Electrical injury
| Magnitude of current rather than voltage suggests severity of burn | |
|---|---|
| Etiology | - low voltage (<600V) → contact burn - high voltage (>1000V) -> entrance & exit wound -> may require fasciotomy -> side flash = nearby lightning strike -> superficial burns, entry & exit burns +/- respiratory arrest - direct lightning strike -> often fatal |
| Epidemiology | Bimodal - curious toddlers (<6y) and young adults |
| Clinical presentation | A: intra-oral burns (especially children - chewing cables) B: respiratory arrest (tetany of diaphragm/intercostal muscles or pulmonary oedema); inhalational injuries (fire or high voltage injuries) C: arrhythmias - asystole (with direct current) or VF/VT (with AC) - due to focal necrosis of myocardium D: seizures, memory impairment E: cutaneous burns - disproportionate to underlying damage; rhabdo; compartment syndrome Corneal burns (especially in UV radiation, or arcing current) |
| Diagnostic investigations | ECG Creatine kinase |
| Management | Severe burns - treat as per major trauma/burns Arrest - standard cardiac arrest principles (hypoxia, hyperkalaemia, hypovolaemia may move higher up reversible causes). Still shock them. More electricity!! Rhabdomyolysis Fluid resuscitation - not quite Parkland formula |
Low magnitude injury
- Main risks: Malignant dysrhythmia
- If baseline ECG normal, ECG monitoring unlikely to yield much
Risk factors for more severe injury
- magnitude of current (not voltage)
- resistance of tissues in current pathway
- duration of exposure (correlates with thermal injury as well)
- AC vs DC
- AC → muscle tetany
- DC → single violent muscle contraction; more likely to produce asystole
- Current pathway through body