Burn

Coagulative necrosis of tissue result from thermal (heat/cold), electrochemical or radiation injury

• Heat
• Cold
• Electrical burns
• Chemical burns
• Radiation burns

Assesment of burns

1. Extent (size)
   • % body area: Wallace's rule of 9s
   • Hand = 1%
2. Depth
   • Superficial - epidermis (painful: erythema, no blistering, heal within 2-5 days)
   • Partial thickness - epidermis and variable amounts of dermis (painful: erythema, blistering)
   • Full thickness - all of dermis (painless, white/waxy)

Criteria for referral to Burns unit:

1. Patient
   • Extremes of age
2. Burn
   • Size >15% (10% paediatric)
   • Location: hands/feet/perineum
   • Circumferential burns (requiring escharotomy to prevent ischaemia and necrosis)
   • Electrical burns (risk of rhabdomyolisis)

Management

1. Airway/Breathing
   • Resp distress / high flow oxygen
   • Early intubation and support
2. Circulation
   • Monitor fluid therapy

     ATLS guideline: 2-4mls/kg/%burn in 24 hours: give half in first 8 hours, half over remaining 16 hours (Modified Parkland Formula)

     Mount vernon: Weight x%burn/2

   • Central venous line
   • Urinary catheter
3. Disability
   • Assess wound size
   • Cover wounds + tetanus prophylaxis
   • Renal support
   • Analgesia
4. Exposure
   • Warm
   • Stress ulcer prophylaxis
5. Surgery - constricting circumferential thoracic eschars
6. Nutritional supplementation commenced early
7. Priority areas for skin grafting - eyelids (prevents ectropion), face, hands, joint flexures

Complications

1. Respiratory: fire in confined space, soot in mouth/sputum, hoarse voice, >10% serum carboxyhaemoglobin
   • Thermal injury to nose / oropharynx with upper airways oedema
   • Smoke inhalation can lead to hypoxia and pulmonary oedema from ARDS
   • Toxic gases: carbon monoxide (250 more affinity for Hb), cyanide, sulphur, nitrogen
2. Shock
   • Plasma protein loss (loss of skin cover)
3. Renal failure
   • Hypovolaemia from plasma protein loss reduces renal perfusion + ATN
   • Myoglobin (from muscle) produces rhabdomyolysis and results in ATN
4. Electrolyte disturbance
   • Hypo/hypernatramia
   • Hypo/hyperkalaemia
5. Hypothermia
   • Loss of skin cover
6. SIRS / Sepsis
7. Gastric ulcers
   • Curling's ulcers (cf Cushing's ulcers) as part of stress response
8. Coagulopathy
   • Due to DIC