Electrical injuries account for around 3% of burn injuries and can be fatal. The extent of injury depends on factors like current, voltage, resistance, and duration of contact. High resistance tissues like bone are prone to deep burns while low resistance tissues conduct current. Direct effects can cause cardiac, neurological and respiratory issues. Thermal burns result from the conversion of current to heat. Management involves ABCs and monitoring for complications across organ systems like compartment syndrome and rhabdomyolysis. Prognosis depends on severity and development of multi-organ failure.

1. Electrical Injuries
Abdalmohsen Ababtain
Emergency Resident
Saudi Board for Emergency Medicine
20th April 2013

2. Bob! You fool … don’t plug that in!!!!

3. Objectives
 Epidemiology
 Factors Determining Electrical Injury
 Mechanisms of injury
 Associated injuries
 Management
 Prognosis

4. Epidemiology:
 Account for ~ 3% all burn-related injuries
 Estimated 3,000 annual admits to burn units
 ~ 1/3 fatal - about 1,000 US deaths annually
 Bimodal distribution
◦ ~1/3 children <6 yrs (electric cords & wall
outlets)
◦ ~2/3 miners, construction, & electrical
workers
◦ Common cause occupational deaths
 Lightning responsible for ~300 injuries, 100
deaths

5. Physics 101
 Ohm’s Law :
 I (Current) = V (Voltage) / R
(Resistance)
 Example = Grasp 120V source, with
1000Ohms resistance = 120mAmps

6.  Joule’s Law
Energy = I2 x R x time
 Electrical energy will be converted to
heat
 Heat causes the most tissue damage

7. What’s the Fastest Legal Street
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 Base Price $2,400,000

9. Factors Determining Electrical
Injury
 Type of circuit
 Resistance of tissues
 Amperage (Current)
 Duration
 Voltage
 Pathway of current

10. Type of circuit
 Either direct current (DC) or
alternating current (AC).
 High-voltage DC contact tends to
cause a single muscle spasm, often
throwing the victim from the source
 AC exposure to the same voltage
tends to be three times more
dangerous than DC.

11. Resistance
 Resistance is the tendency of a
material to resist the flow of electric
current; it is specific for a given tissue,
depending on its moisture content,
temperature, and other physical
properties.
 The higher the resistance, the greater
the potential for transformation of
electrical energy to thermal energy.

12.  Nerves, muscle and blood vessels,
because of their high electrolyte and
water content, have a low resistance
and are good conductors.
 Bone, tendon, and fat, which all
contain a large amount of inert matrix,
have a very high resistance and tend
to heat up and coagulate rather than
transmit current.
 The other tissues of the body are

13. Current
 Current, expressed in amperes, is a
measure of the amount of energy that
flows through an object
 Amperage is dependent on the source
voltage and the resistance of the
conductor. (Remember I=V/R)
 The voltage of the source is known but
the resistance varies
 The physical effect vary with different
amperage.

14.  "let go" current
• The maximum current at which a person
can grasp the current and then release it
before muscle tetany makes letting go
impossible.

15. Duration of contact
 The longer the duration of contact with
high-voltage current, the greater the
electro thermal heating and degree of
tissue destruction.
With lightening injury The extremely
short duration and extraordinarily high
voltage and amperage of lightning
both result in a very short flow of
current internally, with little, if any, skin
breakdown and almost immediate
flashover of current around the body.

16. Voltage
 Voltage is a measure of the difference
in electrical potential between two
points and is determined by the
electrical source. Electrical injuries are
conventionally divided into high or low
voltage using 500 or 1000 V as the
most common cutpoint.
The higher the voltage the more is
tissue distraction

17. Pathway
 The pathway that a current takes
determines the tissues at risk, the type
of injury seen, and the degree of
conversion of electrical energy to heat.
 Heart: Dysrhythmias and myocardial
damage
 Brain: Seizures, and paralysis.
 Eyes: Cataracts

18. Mechanisms of Injury
 Direct effect of electrical current
 Thermal burns (conversion I to E)
 Mechanical Trauma
 Post-trauma sequelae

19. Direct effects of current
 In general, type & extent of injury depends on
current intensity (amps) (I = V/R)
 Cardiac, neurologic and respiratory systems
most susceptible to direct effects
 Skin is the resistor most effecting severity of
injury
◦ Wet skin has lower R (~1K ohm) vs. dry or
thick skin (>100K ohm), resulting in greater
current flow

