Transcript ELECTRICAL INJURIES - University of Tennessee Health

Rami Khouzam, MD
The Statue of Zeus at Olympia
• An enormous statue of the
Greek father of gods, carved
by the great sculptor Pheidias
• In his right hand a figure of
Victory made from ivory and
gold. In his left hand, his
scepter inlaid with all metals,
and an eagle perched on the
sceptre
• The sandals of the god are
made of gold, as is his robe
Pausanias the Greek (2nd century AD)
7 Wonders of the Ancient World
• Today, archaeological evidence reveals some of the
mysteries that surrounded the history of the Wonders
for centuries
• For their builders, the Seven Wonders were a
celebration of religion, mythology, art, power, and
science
• For us, they reflect the ability of humans to change
the surrounding landscape by building massive yet
beautiful structures, one of which ( the Pyramid)
stood the test of time to this very day
Index Case
• 42-year-old white male
• No significant past medical hx. except x
possible marijuana
• Was working on a ladder 12 feet high
• Electrocuted with 440 volts
• Contact burns to bilateral hands
• Prior to arrival to the hospital:
• SVT --> Cardioversion x 5
• Hypotension --> Dopamine and Epinephrine
drips
• Intubated
• Vitals on arrival:
– Pulse: 101
– BP: 71/46
– RR: 24
PE (pertinent findings):
• Neck in C-collar
• Ears: some blood behind Lt. tympanic
membrane
• Chest: Bilateral crackles
• Heart: S1S2 RRR Few extra-beats, No m,g,r
• Upper extremities: 2nd & 3rd degree burns on
the palmar aspects of both hands
• Labs:
•
•
•
•
•
•
K: 3.1, Cr: 1.1
WBCs: 27.8  10.5
AST/ALT: 63/54
ABGs: 7.25/43.8/213.7/18.6/99.1%
Lactic a: 4.2
UDS: + methamphetamine
Trop
CK
CKMB
CKMB index
Myoglobin
1.38
989
19.4
2.0
> 500
2.87
1.81
2190
17.2
0.8
> 500
•
•
•
•
•
•
Swan-Ganz:
PCWP: 19
PA: 31/14
CVP: 15
CO: 16 / CI: 11
SVR: 335
MAP: 80
CXR:
• Interstitial & alveolar pulmonary opacities
centrally with relative sparing peripherally:
consistent with pulmonary edema
TTE on admission
• Mild eccentric LVH
• LV systolic function was moderately to
severely decreased
• EF: 25-30%
Day 3:
• Levophed discontinued
• Weaned off of the vent & extubated
• Blood culture: MRSA
Day 8:
• Discharged home on: pain meds &
antibiotics
TTE (prior to d/c)
• Normal left ventricular systolic function
• EF: 65%
The Hanging Gardens of Babylon
• A palace with
legendary gardens
built on the banks
of the Euphrates
river by King
Nebuchadnezzar II
ELECTRICAL INJURIES
Critical Care Medicine
Volume 30.Number 11.November 2002
• Adults in workplace, children at home
• Severity of injury depends on:
– Intensity of electrical current (voltage of
source and resistance of victim)
– Pathway through victim’s body
– Duration of the contact with the source
Immediate death may occur from:
1) Current-induced ventricular fibrillation
2) Asystole
3) Respiratory arrest secondary to:
– Paralysis of the central respiratory control
system
– Paralysis of the respiratory muscles
History Overview
• Lightning was
attributed to
supernatural powers
• Zeus ruler of the
ancient Greek gods
holding
thunderbolts which
he used as warning
or punishment
against who
disobeyed him
• Zeus, the youngest son of Cronus and Rhea,
was the supreme ruler of Mount Olympus and
of the Pantheon of gods who resided there
• Being the supreme ruler he upheld law, justice
and morals, and this made him the spiritual
leader of both gods and men
• Zeus was a celestial god, and originally
worshiped as a weather god by the Greek
tribes
• He has always been associated as being a
weather god, as his main attribute is the
thunderbolt, he controlled thunder, lightning
and rain
• Theocritus wrote circa 265 BCE: "sometimes
Zeus is clear, sometimes he rains”
• He is also known to have caused
thunderstorms
• Discovery and
widespread use of
electricity in the mid1800s took away the
supernatural aura
• 1st electrical fatality
recorded in France
in 1879
• Thomas Alva Edison was both a scientist
and an inventor
• Born in 1847
• When Edison was born, society still thought
of electricity as a novelty, a fad. By the time
he died, entire cities were lit by electricity
• In his lifetime, Edison patented 1,093
inventions
• The most famous of his inventions was an
incandescent light bulb
• He believed in hard work, sometimes
working twenty hours a day. Edison was
quoted as saying, "Genius is one percent
inspiration and 99 percent perspiration"
• In tribute to this important American,
electric lights in the United States were
dimmed for one minute on October 21,
1931, a few days after his death
• Electrical injuries (excluding lightning)
are responsible for > 500 deaths/year in
the US
• > 1/2 of them occur in the workplace.
