Transcript 2013-gemc-res-lex-electrical_misadventures-oer

Project: Ghana Emergency Medicine Collaborative
Document Title: Electrical Misadventures
Author(s): Joe Lex, MD, FACEP, FAAEM, (Temple University) 2013
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Electrical Misadventures
Joe Lex, MD, FACEP, FAAEM
Department of Emergency Medicine
Temple University School of Medicine
Philadelphia, PA
Objectives
Discuss controversies about…
…microwave injuries
…cord-biting injuries
…lightning injuries
…TASER® injuries
Steve and Sara, Flickr
Objectives
• Explore some controversies in
management of electrical injuries
• Determine who really requires
hospital admission
• Discuss how pregnancy changes
management
Microwave
Mk2010, Wikimedia Commons
Microwave
• More similar to electric burns than
to conventional oven burns
• Tend to be sharply demarcated
• Can burn skin and muscle, but
not hurt subcutaneous tissues
• Biopsy  layered sparing
Microwave
Source: Dixon JJ, et al. Burns. 1997
May;23(3): 268-8.
Source: Dixon JJ, et al. Burns. 1997
May;23(3): 268-8.
Cord Biting Injury
Fg2, Wikimedia Commons
Cord Biting Injury
Source Undetermined
Cord Biting Injury
• Chew through cord insulation
• Most injuries unilateral: lateral
commissure, tongue
• Systemic problems uncommon
• Labial artery injury not apparent
immediately due to vascular
spasm, thrombosis, eschar
Cord Biting Injury
• Severe bleeding from labial artery
in up to 10% when eschar
separates, usually 5 days – 2
weeks
• Old recommendation: admit
• Newer recommendation: reliable
parents  outpatient adequate
Garcia CT, et al. Ann Emerg Med. 1995 Nov;26(5):604-8.
Lightning Injury
National Oceanic and Atmospheric Association,
Wikimedia Commons
Lightning Injury
• Annual US Deaths Reported: 60
• Annual US Injuries Reported: 400
• Odds of being struck by lightning
in a given year: 1/400,000
• Odds of being struck in your
lifetime: 1/5000
Lightning Injury
Source: New England Journal of Medicine
Lightning Injury
James Heilman, MD, Wikimedia Commons
Lightning Injury
• Typical industrial shock: 20 – 63
kilovolts
• Lightning strike: 300 kilovolts
• Industrial shocks rarely last
longer than 500 milliseconds
• Lightning strikes last only few
milliseconds
Lightning Injury
• Unlike other multiple victim
trauma, give priority to people
who appear dead
• Aggressively resuscitate; survival
has been reported after
prolonged respiratory arrest
• Immobilize spine when mental
status altered
Lightning Injury
• Hypotension is unexpected and
should prompt investigation for
hemorrhage
• Treat ventricular tachycardia or
fibrillation and asystole with
standard ACLS protocols
• Treat seizures with standard
therapy
Lightning Injury
• Admit patients with minor injuries
for cardiac and neurologic
monitoring
• Admit all pregnant patients for
fetal monitoring
Taser
United States Military, Wikimedia Commons
Taser
• Series of damped sinusoidal
electrical impulses designed to
induce involuntary muscle
contraction and incapacitation
• High voltage (50 kilovolt) low
amperage, low average energy
Taser
• Uses Electro-Muscular Disruption
(EMD) technology to cause
neuromuscular incapacitation
(NMI) and strong muscle
contractions through involuntary
stimulation of both sensory and
motor nerves
Taser
• Considered safe
• Function appropriately on calm,
healthy, individual in relaxed and
controlled environment
• 2001-2007: >245 deaths
occurred after Taser use
http://www.amnesty.org/en/library/info/AMR51/030/2006
Taser
• 7 cases: ME said Taser was
cause or contributing factor
• 16 cases: ME said Taser was
secondary or contributory factor
• Dozens of cases: ME cited
excited delirium (not in DSM-IV)
• Several cases: fall caused by
Taser implicated as cause
http://en.wikipedia.org/wiki/Taser_safety_issues
Taser
• ACEP now recognizes “excited
delirium” as a diagnosis
• Doubt other specialties will join us
– they don’t see what we see
• Should help exonerate some lawenforcement people accused for
“deaths in custody”
Taser
• But no evidence taser on chest
can cause R-on-T phenomenon,
leading to Vfib and death
• No evidence taser can cause
malfunction of pacemaker or
AICD
• Should victims be monitored? No
clear evidence
Heart Rhythm Society. Abstract presented 5/11/07.
