Burns and soft-tissue emergencies
Inhalational, electrical and chemical burns
Overview and approach
These mechanisms can cause serious internal injury disproportionate to skin findings.
- Special burns from your objectives: respiratory (inhalation), electrical and chemical1,2,3.
- How smoke injures: heat mainly burns the mouth, nose and upper airway, causing swelling. Water-soluble gases (ammonia, chlorine, sulphur oxides) form acids or alkalis in the moist upper airway and add to the oedema, while fat-soluble products (burning plastics, nitrogen oxides) reach the small airways and cause pneumonitis. Lung injury can appear 24-48 hours after the fire7.
- Inside the airway: mucosal burns, bronchospasm, heavy secretions, paralysed cilia, loss of surfactant and plugging by debris, plus a systemic inflammatory response. Inhalation injury markedly increases fluid needs6.
- Carbon monoxide: binds haemoglobin over 200 times more avidly than oxygen and also stops the remaining haemoglobin releasing oxygen to tissues (left shift), so tissue hypoxia is worse than the saturation suggests. Severe poisoning can produce a cherry-pink, apnoeic patient6,8.
- How electricity injures: harm depends on current, duration and the path through the body. Alternating current causes tetanic muscle spasm, so the person cannot let go and contact is prolonged; chest wall spasm can cause asphyxia. High-voltage current more often stops the brainstem respiratory centre and causes extensive deep burns7.
- Acid vs alkali: acids cause coagulative necrosis and are usually painful at once. Alkalis (bleach, cleaning products, wet cement) cause liquefactive necrosis, penetrate deeper, and the pain is often delayed, so first aid starts late and damage continues6.
- Hydrofluoric acid penetrates deeply and binds calcium, so even a small burn can cause dangerous systemic toxicity6.
Types of electrical injury6,7.
| Type | Source | Typical pattern | Main dangers |
|---|---|---|---|
| Low voltage | Household or workplace mains | Small, deep entry and exit wounds, often on the hands | Arrhythmia if current crosses the heart |
| High voltage | 1000 V or more (power lines) | Extensive deep tissue and muscle destruction under modest skin wounds | Rhabdomyolysis, kidney failure, compartment syndrome, cardiac arrest |
| Lightning | Very high voltage, brief direct current | Variable; side flash from a nearby object is commoner than a direct strike | Direct strike has high mortality (cardiac and respiratory arrest) |
Assessment and clinical features
Smoke/enclosed space, voice/airway symptoms, exposure agent, electrical path and loss of consciousness.
- Inhalation: suspect with soot, singed hairs, hoarseness, stridor, carbonaceous sputum, facial or neck burns, enclosed-space exposure1,2,3.
- Electrical: voltage, duration, entry and exit wounds, loss of consciousness, arrhythmia, muscle injury1,4.
- Chemical: agent (acid, alkali, hydrofluoric acid), concentration, duration, eye involvement.
Differentials and investigations
Monitored airway assessment, selected CO/toxicology/electrical-injury testing; involve poison/burns services.
- Inhalation: carboxyhaemoglobin and lactate; cyanide toxicity in enclosed-space fires; bronchoscopy as directed by senior staff.
- High-voltage or significant electrical injury: 12-lead ECG, cardiac monitoring, CK and urine myoglobin1,4.
- Hydrofluoric acid: ECG and calcium, magnesium and potassium monitoring (QT prolongation)5.
- Low-voltage injury with a normal ECG and no loss of consciousness does not usually need admission for cardiac monitoring; significant injuries need continuous monitoring6.
- In high-voltage injury, dark urine from haemoglobin or myoglobin is common. Standard burn fluid formulas underestimate needs because most of the damage is hidden beneath the skin6.
Management and follow-up
Resuscitation and mechanism-specific decontamination/treatment; avoid exposing staff and use appropriate protection.
- Inhalation: 100% oxygen, early intubation for distress or progressive airway oedema1,2,3.
- Electrical: make safe first; cardiac monitoring; fluids for rhabdomyolysis; assess compartments (see Acute compartment syndrome).
- Chemical: remove clothing and irrigate copiously with water (hydrofluoric acid: at least 30 minutes, then calcium gluconate gel)1,5. Contact Poisons Information (13 11 26 in Australia) and follow local protocols.
- All require burns-service discussion. Electrical, chemical and airway burns all meet burns-unit referral criteria regardless of size6.
Red flags and clinical pearls
Airway deterioration, arrhythmia and toxic exposure need early expert help. Normal pulse oximetry does not exclude carbon monoxide poisoning.
- Airway oedema can progress rapidly: intubate early rather than late.
- Small entry wounds can hide deep muscle injury. High-voltage limb injuries may need fasciotomy6.
- Turn off the power before touching an electrical injury victim, and protect rescuers from chemical contamination6.
- Alkali burns may hurt little at first: do not let a lack of pain shorten irrigation6.
References
- NSW ACI ECAT: Adult burns
- Vanderbilt: Adult inhalation injury protocol (2026)
- RCH: Burns - acute management
- IAEM: Management of thermal, chemical and electrical burns in the ED
- StatPearls: Hydrofluoric acid burns
- Burnand KG, Black J, Corbett SA, Thomas WEG, editors. Browse's Introduction to the Investigation and Management of Surgical Disease. Boca Raton: CRC Press; 2010. Chapter 5, The skin and subcutaneous tissues.
- Kumar V, Abbas AK, Aster JC, editors. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Philadelphia: Elsevier Saunders; 2015. Chapter 9, Environmental and nutritional diseases.
- West JB. Pulmonary Pathophysiology: The Essentials. 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2013. Chapter 7, Diseases caused by inhaled particles.
Last updated from Sen’s notes on 22 October 2026.