Transcript PHEMO ELECTRICAL INJURIES

PREHOSPITAL EMERGENCY
MANAGEMENT OF
ELECTRICAL INJURIES
DEFINITION
An electrical injury is damage to the skin or
internal organs when a person comes into
direct contact with an electrical current.
Factors Determining Electrical Injury
Type of circuit
Resistance of tissues
Amperage
Voltage
Current pathway
Duration
Environmental factors
Body Tissue Resistance
Least
Intermediate
Most
Nerves
Blood
Mucous membranes
Muscle
Dry skin
Tendon
Fat
Bone
Symptoms
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Symptoms depend on many things, including the type and strength of
voltage, how long you were in contact with the electricity, how it moved
through your body, and your overall health.
Changes in alertness (consciousness)
Broken bones
Heart attack
Headache
Problems with swallowing, vision, or hearing
Irregular heartbeat
Muscle spasms and pain
Numbness or tingling
Breathing problems or lung failure
Seizures
Skin burns
LOW VOLTAGE ELECTRICAL
INJURY (UP TO 500 VOLTS)
Pathophysiology
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Tissue Necrosis or severe burns
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Cardiac Problems
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Muscle Spasm
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Oral Burn
Low Voltage Electrical Injury
HIGH VOLTAGE ELECTRICAL INJURY
Pathophysiology
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The pathway of current can be somewhat unpredictable,
but, in general, current passes from a point of entry
through the body to a grounded site, i.e. , a site of lower
resistance to flow compared with air, which is a poor
conductor.
Extremely high voltage sources usually exit in multiple
areas in an explosive fashion. Current passing from hand
to hand or hand to thorax has a high risk of producing
cardiac fibrillation compared to hand to foot passage.
Passage through the head is likely to cause an initial
respiratory arrest and subsequent severe neurologic
impairment.
HIGH VOLTAGE ELECTRICAL
INJURY
Common Complications –
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Ventricular Fibrillation
Muscle necrosis,
Other rhythm abnormalities
Fractures
Respiratory arrest
Hemolysis
Seizures/Coma
Renal Failure
Mental changes
Hemorrhage
Hypertension,
Limb loss
Retinal detachment,
Anemia
Cataract (delayed),
Paresis/paralysis and other neurotic (delayed)
HIGH VOLTAGE INJURIES
Pathway of Current
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The pathway of current can be somewhat
unpredictable, but, in general current passes
from a point of entry through the body to a
grounded site, i.e. , a site of lower resistance to
flow compared with air, which is a poor
conductor.
Extremely high voltage sources usually exit in
multiple areas in an explosive fashion.
Current passing from hand to hand or hand to
thorax has a high risk of producing cardiac
fibrillation compared to hand to foot passage.
Passage through the head is likely to cause an
initial respiratory arrest and subsequent severe
neurologic impairment.
MECHANISM OF ELECTRICAL
INJURY
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DIRECT CONTACT
ARC
FLASH
THERMAL
BLUNT TRAUMA
MECHANISM OF ELECTRICAL
INJURY
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Direct contact: Current passing directly through the body will heat the
tissue causing electrothermal burns, both to the surface of the skin as well as
deeper tissues, depending on their resistance. It will typically cause damage at
the source contact point and the ground contact point. Contact burns are shown
in the image below.
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Electrical arcs: Current sparks are formed between objects of different
electric potential that are not in direct contact with each other, most often a
highly charged source and a ground. The temperature of an electrical arc can
reach 2500-5000o C, resulting in deep thermal burns where it contacts the skin.
These are high-voltage injuries that may cause both thermal and flame burns in
addition to injury from direct current along the arc pathway.
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Flame: Ignition of clothing causes direct burns from flames. Both
electrothermal and arcing currents can ignite clothing.
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Flash: When heat from a nearby electrical arc causes thermal burns but
current does not actually enter the body, the result is a flash burn. Flash burns
may cover a large surface area of the body but are usually only partial
thickness.
Direct contact
FLASH BURNS
Electrical arcs are formed between areas of
different electrical potential that are not in direct
contact with one another. The charge needed to
create an electrical arc is usually very high, and
associated temperatures can reach 25005000°C.
FALLS
High Voltage Is More Likely to
Kill Than Low Voltage-A MYTH
A momentary dose of high
voltage electricity is not
necessarily fatal.
Low voltage is just as likely to
kill as high voltage.
TYPE OF CIRCUIT
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High-voltage direct current (DC) tends to cause a
single muscle spasm, often throwing the victim from
the source, resulting in a shorter duration of
exposure but increasing the likelihood of traumatic
blunt injury.
Alternating current (AC) is said to be about three
times more dangerous than direct current of the
same voltage, because continuous muscle
contraction, or tetany, occurs when the muscle fibers
are stimulated at between 40 and 110 times per
second. The frequency of electrical transmission
used in the United States is 60 Hz. Tetany occurs
even at very low amperages.
