5 electrocution

8/12/2019 5 Electrocution

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ELECTROCUTION

BY

ANGELIE OROPILLA, MD


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ELECTROCUTION

Almost always due to alternating current (35-150 Hz)

Human beings are 4-6x more sensitive to alternatingcurrent (AC) than direct current (DC)

Amperage is the most important factor

Current is directly related to voltage and inverselyrelated to resistance

Greater the voltage, the higher the current

Greater the resistance, the lower the current


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FACTORS DETERMINING SEVERITY OF

ELECTRICAL INJURY

Nature of the current

Voltage involved

If alternating current, frequency involved

Amount of current

Length of time the victim is in contact with thecurrent

Condition of the earth (dry or wet), if the earth ispart of the circuit

Resistance of the body

The path of the current through the body


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LOW VOLTAGE DEATH

Voltage less than 1.000

volts Cause of death not always

obvious

Direct contact betweenvictim and the electrical

circuit Death primarily due to

ventricular fibrillation

If low current but greatcontact time= death may

still occur but mechanismof death is by muscleparalysis with secondaryasphyxia

HIGH VOLTAGE DEATH

Voltage more than 1,000

volts

Direct contact notnecessary as current mayarc to victim

Electric arc can genertehigh temp. (4000C)

Death due to respiratoryarrest or electrothermalinjuries caused by heat

generated by current


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RESISTANCE & CURRENT FLOW

Since voltage is fairly constant, changes in

resistance becomes an important factor in

determining amount of current that will flow

through the body

Blood and body fluids offer the least

resistance


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Human skin provides the greatest degree of

resistance

Type of Skin Resistance (ohms)

Dry,calloused,thickened 1 million ohms

Dry, non-calloused 100,000

Moist 1,000Moist, thin 100


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Also dependent on

type of clothing

Rubber boots andgloves


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Current

(mA)

Effect on Body

1 Threshold of perception, tingle

5 Muscle tremor

15 Muscle contraction, w/c prevents releaseof line

40 Possible loss of consciousness

75-100 Ventricular fibrillation

2000

(2 Amps)

Ventricular arrest


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ELECTRICAL BURN

OF THE SKIN

LOW VOLTAGE

Electrical burns in about

50% of cases

If victim remains in contactwith the electrical source,

severe burns may be seen

Electrical burns may be

hidden (mouth)


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ELECTRICAL BURN

OF THE SKINHIGH VOLTAGE

Electrical burns are seenin virtually all cases

Burns produced may besevere with charring oftissue

Distinctive odor = burntcork

Multiple small pittedburns may occur ascurrent arcs across body

Flash burnslargeareas of the skin


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ELECTRICAL BURN


May cause explosive

injuries Loss of extremities

Rupture of organs

If burns produced by

contact: Fingertips or palms

Soles of the feet


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ELECTRICAL BURN


Typical burn

Chalky white or

yellow/tan with centralcrater and raised paleborder

May have focal, smallareas of blackening

May be surrounded by azone of erythema

Punctate to 1-2 cm


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Lightning strike

Virtually all discharges are negative

Direct current (1000 million volts or more)


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Lightning strike

Direct strike

Contact- contact with object hit by lightning

Side flash- bolt strikes an object then jumps tothe individual nearby

Ground current- electrical energy from the

bolt move towards the ground and results in

injuries


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Lightning strike


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Lightning strike


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Lightning strike

Arborescent marks

Lichtenberg bodies

Filigree burns


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Lightning strike

Cardiopulmonary arrest

Electrothermal trauma

Paralysis of the nervous system Complications of burns


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THERMAL & FIRE INJURY


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CLASSIFICATION OF BURNS

ACCORDING TO

DEPTH OF INJURY

FIRST DEGREE

Limited to superficial

epidermis

Erythema & edema

Blistering not present

Painful No scarring

Ex. Mild sun burn



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ACCORDING TO

DEPTH OF INJURY

SECOND DEGREE

Partial thickness burns

Involve all of epidermis &

some of dermis

Sparing of skin appendages

Blister

Senses intact, with someassociated pain

Heal without scarring

except in deep burns which

may scar


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ACCORDING TO

DEPTH OF INJURY THIRD DEGREE

Full thickness

Necrosis of all skinlayers including skinappendages

Burned area appearswhite

Sensation is lost Severe scarring


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ACCORDING TO

DEPTH OF INJURY FOURTH DEGREE

Charring injury

Incineration of tissues Complete destruction

of the skin and

subcutaneous tissue

Complete or partialcharring of the bone


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CHARRED BODIESCharring may: Produce large splits in the

skin or muscle Occur parallel to muscle

fibers

Not due to to antemortem

trauma

Pugilistic attitude

Flexion of the upper

extremities similar to a

boxer holding hands in

front of his face Flexures develop as body

cools, not a reflexion of

position of body prior to

burning


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CHARRED

BODIES

Charring may:

