Burns - Comprehensive Surgical Notes

1. BACKGROUND & EPIDEMIOLOGY

• Scald burns - most common in young children (<5 yrs)
• Flame burns - more common in teenagers and adults
• Contact, electrical, chemical, radiation burns

2. ABA CRITERIA FOR BURN CENTER REFERRAL

3. INITIAL EVALUATION - PRIMARY SURVEY (ATLS)

1. Airway management
2. Evaluation of other injuries
3. Estimation of burn size (%TBSA)
4. Diagnosis of CO and cyanide poisoning

Airway

• Rapid, severe airway edema from direct thermal injury or smoke inhalation is potentially lethal
• Establish early airway if in doubt - do NOT wait
• Warning signs: hoarse voice, wheezing, stridor, subjective dyspnea (especially alarming)
• Perioral burns and singed nasal hairs alone do NOT indicate upper airway injury but warrant examination of mucosa
• Orotracheal intubation is preferred; nasotracheal is an option only with experienced providers and facial trauma
• Pediatric airway: small cross-section makes it prone to rapid collapse with edema; fiberoptic bronchoscopy is gold standard for evaluation when uncertain
• Empirical 100% O2 while obtaining ABG and carboxyhemoglobin

IV Access

• Two large-bore IVs + Foley catheter placed immediately
• Resuscitation started promptly

4. BURN CLASSIFICATION

By Depth (Dupuytren's original 1832 classification)

Key point: superficial (1st degree) burns are NOT counted in %TBSA estimates.

5. ESTIMATING BURN SIZE - %TBSA

Rule of Nines (Adults)

Lund-Browder Chart

• More accurate, especially in children
• Adjusts for age-related changes (head is proportionally larger in infants; legs smaller)

Palmar Method

• Patient's palm (including fingers) = ~1% TBSA
• Useful for scattered or irregular burns

6. PROGNOSIS - BAUX SCORE

• Original Baux Score: predicted mortality % ≈ age + %TBSA
• Revised Baux Score adds 17 points if inhalation injury is present
• A score >140 traditionally associated with near-100% mortality, though modern burn centers have improved outcomes significantly
• LD50 (lethal dose causing 50% mortality): now >60-70% TBSA in specialized centers (was historically much lower)

7. FLUID RESUSCITATION

• Plasma loss into interstitium (burn and non-burn tissue)
• Hypovolemia and shock
• Edema

Parkland Formula (most widely used)

• First 8 hours: give ½ total volume (from time of burn, not admission)
• Next 16 hours: give remaining ½

Brooke Formula

Modified Brooke Formula

Key Resuscitation Principles

• Urine output is the primary titration target:
  • Adults: 0.5 mL/kg/h
  • Children >30 kg: 0.5 mL/kg/h
  • Children <30 kg: 1 mL/kg/h
• Lactated Ringer's is preferred (isotonic crystalloid)
• Avoid excess free water (hyponatremia risk)
• Second 24 hours: add colloid (albumin), decrease crystalloid
• Beware "fluid creep" - tendency to over-resuscitate, leading to abdominal compartment syndrome, pulmonary edema, extremity compartment syndrome

Colloid

• Not recommended in first 24 hours (theoretical worsening of leak)
• After 24 hours, albumin (5%) reduces ongoing crystalloid requirements

Endpoints of Resuscitation

• Urine output (primary)
• Blood pressure, heart rate
• Base deficit / lactate clearance
• Bladder pressures (monitor for abdominal compartment syndrome)

8. INHALATION INJURY

A. Upper Airway Injury (supraglottic)

• Direct thermal injury
• Causes rapid, severe edema
• Managed with early intubation

B. Lower Airway Injury (subglottic / tracheobronchial)

• Caused by toxic products of combustion (not heat - steam is rarely inhaled below glottis)
• Bronchospasm, mucosal edema, mucosal sloughing, impaired mucociliary clearance
• Leads to: bronchopneumonia, ARDS
• Bronchoscopy is gold standard for diagnosis