• 4th leading cause of work-related
traumatic death
• Electrocutions at home: > 200
deaths/year
• Lightning responsible for 93 deaths/year in
US
• Morbidity 5-10 times higher than that due to
other forms of electrical injury
• Iatrogenic electrical injury in the ICU:
defibrillators, pacemakers, electrosurgical
devices
• Story of CPR: how to treat electrocuted
electrical linemen who were in VF
Principles of Electricity
• Electricity: flow of electrons (negatively
charged outer particles of an atom)
through a conductor
• When the electrons flow away from this
object through a conductor they create an
electric current: amperes
• Voltage: force that causes electrons to
flow: volts
• Anything that impedes the flow of
electrons through a conductor creates
resistance: ohms
• Power lines range from:
– Low: < 600 volts
– Ultrahigh: > 1 million volts
• Utility power lines with high voltages in
sparsely populated areas
• Through a succession of transformers voltage
is gradually reduced
• Most homes in US & Canada have a 120/240 V
other countries (Europe, Asia..): 220 V
The Temple of Artemis at Ephesus
• A beautiful temple
in Asia Minor
erected in honor of
the Greek goddess
of hunting and
wild nature
Pathophysiologic effects of
Different Intensities of
Electrical Current
• Electrical current exists in 2 forms:
1) AC: (Alternating Current): when
electrons flow back and forth through a
conductor in a cyclic fashion
• It is used in household and offices and is
standardized to a frequency of 60
cycles/sec (60 Hz)
2) DC: (Direct Current): when electrons
flow only in one direction
• Used in certain medical equipment:
defibrillators, pacemakers, electrical
scalpels
• AC is far more efficient and also more
dangerous than DC (~ 3 times): tetanic
muscle contractions that prolong the
contact of victim with source
• Issue of safety over efficiency: early days
of electricity when Thomas Edison (who
developed and popularized DC was
fighting against George Westinghouse
(who developed AC)
• AC: first death penalty by electrocution
• Lightning is a form of DC
• Occurs when electrical difference
between a thundercloud and the ground
overcomes the insulating properties of the
surrounding air
• Current rises to a peak in about 2 µsec
• Lasts for only 1-2 sec
• Voltage >1,000,000 V
• Currents of >200,000 A
• Transformation of the electrical energy to
heat generated temperatures as high as
50,000ºF
• Extremely short duration prevents from
melting
The Mausoleum at Halicarnassus
• A fascinating
tomb constructed
for King
Maussollos,
Persian satrap of
Caria
Determinants of Electrical Injuries
• Ohm’s law:
Current = Voltage/Resistance
• Exposure of different parts of the body to
the same voltage  different current 
different degree of damage because
resistance varies
• The least resistance is found in nerves,
blood, mucous membranes and muscles
• The highest resistance is found in bones,
fat and tendons
• Skin’s resistance ranging between 40,000
and 100,000 Ω depending on thickness
• Moisture of the skin; electrocution of a
person in a bathtub or swimming pool
• Moist mucus membranes: significant
orofacial injury to infants and toddlers
• Nerves and blood vessels are the best
conductors: path of least resistance for
current after it enters the body
• Duration of the contact: shock caused by
AC will produce bigger injury than shock
caused by DC of the same amperage
Pathway of the current through the body:
– Vertical pathway parallel to the axis of the
body is the most dangerous. It involves all the
vital organs; central nervous system, heart,
respiratory muscles, in pregnant women the
uterus and fetus
– Horizontal pathway from hand to hand: the
heart, respiratory muscles and spinal cord
– Pathway through the lower part of the body:
local damage
The Colossus of Rhodes
• A colossus of
Helios the sungod, erected by
the Greeks near
the harbor of a
Mediterranean
Island
Electrical Injury to Specific
Tissues & Organs
Cardiovascular System:
Pathophysiology:
• Direct necrosis of the myocardium
• Cardiac dysrhythmias
• Focal or diffuse
• Widespread, discrete, patchy contraction
band necrosis involving the myocardium,
nodal tissue, conduction pathways and
coronary arteries
• A current > 50-100 mA with hand-tohand or hand-to-foot transmission 
ventricular fibrillation
• High-voltage current (AC or DC) 
ventricular asystole
• Lightning  cardiac standstill
• Sinus rhythm may spontaneously return
• Cardiac dysrhythmias reported in
survivors of electrical injuries
pathogenesis is rather unclear,
multifactorial
• Possible mechanisms:
1) Arrythmogenic foci due to myocardial
necrosis (esp. SA Node injury)
2) Alterations in the Na+ - K+ adenosine
triphosphatase concentration
3) Changes in the permeability of myocyte
membranes
4) Anoxic injury (respiratory arrest precedes
the injury to the heart)
• Large arteries not acutely affected
because their rapid flow:dissipate
heat. Medial necrosis: aneurysm
formation and rupture
• Smaller vessels acutely affected d.t.
