Transcript Electrical Injuries

Electrical Injuries
http://www.carldbarnes.com/Practiceareade
scriptions6.aspx
Author: Anna Macdonald,
MD
Date Created: July 2012
http://www.youthedesigner.com/2010/11/30/
photos-of-lightning-30-electrifyingexamples/
Global Health Emergency Medicine Teaching Modules by GHEM is licensed under
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Learning Objectives
 To understand some basic pathophysiology
behind electrical injuries
 To describe the clinical features of
electrical injuries
 To review prehospital and ED management
 To highlight unique features of lightning
injuries
Case
 A 35 year old male electrician
 Was repairing some wiring at a construction site and
observed by coworkers to be thrown off of scaffolding
and lost consciousness briefly
 On arrival patient is awake and complaining of severe
bilateral arm pain
 HR 120, BP 140/80, RR 24, O2 98% RA
 You see burns to both hands
 What are your management priorities?
A quick physics lesson
 Joule’s Law
 P = I2Rt
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P is heat (joules)
I is current (amps)
R is resistance (ohms)
t is time (sec)
 Ohm’s Law
 I = V/R
 V is voltage
 Hence severity of injury is determined by:
 Voltage, resistance of tissue, time in contact with current
A little more physics
 Direct Current versus Alternating Current

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DC:
 Single muscle contraction
 Throws victim away from source
 Sources: batteries, high voltage power lines, lightning
 Usually causes visible burns at entry/exit sites
AC:
 Tetanic contraction
 Prolongs contact with source hence more dangerous
 Sources: most homes and offices
 May not cause discernable burns at entry/exit sites
Electrical injury
 Injury by 3 mechanisms
 Injury from current flow (direct contact)
 Arc injury (electricity passes through air)
 Electricity arcs at a temperature of 4000C,
causing flash burns
 Flame injury by ignition of clothing or
surroundings
Types of electrical injury
Electrical injury
High voltage
(>1000V)
Low voltage
(<1000V)
Lightning
Arc Injury
(flash burn
type injury)
Electrical arc
http://guides.wikinut.com/img/138a.2js40g7r7_o/Electrical-arc (accessed Sept 2012)
Comparing the different types
Lightning
High voltage
Low voltage
Voltage
>30,000,000 V
>1000V
<1000V
Current
>200,000 amps
<1000 amps
<240 amps
Cardiac arrest
asystole
Ventricular
fibrillation
Ventricular fibrillation
Muscle contraction
single
depends
Tetanic
Burns
Rare, superficial
Common, deep
Usually superficial
Rhabdomyolysis
uncommon
Very common
Common
Mortality
Very high
moderate
Low
High voltage versus low voltage
 High voltage (>1000V) injuries tend to have
higher rates of complications
 Amputations, fasciotomies
 Compartment syndrome
 Longer hospital stays, ICU stays, mechanical
ventilation
 Cardiac dysrhythmias, acute renal failure
 Higher body surface area burn
Injury distribution
 In adults, injuries tend to be occupational
and high voltage
 In children, injuries appear bimodal
 Young children < 6y tend to have low voltage
injuries from the household
 Adolescents and older children tend to have
high voltage injuries from playing near hightension lines
Resistance of tissues
 Low
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Nerves
Blood
Mucous membranes
Muscle
 Intermediate
 Skin (resistance will be
reduced by moisture)
 High
 Tendon
 Fat
 Bone
http://rrtelite.50webs.com/faid_electricshock.html
Pathway
 Path that current takes through body determines:
 Which tissues are at risk
 Across thorax  cardiac damage/dysrhythmias
 Across head  seizures, resp arrest, paralysis
 Severity of damage
 Less damage with less current density