C. Systemic Toxins

• CO has ~200-250x greater affinity for hemoglobin than O2
• Decreases oxyhemoglobin, causes anoxia
• Also: uncoupling of oxidative phosphorylation, free radical generation, platelet activation, increased inflammatory response
• Pulse oximetry is falsely elevated (cannot distinguish COHb from OHb) - must check arterial COHb
• Symptoms: headache, confusion, syncope, cardiac arrhythmias, neurological sequelae
• Treatment: 100% normobaric oxygen - reduces CO half-life from 250 min (room air) to 40-60 minutes
• Hyperbaric oxygen: proposed for severe cases but meta-analysis shows mixed results; logistically difficult for large burns; cardiac arrest from CO = extremely poor prognosis

• From combustion of nitrogen-containing materials (wool, nylon, polyurethane)
• Inhibits cytochrome oxidase → blocks oxidative phosphorylation
• Presents with: severe persistent lactic acidosis, neurological symptoms, pulmonary edema, ST elevation on ECG
• Classic signs (bitter almond breath, cherry-red skin) are rare and unreliable
• Treatment: Hydroxocobalamin (vitamin B12 precursor) - rapidly complexes with cyanide, excreted renally; first-line for acute therapy. Sodium thiosulfate - substrate for cyanide metabolism; works slowly, useful as adjunct

Ventilator Management for Inhalation Injury

• Lung-protective ventilation: tidal volume 6 mL/kg ideal body weight (ARDS Network protocol)
• Traditional 12 mL/kg → 22% higher mortality (ARDS Network Study)
• Refractory hypoxemia: consider prone positioning (logistically challenging with burns, especially facial)
• High-frequency oscillatory ventilation (HFOV) - adjunct option
• ARDS contributes to mortality; modern deaths more often from multisystem organ failure

9. TREATMENT OF THE BURN WOUND

Wound Care Principles

• Cover wounds with dry sheet initially during assessment
• Do NOT debride during primary survey
• Remove all clothing and jewelry
• Irrigate chemical burns copiously with water

Topical Antimicrobials

Prophylactic Antibiotics

• Routine prophylactic systemic antibiotics are NOT recommended (ABA guideline)
• Increases antibiotic resistance without proven benefit for clean burns
• Antibiotics used when signs of infection develop

10. SURGICAL MANAGEMENT

Early Excision and Grafting

• Paradigm shift: early tangential excision (within 48-72 hours, ideally within first 1-2 weeks) dramatically improved survival
• Early excision removes necrotic tissue, reduces inflammatory mediators, reduces bacterial burden
• Historically, waiting for "auto-escharectomy" (spontaneous separation) was standard; led to wound sepsis

Tangential Excision

• Sequential thin slices until viable bleeding tissue seen
• Risk: significant blood loss (estimated 100-200 mL per 1% TBSA excised)
• Performed in staged fashion - typically no more than 20% TBSA per session
• Tourniquets used for extremities to reduce blood loss
• Tumescent technique with dilute epinephrine also used

Fascial Excision

• Reserved for very deep or infected burns
• Removes all tissue down to fascia
• Less blood loss but results in contour deformity

Wound Coverage Options

• Split-thickness skin graft (STSG) - harvested from donor sites (thigh, scalp, back)
• Meshed grafts (1.5:1 to 3:1 ratio) allow coverage of larger areas, facilitate drainage
• Sheet grafts - used for cosmetically important areas (face, hands, joints)
• Donor site heals in 10-14 days and can be reharvested

• Allograft (cadaveric skin) - temporary biological dressing; lasts 2-3 weeks before rejection; reduces evaporative losses, promotes granulation
• Xenograft (pig skin/porcine) - temporary, cheaper; lasts ~1 week
• Amnion (amniotic membrane) - biological dressing, antibacterial properties
• Biobrane - biosynthetic (nylon mesh + silicone + porcine collagen); for superficial partial-thickness burns
• Integra (acellular dermal matrix) - bilayer matrix providing neodermis; ultrathin epidermal autograft placed 2-3 weeks later; used for large full-thickness burns
• AlloDerm - acellular human dermal matrix

• Keratinocytes cultured from patient's own skin (takes 2-3 weeks)
• Useful for >50-70% TBSA where donor sites are scarce
• Fragile grafts, high failure rate, but life-saving in massive burns

