WOUND HEALING

1. Fontano, Michael Jeff Gagtan, Majelle Garcia, Kristina Fatima Louise WOUND HEALING

2. Hemostasis and Inflammation Proliferation Maturation and Remodelling PHASES OF WOUND HEALING

3. 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

5. Hemostasis and Inflammation

6. 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

7. 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

8. 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 Hemostasis and Inflammation

9. 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

10. Endothelial cells • proliferate extensively during this phase of healing • participate in the formation of new capillaries (angiogenesis), Proliferation

11. 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

12. 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

13. 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. Maturation and Remodelling

14. DRESSINGS

15. 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 DRESSINGS

16. Promote wound healing Conformability Pain control Odor control Non allergenic and non irritating Permeability to gas Safety Nontraumatic removal Cost efffectiveness convenience DESIRED CHARACTERISTICS OF WOUND DRESSINGS

17. Primary – placed directly on the wound and may provide absorption of fluids and prevent dessication, infection, and adhesion of a secondary dressing Secondary – placed on a primary dressing for further protection, absorption, compression and occlusion CLASSIFICATION OF DRESSINGS

18. Absorb without getting soaked Designed to match the exudative properties of the wound and may include cotton, wool, and sponge. ABSORBENT DRESSINGS

19. 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 NONADHERENT DRESSINGS

20. Provide good environment for clean, minimally exudative wounds Waterproof and impervious to microbes, but permeable to water vapor and oxygen OCCLUSIVE AND SEMI OCCLUSIVE DRESSINGS

21. Components of a composite dressing Hydrophilic – aids in absorption Hydrophobic – waterproof and prevents absorption from light to heavy wounds HYDROPHILIC AND HYDROPHOBIC DRESSINGS

22. Combination of occlusion and absorbency Form complex structures with water and fluid absorption occurs with particle swelling, which aids in atraumatic removal of dressing Hydrocolloid - for light to moderate acute and chronic wounds Hydrogel - for burns(including those caused by radiation) skins tears, surgical wounds, and pressure ulcers. HYDROCOLLOID AND HYDROGEL DRESSINGS

23. 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 ALGINATES

24. 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 MEDICATED DRESSINGS

25. Alginates Hydrogel Hydrophilic Nonabsorbent

26. Hydrophobic Hydrocolloid Semi occlusive Absorbent Occlusive