FACTORS DETERMINING
SEVERITY
JOULE’S LAW:
Power (watts) = Energy (Joules)
time
=Vxi
2
=i xR
Mechanisms of Injury
 Direct
effect of electrical current
 Thermal burns
 Mechanical Trauma
 Post-trauma sequelae
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BURNS
This definition describes a burn injury as
damage to the skin and underlying tissues
such as the subcutaneous tissues, muscle
and even bone in the case of electrical
injury. Burn injuries can be caused by
heat (thermal injury), chemicals or by
contact with electricity.
Primary Complications and Causes of
Death in Electrical Injuries
Cardiopulmonary arrest
Overwhelming injuries
Cardiac arrhythmias
Hypoxia and electrolytes
Intracranial injuries
Myoglobinuric renal failure
Abdominal injuries
Sepsis
Tetanus
Iatrogenic
Suicide
SCENE SAFETY
Create a safe environment for bystanders and
rescuers.
The victim may still be part of a live circuit.
Therefore, turn off the power source before
approaching the victim or the surrounding area.
Particularly for high-voltage injuries, the safest
approach is to involve authorized personnel, such
as the local power company, in disconnecting the
power source.
CHECK RESPONSIVENESS AND
CALL FOR HELP-1099,102,100
PRIMARY SURVEY
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Immediately life threatening conditions are identified
and emergency management begun.
A. Airway maintenance with cervical spine control
B. Breathing and ventilation
C. Circulation with haemorrhage control
D. Disability - neurological status
E. Exposure + environmental control
F. Fluid resuscitation proportional to burn size
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Airway Maintenance With Cervical Spine Control
Clear the airway of foreign material and open
the airway with chin lift/jaw thrust. Keep
movement of the cervical spine to a minimum
and never hyperflex or hyperextend the head
and neck.
Injuries above the clavicle, such as facial
injuries or unconsciousness, are often
associated with cervical fractures.
B. Breathing and Ventilation
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Expose the chest and ensure that chest
expansion is adequate and equal.
Ventilate –Mouth to mouth or Mouth to Mask.
Always provide supplemental oxygen.
Carbon monoxide poisoning may give a
cherry pink, non breathing patient.
C. Circulation With Hemorrhage Control
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Check the pulse - is it strong or weak?
Capillary blanch test - normal return is two
seconds. Longer indicates hypovolaemia.
Stop bleeding with direct pressure.
Mental obtundation occurs with loss of 50%
of blood volume.
Pallor occurs with 30% loss of blood volume.
D. Disability: Neurological Status
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Establish level of consciousness:
A - Alert
V - Response to Vocal stimuli
P - Responds to Painful stimuli
U - Unresponsive
Examine the pupillary response to light. They should
be brisk and equal.
Be aware that hypoxaemia and shock can cause
restlessness and decreased level of consciousness.
E. Exposure With Environmental Control
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Remove all clothing and jewellery
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Area burned is estimated by using the Rule of
Nines or a burn body chart.
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Keep the patient warm
Depth of burn
Dressing
 Cleaning the wound- saline, soap and water, or
chlorhexidine 0.1% solution
 Dressing – occlusive dressings with topical cream-
SSD, Soframycin
 Elevation-Elevation of the burned part is useful during
initial treatment as it tends to limit swelling.
Special areas
Respiratory burns (thermal burns of the upper airway)
are often associated with rapidly accumulating swelling
and early intubation is necessary.
Burns of the perineum require early urinary
catheterisation in order to prevent contamination.
Head and neck burns should have elevation of the
head to limit upper airway swelling.
History Of The Event
• How did the accident occur?
• How long ago did the accident occur?
• Was there loss of consciousness and for how long?
• Is there amnesia for the event?
• Was there any associated trauma?
• Did cardiac arrest occur or was any dysrhythmia
recorded?
History
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Determine if injury was low-voltage ( 600V) or high-voltage (
600V).
Voltage is one parameter in electrical injury that can be reliably
estimated most of the time from the scene.
High-voltage injuries are generally more serious and more likely
to involve internal damage. For this reason, if a high-voltage
injury is established or suspected, more aggressive fluid
resuscitation is required, and triage of the patient may proceed
differently than in low-voltage patients.
HISTORY
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If possible, determine the type of electrical source, alternating
current (AC) vs. direct current (DC).
A history of DC exposure generally involves a single muscle
spasm that throws the victim from the source.The victim has a
shorter duration of electrical exposure but increased risk of
traumatic blunt injury.
A history of AC exposure generally involves a “no let go”
response with tetanic (continuous) muscle contractions, and
hence, prolonged exposure to current. Therefore, these injuries
are generally much more severe than injuries due to DC and
carry high risk of extensive tissue destruction and/or cardiac
abnormalities.
HISTORY
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If possible, determine the mechanism of injury, i.e., direct vs.
indirect contact. Knowing the mechanism can help in directing
management and/or offering a prognosis.
If the injury was a flash or thermal burn as an indirect result of
electric current, internal injuries are unlikely.
