Electrical injuries: Difference between revisions
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**All pts with high-voltage injuries (even if asymptomatic) | **All pts with high-voltage injuries (even if asymptomatic) | ||
**Pts w/ low-voltage injury if symptomatic (e.g. LOC, severe burns, EKG changes, ↑ CK) | **Pts w/ low-voltage injury if symptomatic (e.g. LOC, severe burns, EKG changes, ↑ CK) | ||
**Abnormal EKG or observed dysrhythmia | |||
**Cardiac biomarkers positive | |||
**Persistent CP or hypoxia | |||
**Cardiac arrest | |||
**Documented LOC | |||
**Hx of significant cardiac disease or CAD risk factors | |||
==See Also== | ==See Also== |
Revision as of 19:23, 16 August 2015
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 pts are dead PTA)
- Asymptomatic pts w/ 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 pts w/ 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 a/w high-voltage injuries
- May occur even with 120V shocks if contact is sustained for longer than few seconds
- Pt 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 pts
Cutaneous Burns
- Often seen at electrical contact areas
- Seriously injured pts often have burns on either arm or skull + feet
- Most pts w/ burns from electrical injury require admission and care by burn specialist
GI Injury
- Suspect in pts with:
- Electrical burns of abdominal wall
- History of a fall, nearby explosion, or other mechanical trauma
- Labial artery bleeding may be delayed well after injury, warranting admission (typically peds pts who chew power cords)
Workup
- 12-lead EKG
- CBC
- CMP
- Lactate
- Troponin
- CK
- UA and urine myoglobin
Treatment
- 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 rhabdo and compartment syndrome in usual manner
Disposition
- Discharge
- Asymptomatic pts w/ normal ECG on presentation after a low-voltage electrical injury
- Admit
- All pts with high-voltage injuries (even if asymptomatic)
- Pts w/ low-voltage injury if symptomatic (e.g. LOC, severe burns, EKG changes, ↑ CK)
- Abnormal EKG or observed dysrhythmia
- Cardiac biomarkers positive
- Persistent CP or hypoxia
- Cardiac arrest
- Documented LOC
- Hx of significant cardiac disease or CAD risk factors
See Also
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.