Current through trunk will cause less damage than through a digit
 Shorter distance between contact points will cause less damage

Child chewing on electrical cord <<< same voltage with head to toe
pathway
Clinical features
 Head and neck
 Tympanic membrane rupture
 Temporary hearing loss
 Cataracts – may happen immediately or be
delayed
 Cardiovascular system
 Dysrhythmias – asystole, VF  cardiac arrest
 May also cause transient ST elevation, QT
prolongation, PVCs, Atrial fibrillation, bundle
branch blocks
Clinical features
 Skin
 Thermal burns at contact
points
 Kissing burn – current
causes flexion of extremity
 burns at flexor creases
 Burns around mouth
common in children who
chew on electrical cord
 * Careful with these as
separation of eschar can
cause delayed bleeding of
labial artery
http://www.forensicmed.co.uk/wounds/bu
rns/chemical-and-electrical-burns/
(accessed July 2012)
Rosen’s Emergency Medicine. Chapter
140 page 1897 -see references at end of
presentation for full reference
Clinical features
 Extremities
 Compartment syndrome – requires fasciotomies
 Damaged muscle  massive release myoglobin 
rhabdomyolysis  renal failure
 Vascular
 Thrombosis of vessels
 Damage to vessel walls  delayed rupture and hemorrhage
 Skeletal system
 Fractures/dislocations from trauma or from tetanic muscle
contractures (e.g. shoulder dislocations)
Clinical features
 Nervous system
 Brain
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Loss of consciousness (usually transient)
Respiratory arrest
Confusion, flat affect, memory problems
Seizures
 Spinal cord injury either immediate or delayed
 Peripheral nerve damage
Electrical burn - fasciotomy
http://burnssurgery.blogspot.ca/2012/07/electrical-contract-burnsbilateral.html#!/2012/07/electrical-contract-burns-bilateral.html (accessed Sept 2012)
Electrical injury - amputation
http://www.emedicinehealth.com/electric_shock/page10_em.htm (accessed Sept 2012)
Electrical injury
http://med.brown.edu/pedisurg/Brown/IBImages/Trauma/oralburn.html (accessed Sept 2012)
http://www.wefixwires.com/new_page_2.htm (accessed Sept 2012)
Out of hospital management
 Ensure scene safety
 Careful for live lines on the scene
 ACLS protocols as needed
 Fluid resuscitation with saline or ringers
lactate
 Spine immobilization if suspected trauma
ED assessment
 History
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AMPLE history
Details of the electrical source
LOC on scene
Prehospital interventions
 Physical exam
 Primary and secondary surveys as in ATLS
 Look carefully at every inch of skin for entry/exit
wounds
ED initial management
 ABCs, ACLS, trauma management as
needed
 Fluid resuscitation
 Parkland formula not helpful here as surface
wounds not reflective of more extensive
internal damage
 Titrate to urine output 0.5-1 cc/kg/hr
 ECG
 Analgesia!
Cardiac monitoring
Low voltage injury
< 1000 V
Normal ECG
Loss of consciousness
or
Documented dysrhythmia
or
Abnormal ECG
Discharge home
Admission with telemetry
Low risk patients
High risk patients
Cardiac monitoring
 But...
High voltage injury
> 1000 V
Normal ECG
??
Intermediate risk patients
Other cardiac issues
 Time of monitoring not known – usually up
to 24 hours, but data limited
 CK-MB may not be accurate at diagnosing
cardiac injury
Wound care
 Tetanus immunization
 Dress wounds – may use antibiotic
dressing like silver sulfadiazine or clean,
dry dressings
 No role for prophylactic systemic antibiotics
Rhabdomyolysis
 Check CK – measure of muscle injury, risk of
amputation, length of hospitalization
 Check urine for myoglobin (or assume
presence if urine is heme pigmented)
 Goal is to prevent renal failure
 Fluids to maintain urine output 1-1.5 cc/kg/hr
 Bicarb? Lasix? Mannitol?
