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Electrical Injury
Aka: Electrical Injury, Electrical Burn, High Voltage Electricity, Electricity Shock, High Voltage Injury, Low Voltage Injury, Electrocution
- See Also
- Burn Injury
- Burn Management
- Lightning Injury
- Trauma Evaluation
- Epidemiology
- Electrical injuries cause 1000 deaths in U.S. per year
- Pathophysiology
- Electricity travels a path until it meets resistance
- Skin offers resistance to low current, but with enough current a burn hole through the skin is established
- Burn allows current to pass bypass intact skin via Electrolytes into nerves, muscles, vascular structures
- Skin resistance is lowered by a factor of 100 when it is wet (i.e. wet skin is a much reduced barrier to Electrical Injury)
- Carbonized tissue resists continued current
- Electrical Injury results in thermal Burn Injury
- Most common injury sites
- Deep Skin Injury
- Neurologic injury
- Spinal cord injury (e.g. motor or sensory deficit)
- CNS injury (e.g. Altered Level of Consciousness)
- Eye Injury
- Cataracts
- Corneal burn
- Retinal Detachment
- Cardiovascular injury
- Cardiac Arrest
- Arrhythmia
- Types
- Alternating Current (AC): Low voltage home injury
- AC is 3 times more dangerous than DC at same voltage
- Typical AC current is at 60 Hz and may result in muscle Tetany
- Patient involuntarily grips source
- Prolongs duration of contact and increases injury
- Diaphragmatic paralysis (apnea) may occur even with low voltage (e.g. welding)
- Alternating current may cause Ventricular Fibrillation
- Direct Current (DC): High voltage Occupational Injury
- May throw patient from jolt of energy
- May result in blunt injury in addition to burns
- Low voltage DC current may cause brief Asystole followed by sinus rhythm (similar to Defibrillation)
- Voltage
- Amperage (current through tissue) is most related to tissue injury
- However, as amperage is typically unknown, voltage is used as a surrogate
- Low voltage Electrical Injury: <1000 Volts
- House power outlet: 110 to 240 volts
- Serious injury and morbidity increases significantly over 600 volts
- High voltage Electrical Injury: >1000 Volts
- Power Lines: 7200 volts
- High voltage power lines: 155,000 to 765,000 volts
- At high voltage, differences between AC and DC current becomes less important
- Lightning Injury: 30 million to 1 billion volts
- Arc Injury (High Voltage Injury)
- Occurs when patient is too close to a high voltage line and electricity diverts from line to body
- Patient becomes part of arc of current between 2 objects
- Most serious Electrical Injury
- Severe blunt Trauma may result
- Temperature may exceed 2500 C (4532 F)
- Risk Factors: Lethal Electrical Injury
- Wet skin exposure
- Tetany
- Voltage >600-1000
- Electrical current that passes across the head
- Transthoracic electrical pathway (Arm-to-arm transmission, Arm to leg transmission, Chest direct contact)
- Does not increase risk of delayed Arrhythmia if alive at Emergency Department presentation
- Bailey (2007) Emerg Med J 24(5):348-52 [PubMed]
- History
- Type of electrical exposure (e.g. house power outlet, battery or power line)
- Attempt to estimate voltage (see above)
- Direct current or alternating current
- Duration of electrical current exposure (e.g. may occur with Tetany)
- Modifying factors (e.g. wet skin that increases electrical conductivity)
- High risk distribution of injuries (trans-thoracic contact points to electrical source)
- Arm-to-arm transmission
- Arm to leg transmission
- Chest direct contact
- Secondary Traumatic injuries (e.g. patient thrown)
- Arrhythmias noted on prehospital evaluation
- Exam
- See Trauma Primary Survey
- See Trauma Secondary Survey
- Estimate the percentage of total body surface area burn
- Precaution: Deep tissue damage may be extensive despite minimal surface skin changes
- Evaluate and monitor extremities with Electrical Injury for Compartment Syndrome
- Diminished pulse
- Increased pain on passive extremity movement
- Pallor
- Increased compartment pressures
- Consider pathway of current
- Electrical current that passes across the head or chest is high risk for serious morbidity and mortality
- Labs
- First-line labs
- Complete Blood Count (CBC)
- Basic metabolic panel (Chem8)
- Creatine Kinase (CK)
- Urinalysis
- Labs with lower efficacy in Electrical Burns
- Cardiac Enzymes (Troponin)
- Poor correlation with cardiac damage and LV dysfunction in Electrical Burns
- CK-MB is falsely increased in Electrical Burns
- Diagnostics
- Electrocardiogram
- Evaluate for Arrhythmia
- Management: General
- Resuscitation and Stabilization should follow ACLS and Trauma protocols
- See ABC Management
- See Trauma Evaluation
- Manage Arrhythmias via ACLS protocol
- Electrical (Thousands of volts) and lightning (Millions of volts) injuries are treated differently
- See Lightning Injury
- Specific Electrical Burn management
- See Burn Management
- Parkland formula for fluid Resuscitation typically underestimates requirements in Electrical Burns
- Rhabdomyolysis management if elevated Creatine Phosphokinase (CPK)
- Maintain Urine Output 200-300 ml/hour
- Evaluate for Compartment Syndrome
- Deep muscle layers adjacent to bone are most susceptible (as bone has higher resistance to electricity)
- High risk for amputation, especially upper extremities (28 to 45% risk)
- Early exploration and decompression in all suspected cases
- Mouth burns in young children who may have chewed on live wire
- May present with injury at lateral commissure at mouth
- Close interval follow-up with oral maxillofacial surgery or plastic surgery
- Complications
- Functional and disfiguring complications
- Delayed labial artery bleeding at 5-14 days after Burn Injury
- Other measures
- Update tetanus Vaccine
- Management: Disposition
- Burn center transfer indications
- High voltage extremity injury (esp. if concerns of Compartment Syndrome)
- Indications for admission with continuous cardiac monitoring (same criteria in children and adults)
- High Voltage Injury
- Admit all High Voltage Injury patients (and monitor with telemetry) for at least 12 to 24 hours
- Low Voltage Injury Observation Indications (may also observe on telemetry for 6 hours, and one ekg at discharge)
- Loss of consciousness
- Abnormal EKG (at any time in their evaluation following Electrical Injury)
- Extensive Soft Tissue Injury or intractable pain
- Indications for outpatient management (all criteria)
- Low-voltage exposure AND
- Normal exam AND
- Normal laboratory examination (No Myoglobinuria, normal CK, normal Renal Function) AND
- Electrocardiogram (EKG) normal
- Complications
- Rhabdomyolysis
- Cardiac Injury including Arrhythmia (e.g. Ventricular Fibrillation, Asystole, Atrial Fibrillation)
- Compartment Syndrome (and risk of Extremity Amputation)
- Secondary injury (from being thrown from DC electrical source)
- Neurologic Injury (altered level of consciousness, Seizure disorders)
- References
- Swaminathan and Patel in Herbert (2019) EM:Rap 19(11):1-3
- Walrath, Wood, Della-Giustina (2019) Crit Dec Emerg Med 33(6): 3-11
- Martinez (2000) South Med J 93:1165-8 [PubMed]