11. ESCHAROTOMY & FASCIOTOMY

Escharotomy

• Indicated when full-thickness circumferential burn threatens vascular supply to limb or restricts chest wall expansion
• Limb escharotomy: longitudinal incisions along medial and lateral aspects of the extremity, through the eschar only (not fascia)
• Chest escharotomy: bilateral anterior axillary line incisions connected by submammary transverse incision (improves tidal volume and ventilation)
• Monitoring: compartment pressures, clinical exam (pulses, Doppler), capillary refill

Fasciotomy

• Required when underlying muscle compartment syndrome develops (electrical burns, circumferential deep burns with edema)
• Must release ALL compartments (e.g., both volar and dorsal forearm; all 4 compartments of the leg)

12. NUTRITION IN BURNS

• Metabolic rate may increase up to 200% of baseline
• Leads to: protein catabolism, muscle wasting, immune suppression, impaired wound healing

Feeding

• Early enteral feeding (within first few hours): reduces lean body mass loss, blunts hypermetabolic response, improves protein metabolism, shorter ICU stay, fewer wound infections
• Target >20% TBSA patients for early enteral feeding
• Nasojejunal feeding if gastric feeds not tolerated
• Enteral feeds NOT held for OR trips in intubated patients

Caloric Calculations

• Currier Formula (recommended for burns <40% TBSA): 25 kcal/kg/day + 40 kcal/%TBSA/day
• Harris-Benedict equation × 2 (for burns): less accurate for moderate burns
• Indirect calorimetry: no proven benefit over predictive equations in burn patients

Pharmacologic Modulation of Hypermetabolism

• Propranolol (β-blocker): decreases heart rate, resting energy expenditure, protein catabolism - extensively studied in pediatric burns; some use in adults with caution (risk of hypotension/bradycardia)
• Oxandrolone (anabolic steroid): improves lean body mass, bone density, hepatic protein synthesis; decreased length of stay; associated with decreased mortality in large burns; rise in transaminases seen
• Insulin/tight glycemic control: reduces hyperglycemia-associated morbidity; target blood glucose 80-110 mg/dL (with monitoring)
• Glutamine supplementation: decreases infectious complications, possible T-cell modulation effect; ongoing RCT studying mortality impact

Micronutrients

• Antioxidant vitamins (vitamins C and E) and trace minerals (selenium, zinc, copper) optimize wound healing, immune function, and combat oxidative stress

13. COMPLICATIONS IN BURN CARE

Infection & Sepsis

• Leading cause of morbidity and mortality in burn patients
• Disruption of skin barrier + immune dysfunction = high infection risk
• Burn wound infection vs. bacteremia vs. sepsis must be distinguished
• ABA sepsis criteria in burns (different from standard Sepsis-3 criteria):
  • Temperature >39°C or <36.5°C
  • Heart rate >110/min
  • Respiratory rate >25/min or minute ventilation >12 L/min
  • Thrombocytopenia (<100,000/µL) after day 3
  • Hyperglycemia (>200 mg/dL in non-diabetics)
  • Inability to continue enteral feeds >24 hours
• Most common organisms: Staph. aureus, Pseudomonas aeruginosa, Klebsiella, Candida
• MRSA and multidrug-resistant Gram-negatives increasingly common
• Wound biopsy (quantitative) >10^5 organisms/gram tissue = wound infection

Pulmonary Complications

• Pneumonia: most common infectious complication in intubated burn patients
• ARDS: significant mortality contributor
• Respiratory failure: from inhalation injury, ARDS, sepsis

Renal Complications

• Acute Kidney Injury (AKI): from hypovolemia, myoglobinuria (rhabdomyolysis - especially electrical burns), sepsis
• Myoglobinuria management: aggressive IV fluids to maintain UO 1 mL/kg/h until urine clears; consider bicarbonate urinary alkalinization; mannitol as osmotic diuretic

Abdominal Compartment Syndrome

• From aggressive fluid resuscitation ("fluid creep")
• Presents with rising airway pressures, decreasing urine output, tense abdomen
• Bladder pressure >20 mmHg with organ dysfunction = abdominal compartment syndrome
• May require decompressive laparotomy

Ileus & GI Complications

• Curling's ulcer: acute stress ulcer in burn patients (historically common, now reduced with H2-blockers/PPIs and early feeding)
• Ileus: common in acute phase; early enteral feeding helps
• Acalculous cholecystitis in critically ill burn patients

Heterotopic Ossification (HO)

