Wound Healing Flashcards
Wound classification
Clean- surgical wounds without entering viscus
Clean-contaminated- viscus entered, but under controlled situation
Contaminated- gross contamination, no obvious infection ,most traumatic wounds.
Dirty- Obvious infection
Primary Wound Closure
First intention healing. Apposition of wound edges. Most surgical wounds.
Delayed Primary Wound
Closure 3-5 days after wounding. Before granulation formation. Mildly contaminated wounds with minimal trauma. Need some cleansing, debridement, and open wound management before closure.
Secondary wound closure
Closure >3-5 days after. Granulation tissue formed. Indications for severely contaminated, traumatized wounds.
Second Intention
Wound heals by contraction and epithelialization. Problems- excessive wound contamination, failure to completely re-epithelialize. Over proliferation of granulation tissue.
Phases of wound healing
Inflammation, Proliferation, maturation.
Phase 1
Inflammatory phase- hemostasis, early and late inflammation
Phase 1- early inflammation
24-48 hours
Vasodilation, increased endothelial cell permeability, Leukocyte extravasation. Heat, redness, swell, pain, loss of function.
Vasodilation- occurs within minutes. Increased blood flow and local delivery of soluble mediators and inflammatory cells.
Cell permeability- stimulated by hypoxia, endothelial injury, cytokines
Leukocyte extravasation- margination, rolling, stable adhesion, migration
Neutrophils
Phase 1- late inflammation
48-72 hours
Macrophages.
Pro to anti-inflammatory
Phase 2- Proliferation
Phase 2: Angiogenesis and fibroplasia= granulation tissue. Contraction and epithelialization
Angiogenesis- Stimualted by cytokines. Invading microvascular within 4-6 days.
Fibroplasia- Mesenchymal cells to fibroblasts. 2-5 days. Synthesize collagen (dependent on oxygen and provides tensile strength)
Fibroplasia+ angiogenesis= granulation. Begins 6-7 days. Occurs within ECM.
Contraction- fibroblasts anchored-> myofibroblasts. 6-14 days. Orientate along lines of tension and attack to ECM. Apoptosis after 4-5 weeks
Epithelialization- keratinocytes and epithelial cells. Migrate across wound and contact inhibition. Wound closure
Phase 3: maturation
Collagen reorganization. Scar formation- never 100%
Impaired Wound Healing
Local factors- wound perfusion, tissue viability, fluid accumulation, infection, tension. Motion, pressure
Systemic- impaired immune function, cancer
Impaired Wound- Wound Perfusion
Shock, hypotension, hypovolemia. Severe trauma. Oxygen vital for wound healing and resistance to infection. Promote perfusion by fluid rehydration, prevent hypothermia, hyperbaric oxygen
Wound healing- tissue viability
Significant loss of soft tissue. Devitalized or necrotic tissue and foreign debris, prolongs the inflammatory phase, appropriate debridement
Wound healing- fluid accumulation
Hematoma or seroma. Pressure inside wound. Enlarged dead space. Ideal media for bacterial proliferation.
Wound healing- motion and tension
Disrupt and prolong healing. Avoid with appropriate bandages, partial or complete wound closure, or negative pressure.
Wound healing- immune disorder
Attenuated inflammatory response, impaired chemotaxis, and inefficient bacterial killing
Endocrine disorders- Cushing, DM, FIV
Nutrition
Debridement
Surgical, mechanical (dressings), biologic (maggots), or enzymatic (collagenase impregnated dressings)
Adherent dressings
Dry to dry or wet to dry. Mechanical debridement. Change frequently.
Hyperosmotic dressings- Hypertonic saline
use during inflammatory phase, early proliferation, at any stage if wound infected.
20% hypertonicity- antimicrobial, facilitates autolytic debridement.
Hyperosmotic dressings- Honey
Use during inflammation or early proliferation. Antibacterial. Enhances autolytic debridement. Reduce edema and inflammation. Enhance granulation tissue and epithelialization. Good with burns.
Hyperosmotic dressings- Sugar
Use during inflammatory and early proliferation phase. Hyperosmotic to decrease edema. Cheap. Not to sue with healthy granulation tissue and epithelial tissue
Debridement- enzymatic agents
Use during inflammatory and early proliferation. Superficial debridement of poor granulation tissue in chronic wounds. Collagenase.
Debridement- maggots
Inflammatory or early inflammation. Secrete digestive enzymes to dissolve necrotic tissue. Can destroy healthy epithelium
