Wound Healing: An overview

Magdalene Thangam

Senior Deputy Nursing Superintendent, Kauvery Hospital, Alwarpet, Chennai

Definition

Wound is defined as “disruption of normal structure and function”. Healing is response of the body to injury in an attempt to restore normal structure and function.

Wound Healing:

Closure of a discontinuity in tissue associated with a loss of substance (wound ) by generation of replacement tissue ( initially granulation tissue, later scar tissue).

It involves 2 distinct processes.

  • Regeneration.
  • Repair

Wound healing

  • Wound healing is the process of repair that follows injury to the skin and other soft tissues.
  • Healing is the interaction of a complex cascade of cellular events that generates resurfacing, reconstitution, and restoration of the tensile strength of injured tissue.
  • Under the most ideal circumstances, healing is a systematic process, traditionally explained in terms of

3 classic phases

  • Inflammation,
  • Proliferation,

The inflammatory phase: a clot forms and cells of inflammation debride injured tissue.

The proliferative phase: epithelialization, fibroplasia, and angiogenesis occur; additionally, granulation tissue forms and the wound begins to contract.

The maturation phase: Collagen forms tight cross-links to other collagen and with protein molecules, increasing the tensile strength of the scar.

Phase of Healing

Inflammatory Phase

  • Immediate to 2-5 days
  • B Hemostasis
  • Vasoconstriction
  • Platelet aggregation
  • Thromboplastin makes clot
  • C Inflammation
  • Vasodilation
  • Phagocytosis

Proliferative Phase

  • 2 days to 3 weeks
  • Granulation
  • Fibroblasts lay bed of collagen
  • Fills defect and produces new capillaries
  • Contraction
  • Wound edges pull together to reduce defect
  • Epithelialization
  • Crosses moist surface
  • Cell travel about 3 cm from point of origin in all directions

Remodelling (maturation) Phase

3 weeks to 2 years

New collagen forms which increases tensile strength to wounds. Scar tissue is only 80 percent as strong as original tissue

Some Factors Influencing Wound Healing

  • Age
  • Nutrition: protein and Vitamin C intake Obesity
  • decreased blood flow and increased risk for infection
  • Tissue contamination: pathogens compete with cells for oxygen and nutrition
  • Hemorrhage
  • Infection: purulent discharge
  • Dehiscence: skin and tissue separate
  • Evisceration: protrusion of visceral organs
  • Fistula: abnormal passage through two organs or to outside of body
  • Wound strength:

Factors influencing wound healing: General factors: Age, Anaemia, malnutrition.

Nutrition: deficiency of a Proteins: Causes delay in the appearance of new fibroblasts

Vitamin C deficiency: Synthesis of pro collagen is hampered Results in capillary fragility. Formation of unstable collagen which is quickly degraded by collagenolysis.

Vitamin E: Serves as membrane stabilizer & plays an important role in lysosome function.

Vitamin A deficiency: Decreases collagen synthesis and stability.

Corticosteroids: – Suppression of immune system. Medicaments: Warferin & heparin decreases formation of fibrin matrix. Depressed general resistance; infection. Systemic infection. Malignancy.

Diabetes

  • Increased susceptibility to infections due to decreased phagocytic capacity & neutrophilchemotaxis.
  • Hyperglycemia results in production of abnormal collagen.
  • Insulin is required for earliest stages of collagen formation.

Genetic disorders: Ehler Danlos syndrome. Osteogenic imperfecta. Marfan syndrome.

Coagulation disorders: Formation of poor fibrin network & abnormal platelet adhesion.

Smoking: Nicotine is potent vasoconstrictor, associated with hypercoaguability & predisposes to micro vascular occlusion.

