Transcript Effect of electric current on human body

Effect of electric current on
human body
What is electric current?
What is making particles to
move?
Where can we meet with
electric current?
What are AC and DC?
Electric current in human body
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heart
muscles
brain
threshold of perception
let-go current
ventricular fibrillation (pacemaker
with defibrillaror)
Why AC is more danger than DC?
How can we calculate the value
of the current flowing through
any circuit?
I = U/R
Body resistance
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in ohms/cm2
resistance of dry, well-keratinized, intact skin
averages 20,000 to 30,000 ohms/cm2
for a thickly calloused palm or sole, it may be 2
to 3 million ohms/cm2
resistance of moist, thin skin is about 500
ohms/cm2
if the skin is punctured (e.g., from a cut or
abrasion or by a needle) or if current is applied to
moist mucous membranes (e.g., mouth, rectum,
vagina), resistance may be as low as 200 to 300
What about the heat effects of
electric current?
heat = amperage2 × resistance × time
Q=
2
I
. R. t
Symptoms and signs
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depend on the pathway of electric current
from arm to arm
from arm to foot
conduction between legs or leg and the
ground
electrical injuries to the head
in Czech republic in half of electric
injuries at home children under 5 y are
insulted
high voltage vs. low voltage injuries
(special category  bathtub accidents)
Ligthning injury
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Neuropsychologic damage, pain syndromes, and
sympathetic nervous system damage are the
most common long-term sequelae.
Cardiopulmonary arrest is the most common
cause of death.
Hypotension, fluid and electrolyte
disturbances, and severe
myoglobinuria may cause acute
renal failure. Dislocations, vertebral
or other fractures, blunt injuries, and
loss of consciousness may result
from powerful muscle contractions
or falls secondary to the electric
shock (eg, electricity can startle a
person, causing a fall).
Treatment
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separating the patient from the
current source
rapid cardiopulmonary
resuscitation (ABC)
care in hospital
Baseline assessment for all electric
injuries
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ECG
cardiac enzymes
urinalysis, especially for myoglobin
cardiac monitoring for 12 h
CT or MRI scan to rule out
intracranial hemorrhage.
If myoglobinuria is present, fluid
replacement and alkalinization
therapy is essential to reduce the risk
of renal tubular myoglobin
precipitation.Mannitol or furosemide
may be indicated to increase renal
flow
Victims of lightning injuries
Fluid restriction is the rule because of
potential brain edema.
Prevention
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respect in dealing with electricity
proper design, installation and
maintenance of all electric devices
education and care about children