Flashcards in Wound Healing: an overview Deck (24):
What are Acute Wounds? What are chronic wound?
examples of acute wounds are: surgical, traumatic
chronic wounds = pressure ulcer, vascular ulcer, diabetic
What are the 4 stages of wound healing?
Do acute and chronic go through the same wound healing stages?
Describe the Hemostasis stage
Damaged vessels must be sealed. The platelets act to seal off the damaged blood vessels. This stage occurs within minutes of the initial injury, unless they have a clotting disorder.
Describe the inflammation stage:
inflammation presents as erythema, swelling, and warmth often associated with pain. This stage usually lasts up to FOUR DAYS post injury. Clean up is done by neutrophils or PMNs. The inflammatory response causes the blood vessels to become leaky releasing plasma and PMNs into the surrounding tissue. The neutrophils phagocytize debris and microorganisms and provide the first line of defense against infection.
Describe the proliferation stage:
Macrophages are able to phagocytize bacteria and provide a second line of defense. They also secreted a variety of growth factors such as FGF and EGF, transforming growth factor beta and interleukin-1. This usually begins around 4 days after wounding, and usually lasts until day 21 in acute wounds depending on the size of the wound. It is characterized clinically by the presence of pebbled red tissue in the wound base and involves replacement sub dermal tissues in deeper wounds as well as contraction of the wound.
What are the different cells involved in the proliferation phase?
1. fibroblasts = secrete collagen framework on which further dermal regeneration occurs.
2. pericytes = regenerate the outer layers of the capillaries and the endothelial cells which produce the lining.
3. keratinocytes = responsible for epithalializtion.
In the final stage of epithelialization, contracture occurs as the keratinocytes differentiate to form the protective outer layer or stratum corneum.
describe the remodeling and maturation phase:
in wound repair the healing process involves remodeling the dermal tissues to produce greater tensile strength. The principle cell involved in this is the fibroblast. Remodeling can take up to 2 years after wounding and explains why apparently headed wounds can break down so dramatically and quickly if attention is not paid to the wounds causative factors.
In a healthy wound with no underlying factors, how long should it take to heal?
3 weeks, with remodeling occurring over the next year or so.
When does a wound become chronic?
When it does not follow the normal trajectory it may become stuck in one of the stages and become chronic.
Define chronic wounds:
wounds which have failed to proceed through an orderly and timely process to produce anatomic and functional integrity.
Once a wound is considered chronic, who needs to look at it to determine if there is an underlying cause?
a wound nurse or yourself.
What are three basic principles that should be used to support wound healing?
1. identify and control as best as possible the underlying causes.
2. support patient centered concerns
3. optimize local wound care.
What are some LOCAL factors that affect wound healing?
1infection, edema, ischemia/necrotic tissue in the wound, topical agents, ionizing radiation, low 02, foreign bodies.
what are some REGIONAL factors that affect wound healing?
arterial insufficiency, venous insuffiency, neuropathy.
what are some SYSTEMIC factors that affect wound healing?
inadequate perfusion, inflammation, nutrition, metabolic disease, immunosupppresed, smoking
Does a wound heal best in wet environment or a dry environment?
what are some reasons for why a wet environment heals better?
1. decreased dehydration and cell death
2. increased angiogenesis
3. enhanced autolytic debridement
4. increased re-epitheliazation
5. decreased infection rates
6. decreased pain
7. decreased cost
can neutrophils, macrophages, and pericytes function in a dry environment?
no, and it is their job to help initiate wound care
does angiogensi work better in a wet or dry environment?
wet, angiogenesis occurs twoards regions of low 02 tension such that occlusive dressings may act as a stimulus in the process.
wounds covered with a occlusive dressing have lower rates of ....
dressings should retain enough moisture to stimulate ________, and yet should not cause ______ or _____ to the surrounding tissues.
healing, maceration or irritation
What is the principle function of a wound dressing?
to provide an optimum healing environment.