20. Thermal (Burn) Injuries
 Heat (E) = IVT
 Type & extent of injury depends on current
intensity (I)
 R varies significantly between tissues
◦ Tissues with high R (e.g., bone), generate
more heat, resulting in osteonecrosis and
deep tissue periosteal burns
◦ Skin also has high R, thus entry/exit wounds
◦ Decreasing R (e.g., wet skin) results in lower
thermal injury, but higher current
conductance
 Coagulation of muscle, fat, vessels

21. Mechanical Trauma
 Trauma can result from fall or muscle
contraction
 Classic example is shock wave of lightning
causing blast injuries
 Even at low V, tetanic muscle contraction
can result in bone fx
◦ Cord injury can result from severe muscle
contraction, w/o any external signs of
trauma
 Can result in vascular compromise
◦ Acute hypotension should always prompt
search for thoracic or intra-abdominal

22. Post-trauma sequelae
 Crush injury syndrome (rhabdomyolysis,
myoglobinuria)
 Multi-organ ischemic injury 2o to vascular
coagulation or dissection
 Hypovolemic shock 2o to massive 3rd
spacing
 Iatrogenic injuries from acute resuscitation
◦ Abdominal compartment syndrome
◦ ARDS

26. Lichtenberg Figures
 Rare pathognomonic
“flower-like” branching
skin lesions in persons
struck by lightning
 Caused by “flashover”
effect of non-penetrating
current
 Rapidly fade, not
typically serious

27. Management I
 Standard ABCDEs of any major trauma
 Pulmonary
◦ Low threshold for intubation, as respiratory
failure common
 Cardiac
◦ Serial monitoring if high V, abnormal ECG,
LOC, respiratory arrest, or PMH of CV
dysfunction
 Neuro
◦ C-spine and log-roll precautions; CT head &
spine often warranted
◦ Thorough serial neurological exams, as
vessel coagulation can result in late

28. Management II
 Musculoskeletal
◦ Thorough evaluation for fractures
◦ Serial evaluations of limbs for compartment
syndrome requiring emergent decompression
◦ Even in absence of compartment syndrome,
persistent aciduria or myoglobinuria may require
limb amputation
 Skin
◦ Early debridement and later reconstruction
◦ Antibiotic prophylaxis (controversial)
 Renal
◦ Fluid resuscitation key, as 3rd spacing common &
myoglobinuria 2o/2 rhabdomyolysis can cause ARF

29. Management III
 GI
◦ Ulcer prophylaxis, as gastric ulcers
(Curling’s ulcers) can develop
◦ Ileus uncommon, but should prompt
evaluation for other injury
 Serial evaluation of liver, pancreatic, & renal
function for traumatic/anoxic/ischemic injury
 Judicious management of fluid and
electrolytes to avoid acidosis and
compartment syndromes

30.  Admission:
 In contact >600V
 Symptoms (Chest Pain, Palpitation, LOC,
confusion, weakness, dyspnea, abdominal
pain)
 Signs (weakness, burns with subcutaneous
damage, vascular compromise)
 Ancillary changes (ECG, CK,
myoglobinuria)
 Cardiac monitoring: If ECG abnormal
 No Admission:
 Household voltage injury 100-220V in adult
 Negligible risk for delayed arrhythmias
 Asymptomatic, normal ECG and normal

31. Prognosis
 Highly variable, depending on severity of
both initial injury and subsequent
complications
 High morbidity/mortality in patients with
multisystem organ failure
 Advances in surgical interventions (early
excision, fasciotomy, skin grafts, etc…)
have improved

33. References
 DM Mozingo & BA Pruitt. 1998. Electric Injury. in Fundamentals
of Surgery, 1st ed, JE Niederhuber, pp 194-195.
 DS Pinto & PF Clardy. 2007. Environmental electric injuries. Up-
to-Date, accessed 06/01/2007.
 TN Pham & NS Gibran. 2007. Thermal & Electrical Injuries.
Surg Clin N Am 87:185-206.
 AC Koumbourlis. 2002. Electrical Injuries. Crit Care Med
30:S424-S430.
 C Spies & RG Trohman. 2006. Electrocution & Life-Threatening
Electrical Injuries. Ann Intern Med 145:531-537.