Taser
• Go to 1:25
• Series
Electrical Shock Injury
Magnus Manske, Wikimedia Commons
Some Epidemiology
• Severe nonlethal electrical
injuries account for 3 to 5% of
admissions to burn centers
• About 17,000 victims of electrical
injury treated each year in U.S.
emergency departments
Some Epidemiology
Three distinct populations at risk
• Toddlers: household electrical
sockets and cords
• Adolescents: risky behavior
around electrical power lines
• Electrical utility workers: annual
death in US of ~1 per 10,000
Some Epidemiology
• Easy electric flow: conductors
• Poor electric flow: insulators
• Best conductors: tissues with
high fluid and electrolyte content
Some Epidemiology
• High voltage  severe burns
despite fraction of a second
contact time
• Household voltages (110v) 
minimal burns, even after several
seconds of contact time
Some Epidemiology
• Even in low-voltage electrocution
deaths, electrical burns absent in
> 40% of cases
• Somebody “thrown” from electric
source actually having tetany
• AC current can also cause flexor
tetany  unable to release
Types of Burns
• Flash burns: heat from nearby arc
causes thermal burns
• Electrothermal burns: current
passage through body
• Flame burns: clothing ignition
• Arc burns: current arcs to victim
– May be mix of flash, electrothermal
and flame
Flash Burns
Ben Watts, Flickr
Flash Burns
Source Undetermined
Electrothermal Burns
Occupational Safety and Health Administration, Wikimedia Commons
Electrothermal Burns
Source Undetermined
Electrical Arc
• Spark of current through air
between objects of differing
electrical potential
• Typically source to patient
• Voltages are extreme
• Temperatures can reach
2500°C (4532°F)
Arc Burns
Source Undetermined
High vs. Low Voltage
• Brief dose of high voltage
electricity is not necessarily fatal
• Low voltage just as likely to kill as
high voltage
Sonarpulse, Wikimedia Commons
RK Wright, et al. J. Forensic Sci. 1980; 25:514-521.
Specific Injuries: Cardiac
• Low-voltage AC: VFib
• High-voltage AC, DC: transient
ventricular asystole
• Cardiac arrhythmias in up to 30%
of high-voltage victims
– Sinus tach, PACs, PVCs, SVT,
AFib, 1o or 2o AV block
Specific Injuries: Cardiac
All stops out resuscitation
1) many victims young, no prior
cardiovascular disease
2) often not possible to predict
outcome based on age and initial
rhythm
Specific Injuries: CNS
• Neurologic impairment in ~50%
with high-voltage injuries
• Transient loss of conscious
common
• Others: agitation, coma, seizures,
confusion, quadriplegia, aphasia
hemiplegia, vision changes
Specific Injuries: Spinal Cord
• Immediate from vertebral
fractures, usually found in workup
• Delayed from electrical current
itself: may present as ascending
paralysis, complete or incomplete
spinal cord syndromes,
transverse myelitis
Specific Injuries: Spinal Cord
• If purely electrical, MRI results not
closely correlated with prognosis
– Rarely initial MRI will be normal in
electrical trauma patients with
permanent spinal cord injury
– Majority of patients with spinal cord
impairment following mechanical trauma
who have a normal initial spinal MRI will
have complete resolution of neurologic
dysfunction
Specific Injuries: Peripheral
• Peripheral nerve injuries often
involve hands
• Paresthesias can be immediate
and transient or delayed up to 2
years after injury
• Contact with palm produces
median or ulnar neuropathy more
than radial nerve injury
Specific Injuries: Eyes
• Cataract formation described
weeks to years after electrical
injury to head, neck, upper chest
• Also reported after electric arc or
flash burns
• High-voltage: retinal detachment,
corneal burns, intraocular
hemorrhage and thrombosis
Specific Injuries: Shoulders
• Posterior dislocations and
scapular fractures both reported
Source Undetermined
Specific Injuries: Pregnancy
• Case reports of pregnant women
receiving apparently harmless
contacts with electric current later
suffering fetal damage or loss
• In most cases, mechanism of
fetal injury is uncertain
Fatovich DM. J Emerg Med. 1993 Mar-Apr;11(2):175-7.
