Phases of Healing - Repair Relay Race
- 0. Hemostasis (Immediate):
- Vasoconstriction, platelet plug, fibrin clot.
- 1. Inflammatory Phase (Day 1-6): "Clean-up Crew"
- Neutrophils (PMNs) (24-48h): clear debris, bacteria.
- Macrophages (48-96h): phagocytosis, release growth factors (GFs).
- 2. Proliferative Phase (Day 4 - Wk 3): "Rebuilding Zone"
- Fibroblasts: Type III collagen. Angiogenesis (granulation tissue).
- Epithelialization. Myofibroblasts: initiate wound contraction.
⭐ Type III collagen (predominant in early granulation tissue) is replaced by Type I collagen for tensile strength.
- 3. Remodeling Phase (Wk 3 - Months/Years): "Maturation & Strength"
- Collagen conversion: Type III → Type I.
- Tensile strength ↑ (max ~80% of original skin).
- Scar matures and reorganizes. 📌 Mnemonic: Healers Initiate Progress & Remodel (HIPR).
Wound Assessment & Types - Spotting Trouble
- Assessment:
- History: Mechanism (blunt/sharp), time since injury, contamination level, tetanus status.
- Exam: Location, size (L x W x D), edges (everted/inverted), base (viable?), exudate (type, amount), odor.
- Infection signs (local): Redness, warmth, swelling, pain, discharge (pus).
- Systemic: Fever (>38°C), ↑WBC, tachycardia.
- Wound Classification (CDC):
- Class I (Clean): <2% SSI risk. E.g., hernia repair.
- Class II (Clean-Contaminated): 3-5% SSI risk. E.g., elective GI surgery.
- Class III (Contaminated): 10-15% SSI risk. E.g., open fracture <4h.
- Class IV (Dirty/Infected): 20-40% SSI risk. E.g., perforated viscus.
⭐ Most surgical site infections (SSIs) manifest between the 5th and 10th postoperative day.
- Spotting Trouble - TIME Framework (📌 Mnemonic):
- Tissue: Non-viable or deficient.
- Infection or Inflammation.
- Moisture imbalance: Too dry or too wet.
- Edge of wound: Non-advancing or undermined.
Management Principles - Debride & Defend
- Goal: Convert contaminated/chronic wound to clean acute wound.
- Debridement: Removal of necrotic, devitalized tissue, foreign material & bacteria. Promotes healing by reducing inflammation & infection risk.
- Types: 📌 SAD MEchanical, Surgical (Sharp), Autolytic, Debriding agents (Enzymatic), Maggot (Biosurgical), Electrical (Ultrasonic).
- Defend (Antimicrobials): Indicated for infected wounds or high-risk clean-contaminated wounds.
- Topical: Silver sulfadiazine, mupirocin, povidone-iodine (use judiciously).
- Systemic: Based on culture & sensitivity if signs of spreading infection.
⭐ Negative Pressure Wound Therapy (NPWT) is contraindicated over exposed blood vessels, nerves, anastomotic sites, organs, or malignancy in the wound. It promotes granulation tissue formation by applying sub-atmospheric pressure (typically -125 mmHg).
Dressings Deep Dive - Material Matters
Choice depends on wound type, exudate, depth, infection. Goal: optimal healing environment.
| Dressing Type | Key Property | Primary Use | 📌 Mnemonic/Tip |
|---|---|---|---|
| Gauze | Absorbent, permeable | Packing, cleaning, cover (dry/wet) | "Good old Gauze" |
| Transparent Films | Semi-permeable, allows inspection | Superficial wounds, IV sites, secondary dressing | "See-Thru Shield" |
| Foams | Highly absorbent, cushioning | Moderate-heavy exudate, pressure ulcers | "Fluffy Foam" |
| Hydrocolloids | Occlusive, promotes autolysis, gel-forming | Light-moderate exudate, non-infected | "Colloid Cloud" |
| Hydrogels | Hydrating (high water content), cooling | Dry, sloughy, necrotic wounds, burns | "Gel Quench" |
| Alginates | Highly absorbent (forms gel), haemostatic | Heavy exudate, cavity wounds, bleeding | "Algae Absorb" |
| Silver Dressings | Antimicrobial (Ag+) | Infected wounds, high-risk wounds | "Silver Sentry" |
| Honey Dressings | Antimicrobial, osmotic, debriding | Infected, sloughy wounds, burns | "Honey Healer" |
High‑Yield Points - ⚡ Biggest Takeaways
- Wound healing phases: Inflammatory (0-3d), Proliferative (3d-3wks), Remodeling (3wks-2yrs).
- Primary intention for clean, approximated wounds; Secondary intention for open wounds, heals by granulation.
- Tertiary intention (delayed primary closure) for initially contaminated wounds closed later.
- NPWT (Negative Pressure Wound Therapy) promotes granulation and reduces edema.
- Alginates for heavy exudate; Hydrocolloids for moderate exudate, autolytic debridement.
- Wound infection signs: Erythema, warmth, pain, purulent discharge, systemic fever.
- Optimal healing requires adequate protein, Vitamin C, and Zinc.
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