Wound Healing

Three types of wound healing.

(1)        Primary intention (primary union)

•     Wounds that are closed surgically
•     Little tissue loss
•     Skin edges are close together and minimal scarring
•    Healing begins during the inflammatory phase

(2)        Secondary intention (granulation)

• Healing occurs when skin edges are not close together (approximated) or when pus has formed
• If wound is producing or containing pus (purulent) a drainage system is established or the wound is packed with gauze
• Slowly the necrotized tissue decomposes and escapes
• The cavity begins to fill with soft, pink, fleshy projections consisting of capillaries surrounded by fibrous collagen (granulation tissue)
• The amount of granulation tissue required depends on the size of the wound
• Scarring is greater in a large wound

(3)        Tertiary (third) intention

•  Delayed primary closer
•  Two layers of granulation tissue are sutured together
•  Occurs when:   Contaminated wound is left open and sutured closed after the infection is controlled  Delayed suturing of a wound.   Primary wound becomes infected, is opened, is allowed to granulate, and is then sutured.
• Results in a larger and deeper scar than primary or secondary intention

Factors promoting wound healing

(1)        Adequate oxygenation

(2)        Adequate rest or local immobilization

(3)        Sufficient blood supply

(4)        Proper nutrition

(a)        Nutrients are needed for wound repair and prevention of infection

(b)        Adequate wound healing is dependent upon the availability of essential nutrients

Factors that impair wound healing

(1)        Age - causes slower regeneration of tissue

      Physiological Effects

(1)        Alters all phases of wound healing

(2)        Vascular changes impair circulation to wound site

(3)        Reduced liver function alters synthesis of clotting factors

(4)        Formation of antibodies and lymphocytes is reduced

(5)        Collagen tissue is less pliable

(6)        Scar tissue is less elastic

       Interventions

(1)        Instruct patient on safety precautions to avoid injuries

(2)        Be prepared to provide wound care for longer period

(3)        Teach home caregivers wound care techniques

(2)     Malnutrition

       Physiological Effects

(1)        All phases of wound healing are impaired

(2)        Stress from burns or severe trauma increases nutritional requirements

      Interventions -  Provide balanced diet rich in protein, carbohydrates, lipids, vitamins A and C, and minerals

(3)       Obesity

       Physiological Effects -  Fatty tissue lacks adequate blood supply to resist bacterial infection and deliver nutrients and cellular elements

       Interventions - Observe obese patient for signs of wound infection, dehiscence, and evisceration

(4)       Impaired oxygenation

        Physiological Effects

(1)        Low arterial oxygen tension alters synthesis of collagen and formation of epithelial cells

(2)        If local circulating blood flow is poor, tissues fail to receive needed oxygen

(3)        Decreased hemoglobin (anemia) reduces arterial oxygen levels in capillaries and interferes with tissue repair

        Interventions

(1)        Diet adequate in iron

(2)        Monitor patients’ hemotocrit and hemoglobin levels

(5)        Smoking

        Physiological Effects

(1)        Reduces the amount of functional hemoglobin in blood, thus decreasing tissue oxygenation

(2)        May increase platelet aggregation and cause hypercoagulability

(3)        Interferes with normal cellular mechanisms that promote release of oxygen to tissue

        Interventions -  Discourage patient from smoking by explaining its effects on wound healing

 (6)       Presence of infection

 (7)       Drugs

      Physiological Effects

(1)        Steroids reduce inflammatory response

(2)        Anti-inflammatory drugs suppress protein synthesis, wound contraction, epithelialization, and inflammation

(3)        Prolonged antibiotic use may increase risk of superinfection

(4)        Chemotherapeutic drugs can depress bone marrow function, number of leukocytes, and inflammatory response

        Interventions  - Carefully observe patient; signs of inflammation may not be obvious

(8)        Diabetes mellitus

       Physiological Effects

(1)        Causes small blood vessel disease that impairs tissue perfusion

(2)        Causes hemoglobin to have greater affinity for oxygen, so it fails to release oxygen to tissues

(3)        Alters ability of leukocytes to perform phagocytosis and also supports overgrowth of fungal and yeast infection

        Interventions

(1)        Instruct patient to take preventive measures to avoid cuts or breaks in skin

(2)        Provide preventive foot care

(3)        Control blood sugar to reduce the physiological changes associated with diabetes