Transcript Lightning Injuries - Adirondack Area Network

Lightning Injuries
Michael W. Dailey, MD
Assistant Professor of Emergency Medicine
Albany Medical College
Overview
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General
Lightning Myths
Severity of injuries
Triage considerations
Clinical Findings
Long term effects
Prevention
General
• 50,000 thunder storms and 8 million lightning
strikes in any given day
• Lightning strikes earth more than 100 x a sec
• 1000 fatalities worldwide/year
• Recreational injuries are increasing but 25% of
deaths and 29% of injuries are still employment
related
• High Mountain environment = 5x more lightning
strikes per year
Frequency of Injury and Death
• 150 - 250 deaths/year in the U.S.
• 4 - 5 times more injuries
• Lightning kills more people in the US each
year than any other natural disaster
– 55% more deaths than tornadoes
– 41% more deaths that floods and hurricanes
combined
Incidence of Lightning Injuries
• Most in the South, Rockies, along the
Atlantic Coast, and in the river valleys of
the Hudson, Ohio, and Mississippi Rivers
• Occur more often in thunderstorm season May to September
• Occur more often in afternoon and early
evening
Who Gets Struck?
• In early century most common in farmers
• Now, golfers, climbers, joggers and other
outdoor athletes, and construction workers
• Lightning injuries tend to involve more than
one victim
• 15 % of deaths occur in multiples of 2
• 15% occur in multiples of 3 or more
Lightning Production
• Warm, low pressure air moving through
cool, high pressure air produces static
• The friction of moving air particles within
the cloud causes ionization and complicated
energy charges
Lightning Myths
1) Lightning is always fatal
2) “Spontaneous Combustion and Crispy Critters”
3) Lightning never strikes in the same place twice
4) Victims remain electrified
5) “Suspended Animation”
6) Lightning injuries are like other high voltage
injuries
Lightning Truths
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Victims do not remain electrified
Lightning is fatal 20 - 30% of the time
Lightning rarely causes deep burns - < 5%
Lightning frequently strikes the same place
multiple times - Sears Tower = > 1000/yr
• No studies have shown outcomes of cardiac
arrest are different from other mechanisms
Lightning vs. High Voltage
• Much less energy imparted in lightning strikes
• Therefore much less injury
• The body’s electrical system may be “shortcircuited” resulting in cardiac and respiratory
arrest, tinnitus, temp blindness,paralysis
• DO NOT see deep burns or myoglobinuria
Mechanism of Lightning Injury
1) Direct Strike
2) Contact - Person touching object struck
3) “Splash” - lightning jumps from its
pathway and patient becomes pathway
4) Ground current - current spreading radially
through the ground
5) Blunt injury
Severity of Injury
1) AC vs. DC
2) Duration
3) Voltage
4) Amperage
5) Resistance of Tissues
6) Pathway
Alternating and Direct Current
• AC - electron flow changes direction on
cyclic basis ( household current = 60
cycles/sec) - More dangerous
• DC - no change in flow
• Lightning - oscillations are so rapid, in
effect a direct current
• As DC - will cause asystole (not fibrillation)
Voltage, Amperage, and Duration
• Average voltage = 10-20 million volts
• High voltage wires =15,000 volts
• Amperage = 20,000 - 100 million
• Because duration is VERY short (1/10,000 1/1000 sec) the actual amount of energy
delivered is very small
– 10,000,000 V x 1/1000 sec = 10,000 W-sec
– 15,000 V x 120 sec = 1,800,000 W-sec
Flash Over
• The short duration of lightning injury
seldom allows energy time to break down
skin and cause significant internal current
flow or tissue damage
• Small amount of energy “leaks” internally,
disrupting cardiovascular, pulmonary, and
autonomic systems
Triage Considerations
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Major cause of death is cardio-respiratory arrest
Concentrate on those in arrest
Absence of arrest, pts are highly unlikely to die
Ventilation is key if not in arrest
Head and Neck
• > 50% of victims have at least 1 tympanic
membrane ruptured
• Skull fractures and C-spine Injuries
• Disruption of ossicles/mastoid
• Permanent Deafness
• Cataracts - corneal lesions, uveitis,
iridcyclitis, hyphema, retinal detachment
Cardiopulmonary
• Pulmonary Contusion/Hemorrhage
• Numerous Dysrhythmias
• Nonspecific ST changes –
rarely true evidence of infarction
• Hypertension present early –
resolves in 1 - 2 hours
Cardiopulmonary Arrest
• Lightning sends heart into asystole and paralyses
respiratory center in brain
• Automaticity MAY lead to the heart restarting
• Respiratory paralysis lasts longer - leading to a
secondary cardiac arrest
• IF THE PT IS VENTILATED - MAY AVOID
SECONDARY ARREST!!!
Extremities
• Numerous fractures and dislocations reported
• Permanent paresis or paresthesias
• Keraunoparalysis - blue, mottled, cold, and
pulseless extremities due to vascular spasm and
sympathetic nervous system lability
- usually clears in a few hours
Skin
• Burns are usually superficial if present at all
deep burns occur in 5%
• Four types of superficial burns
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Linear - from steam production and flashover
Punctate - appear as cigarette burns
Feathering - not true burns, electron showers
Thermal - from ignited cloths or metal
Other Injuries
• Neurologic
– Sz, Deafness, Confusion/Amnesia, Blindness
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Concussion from shock wave
Chest pain/muscle aches
Blunt Abdominal Trauma
Intracranial Hemorrhages
Delayed Injuries
• Dysesthesias
• Peripheral neuropathy
• Decreased fine motor
function
• Neuropsychologic
changes
– memory difficulties,
depression, anxiety,
insomnia,and PTSD
• From Hypoxic Cerebral
Damage
– Seizures and Severe
Brain Damage
• From Vascular Spasm
– Spinal Artery Syndromes
Prehospital Treatment
• Triage Considerations
• A,B,C,D,E - with special attention to those in
cardiac arrest (standard treatment)
• Treatment of seizures is standard
• Treat Hypothermia (many pts are wet)
• IV access and fluids
• Expeditious, safe, transport
Hospital Treatment
• ECG and Cardiac Monitoring
• Labs
– CBC, Lytes, U/A, CPK with isos, appropriate Xrays/CT/MRI
• Admit for 24 hours - appropriate treatment of
dysrythmias
• Those who DO NOT suffer cardiopulmonary arrest
do well - those who do have a poor prognosis
Back Country Prevention
• Avoid high risk situations - BEFORE trip
• Try to seek shelter - tents are poor protection
(metal poles and wet items in tent)
• Avoid lone trees, ridge tops, clearings
• Crouch down or kneel in forested area with
small trees
• Sitting on pack may prevent step voltage
General Prevention
• If outdoors during thunderstorm, do not
gather under trees
• Soccer fields, baseball diamonds and tennis
courts are dangerous
• Get away from large open areas of land
• Greens are a bad choice
• Time for the 19th hole!