WOUND HEALING

DEFINITION

The final phase of inflammatory process is Wound Healing. Healing takes place in two components namely

• Regeneration: Replacement of lost cells and tissue cells with same type
• Repair: Healing as a result of lost cells being replaced by connective tissue.

Regeneration: The ability of the cells to regenerate depends on the cell type. Labile cells divide constantly Eg. Skin, lymphoid organs, bone marrow and mucous membranes of GI, urinary and reproductive tracts

Stable cells retain their ability to regenerate but they do it only they are injured eg. Stable cells of liver, pancreas, kidney and bone cells

Permanent cells have left the cell cycle and do not dive eg. Cells are neurons of nervous system and skeletal and cardiac muscle will occur by repair with scar tissue.

Repair: Repair is more complex process than regeneration most injuries heal by connective tissue repair. A repair occurs by primary, secondary and tertiary intention.

Primary Intention: Healing takes place when wound margins are neatly approximated such as surgical incision or a paper cut. These processes include 3 phases.

• Initial Phase:  This lasts for 3-5 days. The edges of the incision are first aligned and sutured in place. The incision area fills with blood from cut blood vessels and blood clots form. This acts as a matrix for WBC to migrate resulting in acute inflammation. The area of injury is composed of fibrin, clots, erythrocytes, Neutrophils and other debris. Macrophages ingest and digest cellular debris fibrin fragments and RBC’s.
• Granulation: This is the second step lasts for 5 days to 3 weeks. The components of granulation tissue are fibroblast, capillary sprouts, WBC’s exudates and loose semi fluid ground substance. During granulation phase the wound is pink and vascular. Numerous red granules are present. At this point the wound is friable at risk for dehiscence and resistance to infection. The surface epithelium begins to regenerate and a thin layer of tissue is present across the wound surface. The epithelium thickens and begins to mature and wound resembles the adjacent skin.
• Maturation Phase and scar contraction: The maturation phase, during which scar contraction occurs overlaps with granulation phase. It begins 7 days after injury and continues for several months or years. Collagen fibers are further organized and the remodeling process occurs. Fibroblast disappears as the wound become stronger.

Secondary Intention: Wound that occurs from trauma, ulceration and infection has large amounts of exudates and wide irregular wound margins with tissue loss. This results in more debris cells and exudates. The debris must be cleaned away (debrided) before healing takes place. The difference of secondary intention to primary intention is that healing and granulation takes place from edges inward and from the bottom of the wound upward until the defect is filled and there is more granulation tissue and results in large scar.

Tertiary Intention: (Delayed primary Intention) Healing occurs with delayed suturing of wound in which 2 layers of granulation tissue are sutured together. This occurs when contaminated wound is left open and sutured closed after the infection is controlled. Tertiary intention results inlarger and deeper scar than primary or secondary intention.

COMPLICATIONS OF WOUND HEALING

The shape and location of the wound determine how well the wound will heal. Certain factors like malnutrition, obesity, decreased blood supply, trauma, smoking, drugs like (corticosteroids, chemotherapy) delay healing.

Complications are

• Hypertrophic scars and keloid formation: These are in appropriately large, red and raised and hard wound that extends like masses.
• Contracture: A shortening of muscle or scar tissue results from excessive fibrous tissue formation, when the wound is near the join during the process of healing
• Dehiscence: Dehiscence is separation and disruption of previous joined wound edges due to infection granulation tissue.
• Excess granulation tissue: It is also called proud flesh that protrudes above the surface of the healing wound
• Adhesions: Adhesions are bands of scar tissue between or around organs usually occurs in lungs, pleura and abdominal cavity.

Nursing care in Wound healing

• Diet therapy:
  • High fluid intake
  • Increase sources of Vitamins and proteins to promote healing
• Drug Therapy:
  • Antipyretics – Salicylates, acetaminophen, NSAIDS, corticosteroids
  • Vitamin A,B complex, C and D supplements

Assessment

• Regular Monitoring of Vital signs
• Monitor the color, size, shape and margins of the wound
• Monitor for signs of Infection like bleeding, discharges, redness, swelling & excoriations
• Obtain Wound Culture and Sensitivity to determine the presence of Micro-organisms

NURSING MANAGEMENT

R – Rest helps the body better use its nutrients and oxygen for the healing process

I – Compression and Immobilization of the inflamed area promote healing by decreasing in inflammatory process and assisting in the repair process

C- Cold and Heat is usually given at the time of initial trauma to cause vasoconstriction and decrease swelling, pain and congestion from inflammation.

E – Elevation of the injured extremity will reduce the edema at the inflammatory site and increase venous return. Elevation helps reduce pain and improve circulation.

WOUND CARE

• Red wound: Dressing with transparent film or adhesive semi-permeable dressing
• Yellow wound: It is a non viable necrotic tissue with bacterial growth (calcium alginate, foam, hydrogel) is used to draw the excess drainage from the wound surface and clean the wound
• Black wound: It is covered with thick, dry, black necrotic tissue called eschar. The debridement methods used are
• Surgical debridement: Large amounts of Non viable tissues are removed surgically
• Mechanical debridement: It is wet to dry dressing in which open mesh gauze is moistened with normal antibiotics like betadine, sodium hydrochloride, hydrogen peroxide and chlorhexidine is used to clean granulating wound. Wound irrigation is also a method of mechanical debridement.
• Autolytic debridement: Semi occlusive or occlusive dressings may be used to promote softening of dry eschar by autolysis
• Enzymatic debridement: Drugs like collagenase and gludase gel are topically applied on the necrotic tissue and covered with moist dressing such as saline moistened gauze.