Electrical injuries

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Background

  • Tissue damage occurs via electrical energy (becomes thermal energy once it enters the body) and mechanical injury from trauma
    • Skin, bone, tendon all have very high resistance
    • Muscle, nerves, vasculature have lower resistance, more often damaged
  • The primary determinant of injury is the amount of current flowing through the body, which depends on:
    • Voltage
    • Amperage
    • Resistance
    • Type of current (DC or AC)
    • Current pathway
    • Duration of contact

Electrical Injury Types

  1. Low-Voltage <1000V
  2. High-Voltage >1000V - typically seen in industrial settings or transmission line injuries
    • Associated with electrical burns
  3. Lightning Strike
  4. Electric Arc
    • Associated with high voltage sources
    • Ionized particles with temperature 3000 °C–20,000 C[1]
    • Can jump 2-3cm per 1000V[1]
    • May radiate enough heat to burn persons 10ft or more away from the arc
    • Blast force may result in trauma

DC vs AC

Direct current (DC) injuries typically due to lightning while alternating current (AC) are household injuries

DC

  • Direct current most often demonstrates flow-over phenomenon
  • Lightening can reach 1-5 million volts, but current flows over the body and exits to the ground
  • May result in little tissue damage and cardiac dysrrhythmias are still of great concern

AC

  • Current arcs onto body, envelops surface of body, then arcs to lower electromotive potential (ground)
  • With alternative cycle of the current there is contraction and release of muscle preventing full release from source
  • Current flows through body tissues

Clinical Features

Immediate Effects

Cardiac Dysrhythmias

  • Fatalities due to asystole or V-fib usually occur prior to arrival
    • Most common dysrrhythmia at presentation is A-fib (V-fib is more common, but patients are dead PTA)
    • Asymptomatic patients with normal ECGs do not develop later dysrhythmias after <1000V injuries

Cardiovascular Injury

  • Contraction band necrosis[2]
  • Medial necrosis of large vessels
    • Aneurysm formation
  • Coagulation necrosis of small vessels

CNS Injury

  • Occurs in 50% of patients with high-voltage injuries
  • Brain injury ranges from transient LOC to CVA to respiratory arrest
  • High voltage injuries involving head are frequently associated with coma and persistent vegetative state

Orthopedic Injury

Ocular Injury

  • Cataract formation has been described weeks to years after electrical injury
    • Document presence or absence of cataracts following all electrical injuries

Auditory Injury

  • May be damaged by current or hemorrhage
  • Check hearing in all patients

Cutaneous Burns

  • Often seen at electrical contact areas
    • Seriously injured patients often have burns on either arm or skull + feet
  • Most patients with burns from electrical injury require admission and care by burn specialist

GI Injury

  • Suspect in patients with:
    • Electrical burns of abdominal wall
    • History of a fall, nearby explosion, or other mechanical trauma

Pediatric Considerations

  • In general, evaluate as for the adult, looking for multi-system involvement
  • Perform an ECG in all patients, regardless of voltage
  • An oral commissure burn (from chewing on power cord) will create significant edema and necrosis.
    • The child may need Plastic Surgery or Head and Neck Surgery consultation to avoid microstomia.
    • 1-2 weeks after the burn, the eschar may fall off, exposing the labial artery and causing significant hemorrhage
      • Provide clear and thorough precautionary advice including first aid for bleeding (pinch buccal mucosa against outside of cheek until arrival to hospital)

Differential Diagnosis

Burns

Evaluation

Workup

  • 12-lead ECG
  • CBC
  • CMP
  • Lactate
  • Troponin
  • CK
  • Urinalysis and urine myoglobin

Diagnosis

  • Typically a clinical diagnosis

Management

  • Usual trauma evaluation and resuscitation applies
  • Use Parkland formula as starting point for fluid resuscitation
    • Fluids in first 24 hrs = TBSA burned(%) x Wt(kg) x 4ml; Give 1/2 in first 8 hours, then give other 1/2 over next 16 hrs
  • Treat rhabdomyolysis and compartment syndrome in usual manner
    • If RBCs and/or myoglobin in UA, urine should be alkalinized at minimum of 2 cc/kg/hr until pigments eliminated[3]
    • Mannitol should be given early to prevent renal tubular damage
    • High voltage injuries to the hand frequently require carpal tunnel decompression as soon as patient is stable for OR

Disposition

Discharge

  • Asymptomatic patients with normal ECG on presentation after a low-voltage electrical injury[4]

Admit

  • All patients with high-voltage injuries (even if asymptomatic)
  • Patients with low-voltage injury if symptomatic (e.g. LOC, severe burns, ECG changes, ↑ CK)
  • Abnormal ECG or observed dysrhythmia
  • Cardiac biomarkers positive
  • Persistent chest pain, paresthesias, or hypoxia
  • Cardiac arrest
  • Documented LOC
  • History of significant cardiac disease or CAD risk factors

See Also

External Links

References

  1. 1.0 1.1 Kym D, Seo DK, Hur GY, Lee JW. Epidemiology of electrical injury: Differences between low- and high-voltage electrical injuries during a 7-year study period in South Korea. Scand J Surg. 2015 Jun;104(2):108-14.
  2. Koumbourlis AC. Electrical injuries. Crit Care Med. 2002 Nov;30(11 Suppl):S424-30.
  3. Brandt CP, Yowler CJ, Fratianne RB. MetroHealth Medical Center Burn ICU Handbook (Not a policy manual), Cleveland, OH.
  4. Rai J, Jeschke MG, Barrow RE, Herndon DN. Electrical Injuries: A 30-Year Review. J Trauma Acute Care Surg. 1999;46(5):933-936.