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Electrical injuries
From WikEM
Contents
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
- Low-Voltage <1000V
- High-Voltage >1000V - typically seen in industrial settings or transmission line injuries
- Associated with electrical burns
- Lightning Strike
- Electric Arc
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
- Can lead to compartment syndrome
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
- Forceful muscle contractions can cause fracture and joint dislocations (especially shoulder)
- May occur with voltages as low as 120V
- Compartment Syndrome
- Usually associated with high-voltage injuries
- May occur even with 120V shocks if contact is sustained for longer than few seconds
- Patient experiences ongoing muscle pain with movement
- Need for fasciotomy predicted by:
- Myoglobinuria
- Burns >20% BSA
- Full-thickness burn >12% BSA
- Rhabdomyolysis
- Associated with:
- Contact with >1000V
- Prehospital cardiac arrest
- Crush injury
- Compartment syndrome
- Full-thickness skin burns
- Associated with:
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
- Burn
- First degree
- Second degree
- Third degree
- Fourth degree
- Smoke inhalation injury (airway compromise)
- Chemical injury
- Acrolein
- Hydrochloric acid
- Tuolene diisocyanate
- Nitrogen dioxide
- Systemic chemical injury
- Electrical injury
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
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
- ↑ 1.0 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.
- ↑ Koumbourlis AC. Electrical injuries. Crit Care Med. 2002 Nov;30(11 Suppl):S424-30.
- ↑ Brandt CP, Yowler CJ, Fratianne RB. MetroHealth Medical Center Burn ICU Handbook (Not a policy manual), Cleveland, OH.
- ↑ Rai J, Jeschke MG, Barrow RE, Herndon DN. Electrical Injuries: A 30-Year Review. J Trauma Acute Care Surg. 1999;46(5):933-936.