coagulation necrosis  compartment
syndrome
Clinical Manifestations
• Cardiac standstill, ventricular fibrillation:
most serious
• Sinus tachycardia, nonspecific ST- and Twave changes: much better prognosis
• Conduction defects, various degrees of
heart blocks, BBB and QT interval
• Supraventricular tachycardias and atrial
fibrillation: usually do not cause
significant hemodynamic compromise
• On echocardiogram: some depression
of the right & left ejection fractions
Cutaneous Injuries & Burns
• Extensive flash and flame burns
• Hemodynamic, autonomic,
cardiopulmonary, renal, metabolic and
neuroendocrine responses
Nervous System
• Loss of conciousness, confusion & impaired recall
• Peripheral motor & sensory nerves  motor &
sensory deficits
• Seizures, visual disturbances & deafness
• Hemiplegia, quadriplegia, spinal cord injury
• Transient paralysis, autonomic instability 
hypertension, peripheral vasospasm due to lightning
from massive release of catecholamines
Respiratory System
• Direct injury to the respiratory control
center  cessation of respiration or
suffocation secondary to tetanic
contractions of the respiratory muscles
• Acute respiratory dysfunction syndrome
secondary to ischemia, aggressive fluid
resuscitation, ventilator-associated
pneumonia
Other Systems
• Kidneys susceptible to anoxic/ischemic injury
• Release of myoglobin & creatinine phosphokinase
 renal tubular damage  renal failure
• Fractures
• Transient autonomic disturbances  fixed pupils
may be perceived as severe brain injury or even
death
• Temporary sensorineural hearing loss
The Lighthouse of Alexandria
• A lighthouse
built by the
Ptolemies on the
island of Pharos
off the coast of
their capital city
Management of Electrical Injuries
Overall fluid management should be
judicious unless: SIADH
Patient Monitoring
• Most severe cardiac complications present
acutely
• Very unlikely for a patient to develop a
serious or life-threatening dysrhythmia
hours or days later
• Asymptomatic normal ECG do not need
cardiac monitoring
• Preexisting heart disease: monitor such
patients for 24 hrs after the injury
• Criteria for cardiac monitoring:
– Exposure to high voltage
– Loss of consciousness
– Abnormal ECG at admission
• Type of cardiac monitoring: (controversial)
– Continuous telemetry
– Serial ECGs
– Serial measurement of cardiac enzymes
• Prognostic value of CK-MB, noninvasive and invasive
imaging studies (echocardiography, thallium studies &
angiography): rather poor and inconsistent
• Muscles injured by an electrical current can contain up
to 25% CK-MB fraction (as opposed to the normal 23%)
• No information regarding changes in troponin
Prophylaxis...
“One ounce of prevention is worth a
pound of treatment”
The Great Pyramid of Giza
• A gigantic stone
structure near the ancient
city of Memphis, serving
as a tomb for the
Egyptian Pharaoh Khufu
“Man fears Time, yet Time
fears the Pyramids”
Arab proverb
"Genius is one percent inspiration and 99 percent perspiration."