Transcript Electrical Injuries

Electrical Injuries
CHRIS PONDER
PGY 3
No Disclosures
Objectives

Epidemiology

Physics

Classification of Injury
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Mechanisms of Injury
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Electrical Weapons
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Management
Epidemiology
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Electrical burns account for 3-4% of all burns
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> 3000 admissions to burn units annually
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Burns in Children are accidental
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< 6 are electoral cords or outlets
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Oral burns are common
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> 6 are power lines while climbing
Burns in Adults are work related
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2nd leading cause of occupational deaths
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>90% male victims
Definitions
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Current (I)
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Volume of Electrons travelling between two points every second
Voltage (V)
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The force that drives the electrons across the potential difference
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High Voltage is > 1000V
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Low Voltage is < 1000V
Resistance (R)
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The hindrance to the flow of electrons
Current
Alternating Current
Direct Current
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Direction changes cyclically
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Found in households, businesses,
industries
Direction of the current remains
constant
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Batteries, Railroads, Cars, Lightning
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Household current is 60hz
Physics
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Ohm’s Law
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Voltage (V) = Current (I) x Resistance (R)
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V=IxR
Joule’s Law of Heating
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Heat (P) = Current (I) x Voltage (V) x Time of contact (t)
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P=IxVxt
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P = I² x R x t
Resistance
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P = I² x R x t
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Heat and Resistance are proportional
Greatest to least resistance
1.
Bone
2.
Fat
3.
Tendon
4.
Skin
5.
Muscle
6.
Blood Vessels
7.
Nerves
High or Low Voltage
High or Low Voltage
High or Low Voltage
High or Low Voltage
High or Low Voltage
High or Low Voltage
Mechanisms of Injury
1.
2.
Direct effect on tissues
1.
Arrhythmias
2.
Apnea
Blunt mechanical injuries
1.
Muscle contraction
2.
Falls
3.
Conversion of electrical to thermal energy
4.
Electroporation
1.
Disruption of cell membrane
2.
Loss of ion gradient
Respiratory
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Inhibition of CNS Respiratory Drive
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Paralysis of Respiratory Muscles
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Cardiorespiratory arrest from V.Fib or Asystole
Cardiovascular
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Arrhythmias
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V. Fib most common from AC
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Asystole most common from DC or high-voltage AC
Conduction Abnormalities
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Sinus Bradycardia
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High degree AV blocks
Myocardial Injury
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From electro-thermal conversion and electroporation
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Ck-MB is often elevated, Troponin not well studied in this setting
Vascular Injuries include coagulation and aneurysm formation
Neurological
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Loss of Consciousness
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Autonomic Dysfunction
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Respiratory Depression
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Memory Loss
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Sensorineural Hearing Loss
Skin
1.
Electro-thermal burns
2.
Arc burns
3.
Flame burns
Electro-thermal burns
Arc Burns
Flame Burns
Musculoskeletal
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Joint dislocation
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Muscular Thermal Injury
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Rhabdomyolysis
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Compartment Syndrome
Electrical Weapons
Electrical Weapons
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NO evidence of dangerous lab abnormalities, physiologic changes,
immediate or delayed cardiac ischemia or arrhythmia for exposures
15 seconds or less
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No need for diagnostic testing in otherwise asymptomatic alert
patients
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Fatal arrhythmia has been reported in some cases
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Concurrent intoxication with cocaine, PCP, Meth can increase risk
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Preexisting cardiovascular disease may increase risk
Injuries may occur after falling from being stunned
Management
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Cardiopulmonary Resuscitation
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Most victims are young and have good outcomes
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Prolonged CPR regardless of initial rhythm
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In mass casualty events triage protocols should be reversed
Cardiac Assessment
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Evaluation with ECG AT LEAST for every High Voltage injury
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Hemodynamic monitoring as high incidence of arrhythmia
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CK-MB is poor and Troponin has not been studied
Management
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Fluid Resuscitation
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Burn percentage is severely underestimated
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Parkland formula can not be used
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Maintain UOP > 1cc/kg/hr for adults
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Abdominal Compartment Syndrome
Gastrointestinal Injuries
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Rare, however case reports of perforations
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Vascular injuries
Disposition
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High voltage injuries
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Disposition based on injuries
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If asymptomatic STILL 12-24 hours of cardiac monitor
Low voltage injuries
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Disposition based on injuries
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If asymptomatic no tests required and can be discharged
Sources
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Chalkias A, Iacovidou N, Xanthos T. Continuous chest compression pediatric
cardiopulmonary resuscitation after witnessed electrocution. Am J Emerg Med.
2014;32:(6)686.e1-2. [pubmed]
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Marques EG, Júnior GA, Neto BF, et al. Visceral injury in electrical shock trauma:
proposed guideline for the management of abdominal electrocution and
literature review. Int J Burns Trauma. 2014;4:(1)1-6. [pubmed]

Schwarz ES, Barra M, Liao MM. Successful resuscitation of a patient in asystole
after a TASER injury using a hypothermia protocol. Am J Emerg Med.
2009;27:(4)515.e1-2. [pubmed]
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Spies C, Trohman RG. Narrative review: Electrocution and life-threatening
electrical injuries. Ann Intern Med. 2006;145:(7)531-7. [pubmed]
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Rechtin C, Jones JS. Best evidence topic reports. Bet 2: Cardiac monitoring in
adults after taser discharge. Emerg Med J. 2009;26:(9)666-7. [pubmed] Roberts S,
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Meltzer JA. An evidence-based approach to electrical injuries in children.
Pediatr Emerg Med Pract. 2013;10:(9)1-16; quiz 16-7. [pubmed]