, and tertiary intention. Healing by primary intention means that the wound is sutured, stapled, glued, or otherwise closed so the wound heals beneath the closure. This type of healing occurs with clean-edged lacerations or surgical incisions, and the closed edges are referred to as approximated. See Figure 20.2 [ 11 ] for an image of a surgical wound healing by primary intention.
Primary Intention Wound Healing
Secondary intention occurs when the edges of a wound cannot be approximated (brought together), so the wound fills in from the bottom up by the production of granulation tissue. Examples of wounds that heal by secondary intention are pressure injuries and chainsaw injuries. Wounds that heal by secondary infection are at higher risk for infection and must be protected from contamination. See Figure 20.3 [ 12 ] for an image of a wound healing by secondary intention.
Secondary Intention Wound Healing
Tertiary intention refers to a wound that has had to remain open or has been reopened, often due to severe infection. The wound is typically closed at a later date when infection has resolved. Wounds that heal by secondary and tertiary intention have delayed healing times and increased scar tissue.
Lacerations and surgical wounds are typically closed with sutures, staples, or dermabond to facilitate healing by primary intention. See Figure 20.4 [ 13 ] for an image of sutures, Figure 20.5 [ 14 ] for an image of staples, and Figure 20.6 [ 15 ] for an image of a wound closed with dermabond, a type of sterile surgical glue. Based on agency policy, the nurse may remove sutures and staples based on a provider order. See Figure 20.7 [ 16 ] for an image of a disposable staple remover. See the checklists in the subsections later in this chapter for procedures related to surgical and staple removal.
