Chapter 21: Wound Healing Flashcards
What are the skin layers?
- Pink and Purple, Top Layer = Epidermis
- Light Pink, Middle Layer = Dermis
- Yellow, Bottom Layer = SubcuQ fat
Which skin layer provides critical components of the immune response for theh complex processes of wound healing?
DERMIS
Define partial thickness versus full thickness wounds.
- Partial = shallow wounds involving full or partial epidermal loss and partial loss of the dermal layer
- Full = Total loss of the both epidermal and dermal layers, extending to at least the subcutaneous tissue layer and possibly as deep as the fascia, muscle layer, and the bone.
Define chronic wounds
Wounds that have not healed within 12 weeks of the initial injury
What are the 3 phases of healing?
- Inflammatory Phase
- Proliferative Phase
- Maturation Phase
Explain the inflammatory phase.
How long does it last?
- Beings immediately following an acute injury to the tissue and is accompanied by the classic signs of tissue damage, including rubor (redness), heat, swelling, and pain.
- Fibrin clot forms and forms protective barrier
- Inflammatory mediators are released that attract neutrophils and monocytes to the wound.
- Neutrophils arrive w/in 6 to 12 hours after initial injury
- Leukocytes and monocytes arrive, over the next 24 hours and over the next 3 to 7 days
- During this phase, the foundation is set with granulation tissue, and the removal of cellular debris and other foreign materials prepares the site of healing.
- The need for energy, protein and micronutrients (vitamins C, E, and K, iron, selenium, and copper) increases
The prescence of which vitamin in the extracellular environment protects the neutrophils, fibroblasts, and collagen, thereby allowing the wound healing process to transition from the inflammatory to the proliferative phase.
Vitamin C
- It also helps maintain homeostasis at the wound site by promoting the inflammatory phase whil participating in the regulation of ROS production and oxidative damage.
Explain the proliferative phase.
AKA Construction phase
- Begins within 3 to 4 days after the initial injury, and continues for up to 2 weeks.
- 3 key changes occur
- Epithelization
- Granulation
- Angiogensis
What nutrient are thought to be ‘conditionally essential’ during the proliferative phase of healing?
AA: Arginine and glutamine
Why does iron have an important role in the proliferative phase?
- Plays a vital role in the formation of collagen requires the participation of iron as a cofactor
- Important for hemoglobin synthese
- Delivery of adequate oxygen via hemoglobin
- Collagen synthesis
- Fibroblastic proliferation
- Angiogensis
- Epithelization
Explain the maturation phase.
AKA Remodeling phase
- Collagen synthesis
- Tissue regeneration
- Wound contraction all continue and persist for many years.
- Scar tissue is remodeled, capillaries dissolve and the scar tissue gains strength (only up to 80% of original tensile strength)
What is ‘dysfunctional’ wound healing?
Occurs when healing steps are adversely affected or inhibited.
- Prolonged inflammatory state
- Reduced availablity of growth factors
- Increased burden (all contribute to wound chronicity)
- Underlying disease (DM)
- Prolonged bleeding
- Inadequate availability of nutrients and blood supply, prescribed drugs, hypoxemia, and inadequate energy intake.
What does a wound VAC do?
- Used to remove inflammatory substrates, excess interstitial fluid, and edema to promote improvements in tissue oxygenation.
- Associated with reduced infection and promotion for wound granulation.
Explain the difference between prevalence and incidence.
- Prevalence: a measure of the number of cases of pressure ulcers/injuries at a specific time
- Incidence: measures the number of NEW pressure ulcers/injuries in individuals without an ulcer/injury at baseline and is a better indication of quality of care.
What is a “never event?”
It is a term used by the CMS (Centers for Medicard and Medicaid Services) to deny payment for costs associated with select complications of patient care that could be prevented
- For example: Preexisting malnutrition was a positive predictive variable for pressure ulcer after a major surgery.