• Ectopic bone formation in periarticular soft tissues
• Particularly at elbow in burn patients
• Risk factors: prolonged immobilization, large burns
• Managed with: range-of-motion exercises, NSAIDs (prophylaxis), surgical excision after maturation (12-18 months)

14. HYPERTROPHIC SCARS AND CONTRACTURES

Hypertrophic Scars

• Raised, red, indurated scars confined within the wound margins (differ from keloids which extend beyond margins)
• Occur in deep partial-thickness and full-thickness burns, especially when healing takes >21 days
• Risk factors: dark skin, burn across joints or flexural surfaces, young age, prolonged inflammation

Scar Management

• Compression therapy: custom pressure garments worn 23 hours/day for 12-24 months; reduces scar hypertrophy by decreasing vascularity and collagen production
• Silicone gel sheets: applied to scars; mechanism unclear (hydration, pressure); effective for hypertrophic scars
• Intralesional corticosteroid injection (triamcinolone): for localized hypertrophic scars
• Laser therapy: pulsed dye laser, fractional CO2 laser - improving scars and itch
• Surgical release: for disabling contractures

Contractures

• Occur across joints from scar contraction
• Prevention: early splinting and positioning (antideformity position), range-of-motion exercises
• Antideformity positions:
  • Neck: extension (not flexion)
  • Shoulder: 90° abduction
  • Elbow: extension
  • Hand: intrinsic-plus position (wrist neutral-to-slight extension, MCP 70-90° flexion, IP joints extended, thumb abducted)
  • Hip: extension, neutral rotation
  • Knee: extension
  • Ankle: 90° dorsiflexion

15. SPECIAL BURNS

Electrical Burns

• Low voltage (<1000 V): household; local tissue injury
• High voltage (>1000 V): industrial; entry/exit wounds, "iceberg" deep tissue injury (more extensive than surface appearance)
• Lightning: flashover phenomenon may limit deep tissue injury; direct effects cause cardiac arrest, respiratory arrest
• Complications: cardiac arrhythmias (ECG monitoring required for high-voltage), rhabdomyolysis, AKI, cataracts, peripheral neuropathy
• Management: aggressive fluid resuscitation (higher volumes needed than Parkland formula), urine output 1 mL/kg/h until myoglobinuria clears, fasciotomy often needed

Chemical Burns

• Duration and concentration determine depth
• Alkali burns (e.g., NaOH, cement): liquefactive necrosis, tend to be deeper, penetrate further
• Acid burns (e.g., HF, sulfuric acid): coagulative necrosis; self-limiting to some extent
• Hydrofluoric acid: binds calcium → hypocalcemia (life-threatening); treat with calcium gluconate (topical gel or intralesional injection)
• Management: copious irrigation with water (remove clothing immediately); do NOT use neutralizing agents (exothermic reaction)
• pH-guided irrigation until wound pH normalizes

Radiation Burns

• Acute radiation syndrome
• Management: bone marrow transplantation for marrow failure; wound management similar to thermal burns

16. REHABILITATION

• Early mobilization is key - begin as soon as hemodynamically stable
• Splinting in antideformity positions from day 1
• Physical and occupational therapy throughout hospitalization and after discharge
• Psychological support: PTSD, depression, body image issues are common
• The National Institute of Disability and Rehabilitation Research (NIDRR) funds burn model systems tracking long-term outcomes since 1993

17. PSYCHOLOGICAL RECOVERY

• Burn injuries are traumatic events with significant psychological sequelae
• PTSD rate is high in burn survivors
• Depression and anxiety are common
• Sleep disturbance, itch (pruritus - one of most distressing long-term symptoms), and chronic pain affect quality of life
• Multidisciplinary approach: psychology, social work, peer support groups
• Return to work and school is a key outcome measure (ABA burn model systems)

18. BURN DISASTERS / MASS CASUALTY

• Mass casualty burn events stretch healthcare systems
• General surgeons may be first responders - must be comfortable with basic burn care
• Regional burn center surge capacity is limited
• Expectant triage (usually withheld in routine trauma) may be used for burns with near-unsurvivable injuries in a mass casualty context
• ABA provides mass casualty burn guidelines

19. SUMMARY TABLE: KEY FORMULAS & BENCHMARKS