Specific Injuries: Pregnancy
1) Monitor fetal heart rate and
uterine activity for 4 hours if
>20-24 weeks’ gestation
2) Monitor maternal cardiac and
fetal heart rate and uterine
activity for 24 hours if ECG
changes, loss of consciousness,
history of heart disease
Fatovich DM. J Emerg Med. 1993 Mar-Apr;11(2):175-7.
Specific Injuries: Pregnancy
• Fetal ultrasonography also
recommended immediately and
at 2 weeks, but…
• No proof that monitoring or
treatment can influence fetal
outcome in pregnant women
following electric injury without
mechanical trauma
Einarson A, et al. Am J Obstet Gynecol. 1997 Mar;176(3):678-81
Cardiac Monitoring
James T at al. Cardiac abnormalities
demonstrated post-mortem in four cases of
accidental electrocution and their potential
significance relative to non-fatal electrical injuries
of the heart. American Heart Journal. 120: 14357, 1990.
Robinson N et al. Electrical injury to the heart
may cause long-term damage to conducting
tissue: a hypothesis and review of the literature.
Int J Cardiol. 53: 273-7, 1996.
Cardiac Monitoring
Alexander L. Electrical injuries of the nervous
system. J Nerv Ment Dis 1941; 94: 622-632
Jensen PJ, et al. Electrical injury causing
ventricular arrhythmias. Br Heart J 1987; 57:
279-283
Norquist C, et al. The risk of delayed
dysrhythmias after electrical injuries. Acad
Emerg Med. 6: 393, 1999
Cardiac Monitoring
• Common knowledge: All patients
with electrical injury require 24
hours of cardiac monitoring
Bionerd, Wikimedia Commons
Cardiac Monitoring
Voltage
Number
of
patients
Initial
ECG
Normal
Initial
ECG
Abnormal
Late
Rhythm
Problems
1000
48
40
8
< 1000
35
31
4
Moran and Munster
110 – 850
42
40
2
0
0
0
Kirschmair and Denstl
220 – 900
19
15
4
Fatovitch and Lee
240
20
18
2
Cunningham
240
70
59
11
> 220
31
29
2
Bailey, et. al.
120 & 240
120
119
1
Arrowsmith
> 220
73
69
4
9 articles
Authors
Purdue and Hunt
Wrobel
Kreinke and Kienst
0
0
0
0
0
0
Cardiac Monitoring
• Not justified in asymptomatic
patient
• Not justified in patient with only
cutaneous burn
• Not justified in patient who has
normal ECG after a 120v or 240v
injury
Felt current pass
through body
No
Was held to source
of electric current
No
Lost
consciousness
No
Voltage source
>1000 volts
No
Current passed
through heart
Held to source
for >1 second
Cardiac monitor for
24 hours
Burn marks on skin
Evaluate and treat
burns
No
Thrown from source
Evaluate and treat
trauma
No
Pregnant
Evaluate fetal
activity
No
BENIGN SHOCK
Reassure and release
Indications for Heart Monitor
1.
2.
3.
4.
Loss of consciousness
Cardiac dysrhythmia
Abnormal ECG
Abnormal mental status or
physical examination
5. Injury expected to cause
hemodynamic instability or
electrolyte problem
Fish RM. J Emerg Med. 2000 Feb;18(2):181-7.
Failure to Document Normals
Conditions that can arise after
initial presentation include
• Cataracts
• Vascular occlusion
• Compartment syndrome
• Brain and spinal cord dysfunction
Summary
• Electrical injuries involve multiple
body systems
• Entry and exit wounds fail to
reflect true extent of underlying
tissue damage
• Electrical current may cause
injuries distant from its apparent
pathway through the victim
Summary
• Controversies exist regarding
indications for admission and
cardiac monitoring following low
voltage injuries
Thank you