 No evidence to prove any of these are helpful
Extremity injury
 Monitor for compartment syndrome
 Feel compartments, assess for pain on passive
extension, paraesthesias etc
 Compartment pressures should be < 30 mmHg
 Fasciotomy if needed
 May need carpal tunnel release if arm involvement
 Amputate non viable extremities/digits
 Splint in position of safety to prevent contractures
Position of safety
 35-40 degree extension
of wrist
 80-90 degree flexion of
MCPs
 Almost full extension of
PIP/DIPs
https://www2.aofoundation.org/wps/portal/!ut/p/c0/04_SB8K8xLLM9
MSSzPy8xBz9CP0os3hng7BARydDRwN39yBTAyMvLwOLUA93I4
MQE_2CbEdFAF3RnT4!/?segment=Thumb&bone=Hand&soloState
=true&popupStyle=diagnosis&contentUrl=srg/popup/further_reading/
PFxM2/78/78-5-postop_treat.jsp (accessed July 2012)
Incidence of injuries in all-comers in
one study - Maghsoudi 2007
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Fasciotomy – 1.5%
Escarotomy – 3.5%
Amputation – 7.4%
Skin grafting – 37.6%
Renal failure – 0.5%
Myoglobinuria – 9%
Incidence of injuries in high voltage
in another study – Arnoldo 2004
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Fasciotomy – 33.4%
Escharotomy – 4.5%
Amputation – 36%
Renal failure – 2.6%
Cataract – 2%
Cardiac arrest – 1%
Disposition
 Admit if:
 Needs cardiac monitoring (at least 12-24 hrs)
 Pregnant patient (for fetal monitoring)
 Other injuries (trauma) severe enough to warrant
admission
 Significant burns (consider transfer to burn center
 Most high voltage injury
Electrical injury summary
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ABCs, ATLS
Dysrhythmias – ACLS
Manage trauma and orthopedic injuries
Consider need for amputations, fasciotomies,
escharotomies
Consider myoglobinuria and rhabdomyolysis
Splinting, burn and wound care
Consider need for cardiac monitoring
 Abnormal ECG, dysrhythmia, loss of consciousness,
high voltage injury
Consider transfer to burn centre
Lightning injuries – clinical features
 Special case as is a massive current
impulse for a very short time
 Short time duration means minimal
burns, tissue destruction
 Main cause of death is cardiac arrest
 Higher mortality than other electrical
injuries
http://www.moonraker.com.au/techni/lig
htning-marine.htm (accessed July 2012)
Lightning injuries – injury pattern
 Cardiac
 Usually asystole instead of Vfib
 ENT
 Perforated tympanic membranes, displacement of
ossicles
 Cataracts (often delayed)
 Psychiatric
 PTSD, depression, chronic fatigue
Lightning injuries continued...
 Neurologic
 LOC, confusion, anterograde amnesia,
paraesthesias
 Keraunoparalysis – transient paralysis of
lower limbs (sometime upper) that are cold,
mottled, blue and pulseless – usually self
resolves in few hours
Lightning injuries
 Sometimes lightning injuries cause multiple
casualties
 Lightning victims may be:
 Apneic (from paralysis of respiratory control
centre)
 Pulseless (cardiac standstill)
 Dilated pupils from autonomic dysfunction
 And should not be triaged as per usual mass
casualty triage
Lightning injuries - burns
 4 patterns of burns
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Linear
Punctate
Feathering
Thermal
http://www.scienceinseconds.com
/blog/By-the-Power-of-Zeus
(accessed July 2012)
http://atlasemergencymedicine.org.ua/ch.1
6.htm (accessed
July 2012)
http://atlasemergencymedicine.org.ua/ch.1
6.htm (accessed
July 2012)
Feathering
Punctate
Linear
Lightning injuries - management
 ECG
 Cardiac biomarkers if ECG abnormal, chest
pain, altered mentation
 CT head if altered mentation
 Does not usually require aggressive fluid
resuscitation, fasciotomies etc
Long term sequelae
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Numbness, Weakness
Memory problems
Anxiety, depression, insomnia
Nightmares
PTSD
Long term sequelae
 High voltage injuries also tend to have
higher rates of…
 Neuropathic pain
 Neuropsychiatric symptoms
 PTSD
…Than low voltage injuries
Back to the Case
 A 35 year old male electrician
 Was repairing some wiring at a construction site and
observed by coworkers to be thrown off of scaffolding
and lost consciousness briefly
 On arrival patient is awake and complaining of severe
bilateral arm pain
 HR 120, BP 140/80, RR 24, O2 98% RA
 You see burns to both hands
 What are your management priorities?
Case
 ABCs
 Awake and talking, breathing comfortably
 2 large bore IVs to give 2L bolus normal saline
 Don’t forget spine precautions and c-collar
 Cardiac monitor and ECG
 Examine (and manage) as you would a trauma patient given
history of fall
 Analgesia
 Follow urine output to guide fluid therapy (at least 0.5-1 cc/kg/hr
or 1-1.5 cc/kg/hr if rhabdomyolysis)
Case
 Tetanus immunization, dress wounds
 Send labs including CK and urine for myoglobin
 Extremities (arms in this case)
 Neurovascular exam
 Assess for compartment syndrome – call surgeon if needs
fasciotomies or carpal tunnel release
 Admit to ICU setting
Quiz Question 1
 Name 5 things that affect the severity of
electrical injury:
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Type of circuit (AC vs DC)
Duration of contact with circuit
Resistance of tissues
Voltage
Amperage
Pathway of current through body
Quiz Question 2
 How do you best fluid resuscitate a patient
with electrical injuries?