Complete absence of

fingers, toes andportions ofextremities

Heat fractures

heat epidural

form as the blood

boils out of the venoussinuses

Chocolate brown,spongy or crumbly

Located over frontal,temporal or parietalareas of brain


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CHARRED BODIES

May be charred on

outside but internal

organs are usually wellpreserved


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BURN SEVERITY FACTORS

INTENSITY OF THE HEAT

Ordinary house fires = less than 1200-1600 F

industrial fuel fires = greater than 1900-2100 F

DURATION OF EXPOSURE Skin exposed to heat for 2 hrs

Hyperemic without loss of epidermis

Skin exposed to heat for 3 hours

Complete epidermal necrosis occurs

Cremation1500 F for 1-1 hrs


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EXTENT AND PATTERN OF BURN


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FACTOR AFFECTING BURN SURVIVAL

AGE

DEGREE OF THE BURN

PERCENTAGE OF TOTAL BODY SURFACE AREA


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CLOTHING & BURNS

MATERIAL

Cotton fabrics

less protection

Ignite easily

Nylon, polyester, wool produce less severe burns

Ignite less readily

TYPE / DESIGN OF GARMENT

Close fitting clothes are safer than long loose garments(i.e. nightgowns)


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ACCORDING TO AGENT

FLAME BURNS

CONTACT BURNS

RADIANT BURNS

SCALDING BURNS

Immersion burns

Splash or spill burns

Steam burns

MICROWAVE BURNS


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ACCORDING TO AGENT FLAME BURNS

Due to direct contact

with a flame

Severity depends upon

the length of time the

flame is applied


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ACCORDING TO AGENT FLASH BURNS

Variant of flame burn

Caused by suddenignition or explosion of

fine particulate matter

or gas

Produces a uniform

burn (1stor 2nddegree)

of all exposed areas of

the skin, singes hair


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ACCORDING TO AGENT CONTACT BURNS

Occur when skin is in

contact with a hot

object such as hot iron

May have

configuration or shape

of hot object that was

applied to the skin


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ACCORDING TO AGENT RADIANT BURNS

Occur when skin is

exposed to heat waves

Contact with heat

source is not necessary

for a burn to occur

May produce blisters &

erythema

Prolonged exposure

may result in charring


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ACCORDING TO AGENT SCALDING BURNS

When the skin is

contacted by a hot

liquid

Water at 70 C

Produce 3rddegree

burns in about one

second of contact

Water at 55 C

Almost 25 seconds to

produce same burn


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ACCORDING TO AGENT IMMERSION BURNS

Accidental / homicidal

Homicidal example Child abuse

Immersion of child in

tub full of scalding

water

Burns with sparing ofknees, popliteal fossae

and inguinal regions


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ACCORDING TO AGENT SPLASH BURNS

Usually accidental

Caused by spilling hot liquid over the body STEAM BURNS

Usually accidental

Superheated vapor can cause severe injury to the mucosa

of the airway Massive laryngeal edema may occur


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ACCORDING TO AGENT MICROWAVE BURNS

Most are accidental

Occur as an individual reaches into a microwave which has notturned off completely or by ingestion of scalding hot liquid

heated in a microwave



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ACCORDING TO AGENT CHEMICAL BURNS

Strong acids and alkalis Phosphorus, phenols

Burns produced slowerthan by thermal agents

Extent of injury dependon:

The chemical agent

Strength orconcentration of agent

Duration of contact with

the agent


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ACCORDING TO AGENT Alkaline agents

Tend to cause moresevere injury than acid

agents Produce burns generally

have a pH greater than11.5

Frequent produce full

thickness injury Produce burns that

appear pale and feelleathery and slippery


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ACCORDING TO AGENT Acid agents

Produce only partial

thickness burns

May be accompanied

by erythema and

superficial erosion


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Death due to burn injury

Immediate death

Within minutes to hours of the injury

Delayed death Occur as result of numerous possible complications


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Death due to burn injury Immediate death may result

from

Neurogenic shock

Direct thermal injury

Large amount of fluidloss=hypovolemia = shock, acute

renal failure Inhalation injury

Soot in nares or mouth

Externsive thermal injury ofairway mucosa = mucosal

necrosis & edema =bronchospasm or upper airwayobstruction due to laryngealedema

Carbon monoxide poisoning


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Inhalation injury

Other noxious agents

Cyanide

Acrolein

Reactive aldehyde produced by burning wood & petroleum products

Injury by protein denaturation Hydrochloric acid

Due to combustion of plastsics, furnishings building components

Pulmonary edema may be delayed for 2-12 hours after exposure

Tolouene diisocyanate

Nitrogen dioxide

h d b


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Inhalation injury

Other noxious agents

Tolouene diisocyanate

Produced by burning polyurethane

May cause severe bronchospasm

Nitrogen dioxide

Produced in fires involving automobiles or agricultural wastes

Even brief exposure could cause broncho/larungeal spasm and

pulmonary edema

Chronic interstitial lung disease may be a late complicataion


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THANK YOU !

5 electrocution

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