Wound Healing
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Normal healing (3R's)
- Reaction: inflammatory process (72 hours)
- Regeneration: proliferation (up to three weeks)
- Remodeling: (three weeks to two years)
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Black wound: most often in late reaction or early regeneration phase
- Macrophages are migrating to injury to clean up bacteria and debris
- Growth factors stimulating new vascular growth at wound base (angiogenesis), fibroblast migration and fibroblast proliferation
- Collagen being deposited, filling wound with scar tissue
- If eschar left intact and kept dry:
- cellular debris will escape wound edges as necrotic tissue begins to separate from granulation tissue
- usually only inflamed around edges
- If eschar becomes contaminated:
- becomes excellent medium for infection
- wound remains in reaction or inflammatory stage
- systemic signs of infection
- Eschar delays regeneration phase by interfering with cell migration and wound closure
- Risk of wound infection increases as the amount of necrotic tissue increases
- Needs debridement
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Yellow wound (yellow necrosis or slough): tissue not damaged enough to form an eschar so wound covered with thick yellow fibrous debris or viscous exudate
- Usually in late reaction or early regeneration
- High risk of infection due to excellent medium for bacterial growth
- Regeneration phase continuing with earlier wound contraction than with the thick eschar
- Needs continuing debridement
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Red wound: if chronic usually in late regeneration or remodeling phase. Red indicates presence of granulation tissue.
- Color of granulation tissue affected by nutritional status and blood supply
- full thickness ulcer: crater with pale pink to beefy red granulation tissue
- crater slowly fills with granulation tissue from bottom upward
- Wound contraction and epithelialization continues. Epithelialization occurs from wound edges inward.
- Color of granulation tissue affected by nutritional status and blood supply