Wound Healing and Care

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Phases of Healing - Speedy Recovery Stages

  • Hemostasis: Immediate. Vasoconstriction, platelet aggregation (plug), coagulation cascade activation → fibrin clot.
  • Inflammation (Substrate Phase): Days 1-4. Neutrophils (peak 24-48h), followed by Macrophages (key for transition). Phagocytosis, cytokine release.
  • Proliferation (Fibroblastic Phase): Day 3 to 3 weeks. Fibroblasts deposit Collagen Type III. Angiogenesis (new vessels), granulation tissue. Epithelialization. Myofibroblasts cause wound contraction.
  • Remodeling (Maturation Phase): 3 weeks to 1-2 years. Collagen Type III gradually replaced by stronger Type I. ↑ Tensile strength. Scar flattens.

⭐ Maximum tensile strength achieved is about 70-80% of original tissue, typically by 3 months.

Phases of wound healing diagram

Types of Healing - Gap Closing Goals

  • Primary Intention: Clean wound, edges apposed (sutured). Minimal tissue loss. Goal: Rapid closure, fine scar.
  • Secondary Intention: Edges not apposed, large defect. Heals by granulation, contraction, epithelialization. Goal: Body heals open wound.

    ⭐ Myofibroblasts are key for wound contraction in secondary intention.

  • Tertiary Intention (Delayed Primary Closure): Initially left open (e.g., due to contamination), later surgically closed. Goal: Manage issues (infection), then close.

Factors Affecting Healing - Repair Roadblocks

  • Local Factors:
    • Infection (Most common delay)
    • Poor perfusion/Hypoxia (pO₂ < 40mmHg impairs collagen synthesis)
    • Foreign body, Hematoma, Seroma, Necrotic tissue
    • Trauma, Tension
    • Radiation, Edema
  • Systemic Factors:
    • Age (Advanced: ↓cell activity, ↓collagen)
    • Nutrition: ↓Protein, ↓Vit C, ↓Vit A, ↓Zinc, ↓Copper
    • Diabetes (DM) (↓PMN function, ↓angiogenesis, ↓collagen)
    • Meds: Steroids (↓inflammation, ↓collagen), Chemo, NSAIDs (early)
    • Smoking (↓O₂ delivery, ↑CO), Obesity (↓perfusion)
    • Systemic Illness: Uremia, Jaundice, Malignancy, Anemia (Hb < 10g/dL)

Normal vs. Chronic Wound Healing

Vitamin C is crucial for hydroxylation of proline and lysine, essential for collagen cross-linking; deficiency leads to impaired healing and scurvy.

Wound Care Principles - Bandage & Beyond

  • Dressing Goals: Protect, absorb exudate, debride, compress, deliver medication.
  • Dressing Types & Key Uses:
    • Gauze: Packing, absorption.
    • Films (e.g., Tegaderm): Superficial wounds, autolytic debridement, visualization.
    • Foams: Moderate/heavy exudate, cushioning.
    • Hydrocolloids (e.g., Duoderm): Autolytic debridement, light/moderate exudate, occlusive.
    • Alginates: Heavy exudate, hemostatic, cavity wounds.
    • Hydrogels: Hydrate dry/necrotic wounds, slough removal.
  • Negative Pressure Wound Therapy (NPWT/VAC):
    • Mechanism: Subatmospheric pressure (typically -75 to -125 mmHg).
    • Benefits: ↓edema, ↑granulation tissue, ↑perfusion, ↓bacterial load.
    • Indications: Acute, chronic, traumatic wounds; grafts/flaps.
    • ⚠️ Contraindications: Malignancy in wound, untreated osteomyelitis, non-enteric/unexplored fistulas, necrotic tissue with eschar, exposed vessels/organs.
  • Bandaging: Apply distal to proximal; even, firm pressure; avoid tourniquet effect.

Wound Dressing Types, Materials, Advantages, Indications

⭐ NPWT is generally contraindicated directly over exposed blood vessels, nerves, anastomotic sites, or organs due to risk of erosion or fatal hemorrhage. Use a protective barrier if unavoidable and monitor closely.

Complications of Healing - Scar Wars

  • Hypertrophic Scar: Raised, red, itchy. Develops within weeks.
  • Keloid: Rubbery, overgrows boundaries. Develops months later. Common in darker skin. 📌 KELOID: Keeps Extending.
  • Contractures: Limit movement, deformity. Esp. joints, burns.
  • Ulceration: Chronic non-healing.

    ⭐ Marjolin's ulcer: SCC in chronic wounds, burn scars, osteomyelitis sinuses.

  • Others: Dyspigmentation, persistent pain, pruritus. Hypertrophic vs Keloid Scar Comparison

High‑Yield Points - ⚡ Biggest Takeaways

  • Healing Phases: Inflammatory (PMNs, MΦ), Proliferative (fibroblasts, new vessels), Remodeling (collagen I for III).
  • Collagen Facts: Type III (early) replaced by Type I (strong); max strength ~80% at 3 months.
  • Wound Closure: Primary (sutured), Secondary (granulation), Tertiary (delayed primary).
  • Major Inhibitors: Infection, hypoxia, malnutrition (Vit C, zinc), diabetes, steroids.
  • Problematic Scars: Keloids grow beyond wound; Hypertrophic scars stay within boundaries.
  • Myofibroblasts: Crucial for wound contraction, especially in secondary intention healing.

Practice Questions: Wound Healing and Care

Test your understanding with these related questions

A forest officer develops the lesion as shown in the image. Which of the following is not a differential to consider?

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Flashcards: Wound Healing and Care

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_____ is used in the closure of sternotomy wound.

TAP TO REVEAL ANSWER

_____ is used in the closure of sternotomy wound.

Surgical steel

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