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Use the Parkland formula
Use the rule of nines
Titrate to urine output 1-1.5 cc/kg/hr
Give 1 litre bolus
Quiz Question 3
 Name 6 indications for inpatient cardiac
monitoring in electrical injuries?
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Cardiac arrest
History of loss of consciousness
Abnormal ECG
Dysrhythmia observed
History of cardiac disease or significant risk factor for cardiac disease
Suspicion of conductive injury
Hypoxia
Chest pain
High voltage injury (>1000 V)
Quiz Question 4
 How do you treat rhabdomyolysis?
 Fluids to maintain UO of 0.5-1 cc/kg/hr and
sodium bicarb
 Fluids to maintain UO of 1-1.5 cc/kg/hr and
sodium bicarb
 Fluids to maintain UO of 0.5-1 cc/kg/hr
 Fluids to maintain UO of 1-1.5 cc/kg/hr
Summary
 Electrical injuries often have concurrent
traumatic injuries
 Fluid resuscitate as you would a crush injury
(titrate to urine output)
 Aim for higher urine output if rhabdomyolysis
 Remember indications for cardiac monitoring
 Do a thorough neurovascular exam on
extremities and monitor for compartment
syndrome
Electrical injury summary

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
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ABCs, ATLS
Dysrhythmias – ACLS
Manage trauma and orthopedic injuries
Consider need for amputations, fasciotomies,
escharotomies
Consider myoglobinuria and rhabdomyolysis
Splinting, burn and wound care
Consider need for cardiac monitoring
 Abnormal ECG, dysrhythmia, loss of consciousness,
high voltage injury
Consider transfer to burn centre
General References
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Chapters in Textbooks:
 Price TG and Cooper MA. (2010). Electrical and Lightning injuries. Marx JA,
Hockberger RS, Walls RM (eds). Rosen's Emergency Medicine: Concepts
and Clinical Practice. (pp 1893-1902). Philadelphia, PA.
Web Links:
 http://emedicine.medscape.com/article/770179-overview
Articles
 Arnoldo BD et al. Electrical Injuries: a 20 year review. J Burn Care &
Rehabil. 2004;25(6):479-484
 Czuczman AD, Zane RD. Electrical Injuries: A Review for the Emergency
Clinician. Emergency Medicine Practice. 2009;11(10).
 Koumbourlis A. Electrical Injuries. Crit Care Med 2002; 30:S424-30.
References cont…
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Maghsoudi H et al. Electrical and Lightning Injuries. J Burn Care
Res 2007;28:255-261.
Luz DP et al. Electrical Burns: a retrospective analysis across a 5year period. Burns 2009; 35:1015-1019.
Singerman J et al. Long-term sequelae of low-voltage electrical
injury. J Burn Care Res 2008; 29:773-777.
Chudasama S et al. Outcome of high voltage and low voltage
electrical burns. Annals of Plastic Surgery 2010; 64(5): 522-525.
Celik A et al. Pediatric Electrical injuries: a review of 38 consecutive
patients. J Pediatr Surg 2004; 39:1233-1237.
Opara KO et al. Pattern of severe electrical injuries in a nigerian
regional burn centre. Nig Jour Clin Prac 2006; 9(2): 124-127.
References cont...
 Bailey B et al. Experience with guidelines for cardiac monitoring
after electrical injury in children. Am J Emerg Med 2000; 18:6715.
 Zubair M, Bessner GE. Pediatric electrical burns: management
strategies. Burns 1997; 23:413-20.
 Purdue GF, Hunt JL. Electrocardiographic monitoring after
electrical injury: necessity of luxury. J Trauma 1986; 26:166.
 Bailey B et al. Cardiac monitoring of high-risk patients after an
electrical injury: a prospective multicentre study. Emerg Med J
2007; 24:348-352.
 Arnoldo B et al. Practice Guidelines for the management of
electrical injuries. J Burn Care Res 2006; 27(4): 439-447.
References cont...
 Arrowsmith J et al. Electrical injury and the frequency of cardiac
complications. Burns 1997; 23: 576-578.
 Jensen PJ et al. Electrical injury causing ventricular arrhythmias.
Br Heart J 1987; 57:279-83.