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Fontano , Michael Jeff Gagtan , Majelle Garcia, Kristina Fatima Louise. WOUND HEALING. Hemostasis and Inflammation Proliferation Maturation and Remodelling. PHASES OF WOUND HEALING. - PowerPoint PPT Presentation
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WOUND HEALING
Fontano, Michael JeffGagtan, MajelleGarcia, Kristina Fatima Louise
PHASES OF WOUND HEALING Hemostasis and Inflammation
Proliferation
Maturation and Remodelling
HEMOSTASIS AND INFLAMMATION Exposure of subendothelial collagen to platelets
results in platelet aggregation, degranulation, and activation of the coagulation cascade
Platelet -granules release a number of wound-active substances platelet-derived growth factor (PDGF) transforming growth factor beta (TGF) platelet-activating factor, Fibronectin serotonin
HEMOSTASIS AND INFLAMMATION
HEMOSTASIS AND INFLAMMATION fibrin clot
scaffolding for the migration into the wound of inflammatory cells such as polymorphonuclear leukocytes (PMNs, neutrophils) and monocytes
PMNs first infiltrating cells to enter the wound
site Peak: 24 to 48 hours.
HEMOSTASIS AND INFLAMMATION• Neutrophil
― phagocytosis of bacteria and tissue debris― major source of cytokines early during inflammation (TNF)― release proteases such as collagenases (participate in matrix
and ground substance degradation in the early phase of wound healing)
― implicated in delaying the epithelial closure of wounds
• Stimulants for Neutrophil migration― increased vascular permeability― local prostaglandin release― presence of chemotactic substances, such as complement
factors, interleukin-1 (IL-1), tumor necrosis factor alpha (TNF-), TGF, platelet factor 4, or bacterial products
HEMOSTASIS AND INFLAMMATION Macrophages
achieve significant numbers in the wound by 48 to 96 hours postinjury and remain present until wound healing is complete
wound débridement via phagocytosis c contribute to microbial stasis via oxygen radical
and nitric oxide synthesis activation and recruitment of other cells via
mediators (cytokines and growth factors) as well as directly by cell–cell interaction and intercellular adhesion molecules
regulating angiogenesis and matrix deposition and remodeling
PROLIFERATION days 4 through 12 tissue continuity is re-established Fibroblasts and endothelial cells
last cell populations to infiltrate the healing wound
strongest chemotactic factor for fibroblasts is PDGF
PROLIFERATION Endothelial cells
proliferate extensively during this phase of healing
participate in the formation of new capillaries (angiogenesis),
MATURATION AND REMODELLING begins during the fibroplastic phase characterized by a reorganization of
previously synthesized collagen wound strength and mechanical
integrity in the fresh wound are determined by both the quantity and quality of the newly deposited collagen
MATURATION AND REMODELLING Deposition of matrix
Fibronectin and collagen type III- early matrix scaffolding
glycosaminoglycans and proteoglycans- next significant matrix components
collagen type I is the final matrix.
MATURATION AND REMODELLING Scar remodeling continues for many (6
to 12) months postinjury, gradually resulting in a mature, avascular, and acellular scar.
The mechanical strength of the scar never achieves that of the uninjured tissue.
DRESSINGS
DRESSINGS Provides ideal environment for wound
healing Mimics the barrier role of epithelium
and prevents further damage Provides hemostasis and limits edema Controls the level of hydration and
oxygen tension within the wound Allows transfer of gases and water
vapor from the wound surface to the atmosphere
DESIRED CHARACTERISTICS OF WOUND DRESSINGS
Promote wound healing Conformability Pain control Odor control Non allergenic and non irritating Permeability to gas Safety Nontraumatic removal Cost efffectiveness convenience
CLASSIFICATION OF DRESSINGS1. Primary – placed directly on the wound
and may provide absorption of fluids and prevent dessication, infection, and adhesion of a secondary dressing
2. Secondary – placed on a primary dressing for further protection, absorption, compression and occlusion
ABSORBENT DRESSINGS Absorb without getting soaked Designed to match the exudative
properties of the wound and may include cotton, wool, and sponge.
NONADHERENT DRESSINGS Impregnated with paraffin, petroleum
jelly, or water soluble jelly for use as nonaddherent coverage
Secondary dressing must be placed on top to seal edges to prevent dessication and infection
OCCLUSIVE AND SEMI OCCLUSIVE DRESSINGS
Provide good environment for clean, minimally exudative wounds
Waterproof and impervious to microbes, but permeable to water vapor and oxygen
HYDROPHILIC AND HYDROPHOBIC DRESSINGS
Components of a composite dressingHydrophilic – aids in absorptionHydrophobic – waterproof and
prevents absorption from light to heavy wounds
HYDROCOLLOID AND HYDROGEL DRESSINGS
Combination of occlusion and absorbency Form complex structures with water and fluid
absorption occurs with particle swelling, which aids in atraumatic removal of dressingHydrocolloid - for light to moderate acute and chronic woundsHydrogel - for burns(including those caused by radiation) skins tears, surgical wounds, and pressure ulcers.
ALGINATES From brown algae with polysaccharides
containing mannuronic and glucoronic acid Polymers gel, swell and and absorb great
deal of fluid Used when there is skin loss, in open
surgical wounds with medium exudation and on full thickness chronic wounds
for moderate to heavy wounds, because of their superior absorption ability
MEDICATED DRESSINGS Used as drug-delivery system, agents
like benzoyl peroxide, zinc oxide, neomycin, and bacitracin-zinc
Shown to increase epithelialization by 28%
Used depends on the amount of wound drainage
Absorbent
Hydrocolloid
Hydrophobic
Semi occlusive
Occlusive