If the burn injury resulted from an electrical arc (indirect but
striking the body at destructively high temperatures) or from
direct contact, the risk of internal injury is high, and greater
precautions should be taken.Current flows easily through nerve,
blood, and muscle, creating electrical disruption, whereas tissues
with higher electrical resistance, such as bone, tendon, and fat,
will more likely develop damage from thermal burn injury when
exposed to significant electrical current.
HISTORY
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The patient after an electrical injury is often unable
to give a good history, either because of the
severity of injury and accompanying shock and
hypoxia or because of unconsciousness or
confusion that often accompanies less severe in
juries.
History from bystanders regarding the type of
electrical source, duration of contact,
environmental factors at the scene, can be helpful.
Information on prior medical problems, medication
history, tetanus immunization status, and allergies
should be sought.
Rule of nines
LOW VOLTAGE INJURIES
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Evaluation of low-voltage injuries should include a good history
because injury that initially appears to be from a low-voltage
source may turn out to have been caused by a discharge from a
capacitor (as in the repair of televisions and convection or
microwave ovens) or other high-energy source. Although burns
from low-voltage sources are usually less severe than those
from high-voltage sources ,patients may still complain of
paresthesias for an extended period experience cardiac
arrhythmias or develop cataracts if the shock occurs close to the
face or head.
VASCULAR INJURY
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Vascular damage from the electrical energy may be evident early
or late Because the arteries are a high-flow system heat may be
dissipated fairly well and result in little apparent initial damage
but thrombosis with subsequent thrombosis or rupture .Pulses
and capillary refill should be assessed and documented in all
extremities, and neurovascular checks should be
repeated frequently.
EXTREMITY INJURY
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In high-voltage injuries muscle necrosis can extend
to sites distant from the observed skin injury and
compartment syndromes can occur secondary to
vascular ischemia and muscle edema. Although it is
preferable to stabilize the patient prior to transfer to
the operating room this is not always possible.
Extremities that have teen burned should be
splinted in functional position to minimize edema
and contracture formation. electrical injury have
been reported.
CUTANEOUS INJURY
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The most common sites of contact for the current include the hands and
the skull. The most common areas of ground are the heels. There may
be multiple contact and ground points.
Because high-voltage current often flows internally and can create
massive muscle damage one should not attempt to predict the amount
of underlying tissue damage from the amount of cutaneous involvement
or use the rule of nines for calculating fluid resuscitation. Cutaneous
burns should be covered with antibiotic dressings .
Electrical burns are especially prone to tetanus infection and patients
should receive tetanus toxoid and tetanus immune globulin on the basis
of their immunization history.
A special type of burn from low-voltage injuries is the mouth burns that
occur secondary to sucking on household electrical extension cords
and are the most common electrical injury seen in children under 4
years of age.
HEAD AND NECK
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The head is a common point of contact for high volt-injuries and
the patient may exhibit burns as well as neurologic damage.
Cataracts develop in approximately 6 percent of cases of highvoltage injuries and should be suspected whenever electrical
injury has occurred in the vicinity of the head.Although cataracts
may be present initially or develop shortly after the accident. they
more typically begin to appear months after the injury.
Cervical spine injury may be caused by a fall or being thrown in
either type of injury.
DIFFERENTIAL DIAGNOSIS
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Electrical injuries are usually self-evident from history and
physical surroundings, except in the case of bathtub accidents,
where no burns occur, or of foul play. It is necessary to attempt to
differentiate between mechanisms of burn injury because flash
burns have a much better prognosis than arc or conductive
burns. Injuries from blunt trauma and falls may also be present.
The differential diagnosis for lightning injuries is more complex,
often because the incident is unobserved . It includes the
differential for unconsciousness, paralysis, or disorientation from
a number of causes. Evidence- of a thunderstorm or a witness to
the lightning strike may not be available. The presence of typical
burn patterns, when present, may be helpful.
Post-trauma sequelae
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Crush injury syndrome (rhabdomyolysis,
myoglobinuria)
Multi-organ ischemic injury Hypovolemic
shock
Iatrogenic injuries from acute resuscitation
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Abdominal compartment syndrome
ARDS
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Disposition
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Hospitalization for in-patient observation or
treatment of electrical injury victims
Hospitalization for cardiac monitoring is
suggested.
Hospitalization also is suggested for patients
with high-voltage exposure, significant burns,
myoglobinuria/myoglobinemia or suspicion of deep
tissue damage.
Points to remember
1. Avoid injury to those rendering assistance.
2. Treat cardiac and respiratory arrest.
3. Assess and manage associated trauma.
4. Continuous cardiac monitoring for 24 hours for
significant injuries.
5. All electrical burns should be admitted to a burn
centre for definitive treatment.
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Electrical injuries are preventable
Always use proper care when working with
electricity
Do not take short cuts
Dr Ritu Saxena
CMO,
Deptt of Accident&
Emergency,
Lok Nayak Hospital,
New Delhi.