Electrical injuries

(Redirected from Electrocution)

Background

  • Tissue damage occurs via electrical energy (becomes thermal energy once it enters the body) and mechanical injury from trauma
    • Fat, bone, tendon, dry skin 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
  • Lightning can reach 1-5 million volts, but current flows over the body and exits to the ground
  • May result in little tissue damage but 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

Superficial second degree burn from lightning injury.
Lichtenberg figure from lightning injury.
Patterned charring along the contact points of a metallic locket due to lightning strike.
Second-degree burn after a high tension line electrical injury.

Immediate Effects

Cardiac Dysrhythmias

  • Fatalities due to asystole or V-fib usually occur prior to arrival
    • Most common dysrhythmia 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
      • For uncomplicated electrical injuries if normal EKG then routine ECG monitoring and cardiac biomarkers unnecessary[2].

Cardiovascular Injury

CNS Injury

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
  • Lichtenberg figures (not true burns) are pathognomonic for lightning strike

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
    • Urine myoglobin is poorly sensitive/specific, and most patients with rhabdomyolis will have grossly discolored urine[4]

Diagnosis

  • Typically a clinical diagnosis

Burn Thickness Chart[5]

Thickness Deepest Skin Structure Involved Pain & Sensation Appearance Expected Course Image
Superficial (first-degree)
  • Epidermis
  • Painful
  • Dry, erythema (no blisters)
  • Blanching (intact cap refill)
  • Heals without scarring, 5-10 days

Sunburn.jpg

Superficial Partial (second-degree)
  • Superficial dermis (papillary region)
  • Painful
  • Wet, pale pink, blisters
  • Blanching (intact cap refill)
  • Heals without scarring, <3 weeks

Hand2ndburn.jpg Scaldburn.jpg

Deep Partial (second-degree)
  • Deep dermis (reticular region)
  • Decreased sensation
  • Pale white-yellow, blisters
  • Does not blanch (absent cap refill)
  • Heals in 3-8 weeks
  • Likely to scar if healing >3 weeks
  • May require skin-graft if does not heal within 3 weeks

Major-2nd-degree-burn.jpg

Full (third-degree)
  • Hypodermis (subcutaneous tissue)
  • Decreased sensation
  • White, leathery
  • Does not blanch (absent cap refill)
  • Heals by contracture, >8 weeks
  • Almost always requires skin grafting

8-day-old-3rd-degree-burn.jpg

Fourth-degree
  • Underlying fat, muscle and bone
  • Decreased sensation
  • Black; charred with eschar
  • Does not blanch (absent cap refill)
  • Does not heal
  • Frequently requires amputation

Ожог кисть.jpg

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
    • Parkland formula frequently underestimates fluid requirements in electrical burns[6] because internal injuries are usually more significant than external burns
    • In healthy individuals start continuous fluids at 300-500 mL/hr and titrate to urine output of 100 mL/hr[7]
  • 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[8]
    • Mannitol should be given early to prevent renal tubular damage but patient must remain adequately fluid resuscitated
    • 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[9]

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
  • 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. Pilecky D, Vamos M, Bogyi P, et al. Risk of cardiac arrhythmias after electrical accident: a single-center study of 480 patients. Clin Res Cardiol. 2019;108(8):901–908. doi:10.1007/s00392-019-01420-2 Abstract at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6652167/
  3. Koumbourlis AC. Electrical injuries. Crit Care Med. 2002 Nov;30(11 Suppl):S424-30.
  4. https://emergencymedicinecases.com/electrical-injuries/
  5. Haines E, et al. Optimizing emergency management to reduce morbidity and mortality in pediatric burn patients. Pediatric Emergency Medicine Practice. 12(5):1-23. EB Medicine.
  6. https://emergencymedicinecases.com/electrical-injuries/
  7. https://emergencymedicinecases.com/electrical-injuries/
  8. Brandt CP, Yowler CJ, Fratianne RB. MetroHealth Medical Center Burn ICU Handbook (Not a policy manual), Cleveland, OH.
  9. Rai J, Jeschke MG, Barrow RE, Herndon DN. Electrical Injuries: A 30-Year Review. J Trauma Acute Care Surg. 1999;46(5):933-936.