Burn Study Guide

📖 Core Concepts Burn – injury to skin or deeper tissue from heat, electricity, chemicals, friction, or radiation. Depth – Superficial (1°): epidermis only, red, no blisters. Partial‑thickness (2°): into dermis, painful, blisters. Full‑thickness (3°): all skin layers, often painless, stiff. Fourth‑degree: muscle‑tendon‑bone involvement. TBSA (Total Body Surface Area) – percentage of body burned; guides fluid needs and predicts mortality. Rule of Nines – adult TBSA estimate (head = 9 %, each arm = 9 %, each leg = 18 %, front trunk = 18 %, back trunk = 18 %, perineum = 1 %). Lund‑Browder chart – child‑specific TBSA chart (more accurate for pediatric patients). Parkland Formula – initial crystalloid volume: $$\text{Fluid (mL)} = 4 \times \text{weight (kg)} \times \text{TBSA (\%)}$$ Half in first 8 h, remainder over next 16 h. Inhalation injury – airway damage from hot gases; dramatically raises mortality. Hypermetabolic response – ↑ catecholamines/cortisol → ↑ cardiac output, O₂ consumption, protein catabolism for weeks to months. --- 📌 Must Remember Mortality: < 1 % if TBSA < 10 %; up to 85 % if TBSA > 90 %. Cooling: 10–25 °C water, ≤ 30 min post‑injury; do NOT use ice water. Fluid Goal: urine > 30 mL/h (adult) or > 1 mL/kg/h (peds); MAP > 60 mmHg. Airway: early intubation for any sign of inhalation injury (hoarseness, stridor, singed nasal hair). Tetanus: give toxoid if > 5 yr since last booster. Dressings: routine silver sulfadiazine not recommended for most burns; may delay healing. Escharotomy: indicated for circumferential burns causing vascular or respiratory compromise. Nutrition: start enteral feeding within 24 h; protein 1.5–2 g/kg/day, calories 30–45 kcal/kg/day. Baux Score (historical): Age + TBSA ≈ % mortality (less accurate with modern care). --- 🔄 Key Processes Primary Survey (ABCD‑E) Airway → look for soot, singed hair, stridor. Breathing → assess oxygenation, consider early intubation. Circulation → start IV, monitor pulse, BP. Disability → neuro status. Exposure → fully expose patient, prevent hypothermia. TBSA Estimation Use Rule of Nines (adult) or Lund‑Browder (child). 1 hand‑print ≈ 1 % TBSA (quick bedside check). Fluid Resuscitation (Parkland) Calculate total volume (4 × kg × %TBSA). Give ½ in first 8 h from time of burn (not from admission). Adjust based on urine output and MAP. Cooling the Burn Apply cool (10–25 °C) water for 10–20 min. Remove contaminated clothing; avoid ice. Wound Management Clean with mild soap/water; irrigate chemicals thoroughly. Assess blisters: leave small intact, debride large ones. Apply appropriate dressing (foam for partial‑thickness; consider silver‑containing only when infection risk high). Surgical Decision Full‑thickness → early excision + autograft. Circumferential limb/chest → escharotomy before grafting. Nutrition Initiation Start enteral feeding within 24 h; monitor glucose, electrolytes. --- 🔍 Key Comparisons Superficial (1°) vs Partial‑thickness (2°) vs Full‑thickness (3°) Depth: epidermis | epidermis + dermis | epidermis + dermis + subdermal structures Pain: painful | painful + blisters | often painless (nerve destruction) Healing: 3 days, no scar | up to 8 weeks, may scar | requires grafting, permanent scar High‑voltage (≥ 1000 V) vs Low‑voltage (< 1000 V) Electrical Burns Internal damage: extensive, may be occult | usually limited to entry/exit sites Complications: arrhythmias, compartment syndrome, rhabdomyolysis | less systemic risk Ice Water Cooling vs Cool Water Cooling Ice → vasoconstriction, deeper injury, hypothermia risk Cool water → limits depth, provides analgesia, safe Silver Sulfadiazine vs Modern Dressings Silver sulfadiazine: broad antimicrobial but may delay epithelialization Modern moist dressings (foam, biosynthetic): promote faster healing, less scarring --- ⚠️ Common Misunderstandings “Ice is best for burns.” → Ice causes vasoconstriction and can worsen tissue injury. Use cool water only. “All burns need prophylactic antibiotics.” → Only indicated for > 60 % TBSA before surgery, inhalation injury, or confirmed infection. “Silver sulfadiazine should be used on every burn.” → Not routine; may impede healing, especially for partial‑thickness burns. “Give the full Parkland volume immediately.” → Half the volume must be given in the first 8 h from injury time, not admission time. “A burn that looks deep is always full‑thickness.” – Depth may evolve; reassess over 24–48 h. --- 🧠 Mental Models / Intuition “Hand = 1 % TBSA” – Quick bedside estimate for irregular burns. “Fire + Face + Soot = Inhalation injury” – Any facial burn with soot warrants airway evaluation. “Cold water → shallow; ice → deep” – Remember the temperature range for safe cooling. “Fluid = 4 × kg × %TBSA” – Parkland’s “4‑formula” mnemonic. --- 🚩 Exceptions & Edge Cases Children: Use Lund‑Browder chart; higher surface‑area‑to‑mass ratio → faster fluid loss. Electrical burns: Skin may look minor; always assess for deep tissue injury, rhabdomyolysis, compartment syndrome. Chemical burns: Some agents (e.g., hydrogen fluoride) need specific antidotes (calcium gluconate). Burns > 30 % TBSA: Trigger systemic inflammatory response; monitor for burn shock, renal failure, and hypermetabolism. Pregnant patients: Fluid resuscitation goals unchanged, but monitor uteroplacental perfusion closely. --- 📍 When to Use Which Airway management – Intubate if any stridor, hoarseness, facial burns, or soot in mouth. Fluid type – Start with Lactated Ringer’s (balanced electrolyte load); switch to colloids only if refractory hypotension after adequate crystalloid. Dressings – Foam or hydrocolloid for superficial partial‑thickness; consider silver‑containing only for high infection risk or colonized wounds. Antibiotics – Reserve for > 60 % TBSA pre‑op, inhalation injury, or documented infection. Surgical grafting – Indicated for any full‑thickness burn > 24 h old or when spontaneous healing unlikely. Escharotomy – Perform when circumferential burn limits distal pulses or impairs ventilation. --- 👀 Patterns to Recognize Inhalation injury: facial burns + soot + hoarseness → early airway compromise. Burn shock: rapid tachycardia, low MAP, decreasing urine output within first 24 h. Hypermetabolism: persistent high fevers, catabolism, delayed wound healing > 2 weeks post‑injury. Infection risk: TBSA > 30 %, full‑thickness, perineal or leg involvement → higher colonization. --- 🗂️ Exam Traps “Apply ice to stop the pain.” – Wrong; ice worsens injury. “All burns need silver sulfadiazine.” – Incorrect; not first‑line for most partial‑thickness burns. “Give the entire Parkland volume immediately.” – Misreading; half must be given in the first 8 h from injury. “Any burn > 5 % TBSA needs fluid resuscitation.” – Only > 15 % (adult) or > 10–20 % (child) triggers formal resuscitation. “A burn that looks deep is automatically full‑thickness.” – Depth can be misjudged; reassess over time. “Prophylactic antibiotics for all burns.” – Overuse leads to resistance; only specific indications. ---