Wound Healing Primary Intention Secondary Intention: Tissue loss

Primary Intention: Skin edges are approximated (closed) as in a surgical wound Inflammation subsides within 24 hours (redness, warmth, edema) Resurfaces within 4 to 7 days

Secondary Intention: tissue loss Burn, pressure ulcer, severe laceration Wound left open Scar tissue forms

Wound healing

  1. Initial haemorrhage: Wound is filled with blood which then clots and seals the wound against dehydration and infection.
  2. Inflammatory phase

3.Epithelial changes

  • Epidermal cells from both the margins proliferate & migrate in the form of epithelial spurs.
  • A well approximated wound is covered by a layer of epithelium in 48 hrs.
  • The migrated epidermal cells separate the underlying viable dermis from overlying necrotic material & clot, forming a scab which is cast off.

4. Organization

  • By 3rd day fibroblasts also invade the wound area.
  • By 5th day new collagen fibrils start forming.
  • In 4 weeks, the scar tissue with scanty cellular & vascular elements, a few inflammatory cells are formed.

5. Suture tracks

Stages in platelet plug formation

 

Pain Management

  • Medicate the patient prior to dressing changes as per advice
  • Provide maintenance doses of medication for those patients who have pain.
  • Adjuvant therapy may be appropriate
  • Consider non-medicinal approaches
  • Pain management is an important aspect of any plan of care.
  • Medication schedules should coincide with dressing changes.
  • Enzymatic debriders and some gels are known to be uncomfortable.
  • Surgical debridement would also cause discomfort if administered without local anesthesia.
  • Keep in mind that some wounds are more painful than others –ulcers due to arterial insufficiency.
  • Muscle relaxants or anti-inflammatories may be indicated with large, invasive wounds where underlying structures are involved.
  • Music or diversional therapy may be helpful at the time of dressing changes.

Interventions Infected Wounds

  • Diagnosis of wound infection:
  • Swab Cultures not recommended

Based on clinical signs

  • Fever
  • Increased pain
  • Friable granulation tissue
  • Foul odor)
  • Tissue culture or biopsy is not optimal for the hospice patient.
  • Treatments: Preferred agents
  • Hydrofiber (Aquacel Ag)
  • Silvadene ointment and non-sterile gauze
  • Do not use Providine Iodine
  • Hydrogen peroxide
  • Acetic Acid
  • The current thinking suggests that wound infection should be diagnosed primarily on the basis of clinical signs (fever, increased pain, friable granulation tissue, foul odor).

Nurses Role

  • Inform and consent patient
  • Identify with UHID, Follow AIDET
  • Perform hand hygiene
  • Clean surfaces to ensure you have a clean safe work surface
  • Perform hand hygiene
  • Open and prepare equipment, peel open sterile equipment and drop onto aseptic field if used (dressing pack, appropriate cleansing solution, appropriate dressings, stainless steel scissors, tweezers or suture cutters if required)
  • Perform hand hygiene, use gloves where appropriate
  • Remove dressings, discard, and perform hand hygiene
  • Clean and assess the wound (wound and peri wound should be cleaned separately if washing the patient)
  • Perform procedure ensuring all key parts and sites are protected
  • Perform hand hygiene and change gloves if required
  • Apply new dressings
  • Apply fixation if required

Perform hand hygiene 

Specific Points Affecting Wound Healing

Keep wound clean and scab free

  • Keep wound moist
  • Avoid steroid creams
  • Suturing wound splints skin
  • Wounds actually shrinks
  • The scab is a significant object in a sutures wound, so keeping the wound clean and scab free allows for quicker and smoother epithelization.
  • This can accomplished by postoperative care, including daily cleaning with hydrogen peroxide or soap and water.
  • The epithelial cells survive and move much better in a moist environment, so keeping the wound moist (without maceration) enhances this process.
  • The wound’s natural inflammatory process is important because new collagen formation, which occurs under the epithelial cells, is catalyzed by normal inflammation.
  • Epithelialization occurs only on the surface of the wound.
  • The strength of a wound is in the collagen fibers and connective tissue supporting the surface.
  • The rebuilding of these fibers takes some time, and suturing a wound splints the skin together until new connective tissue is built.
  • Wounds actually shrink.

This is a factor that must be considered in the placement of sutures and in the shape of wounds.

Kauvery Hospital