ELECTRICAL INJURY

1. ELECTRICAL INJURY

2. Definition
• An electrical injury is damage to the skin or
internal organs when a person comes into
direct contact with an electrical current

3. Epidemiology
• Electrical injuries –
• 1000 deaths per year
• 3000 admissions to specialized burn centers
per year.
• Lightning injury –
• 50-300 deaths per year

4. Etiology
• 20% of all electrical injuries- in children
• At home, with extension cords (60-70%) and wall
outlets (10-15%)
• Adults: 4th leading cause of work-related
traumatic death
• 50% of these occupational electrocutions result
from power line contact (5-6% of all work-related
deaths), and 25% result from using electrical
tools or machines
• Male to female ratio is 17:1

5. Pathophysiology

6. 3 major mechanisms of electricity-
induced injury:
1. Electrical energy: direct tissue damage,
altering cell membrane resting potential,
muscle tetany.
2. Thermal energy: massive tissue destruction
and coagulative necrosis.
3. Mechanical injury: direct trauma resulting
from falls or violent muscle contraction

7. Four classes of electrical injuries
1. True electrical injuries - The person becomes part of
the electrical circuit and has an entrance and exit site
2. Flash injuries - Superficial burns caused by arcs that
burn the skin; no electrical energy travels through the
skin
3. Flame injuries - Caused by ignition of the persons
clothing by arc; electricity may or may not travel
through the person’s body
4. Lightning injuries - A unique type of injury that occurs
at extremely high voltages for the shortest duration;
the majority of electrical flow occurs over the body

9. Direct contact

10. 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 2500-5000°C
Flash burn

11. Classification
• Low Voltage High Voltage

12. Factors Determining Electrical Injury
1. Type of circuit
2. Resistance of tissues
3. Amperage
4. Voltage
5. Current pathway
6. Duration
7. Environmental factors
8. Individual susceptibility

13. Type of circuit
AC
• tetanic muscle contraction
• diaphragm and intercostal
muscles can result in
respiratory arrest
• ventricular fibrillation
• AC more dangerous than DC
DC
• single violent muscle
contraction, often thrusting
the victim away from the
source

14. Body Tissue Resistance
Least Nerves
Blood
Mucous membranes
Muscle
Intermediate Dry skin
Tendon
Fat
Most Bone

15. 1. Ohm’s Law:
Current (I) = Voltage (E) / Resistance (R)
2. Joules law:
Power (J-Joule) = I2 (Current) × R (Resistance)
Power (J) = I (Current) X V (Potential difference)

16. (1,000 milliamperes = 1 amp; therefore, 15,000 milliamperes = 15 amp circuit)
Current Reaction
Below 1 milliampere Generally not perceptible
1 milliampere Faint tingle
5 milliampere Slight shock felt; not painful but disturbing. Average individual
can let go. Strong involuntary reactions can lead to other injuries
6-25 milliamperes (women) Painful shock, loss of muscular control
9-30 milliamperes (men) The freezing current or “let-go” range. Individual cannot let go,
but can be thrown away from the circuit if extensor muscles are
stimulated.
50-150 milliampres Extreme pain, respiratory arrest, severe muscular contractions.
Death is possible.
1,000-4,300 milliamperes Rhythmic pumping action of the heart ceases. Muscular
contraction and nerve damage occur; death likely
10,000 milliamperes Cardiac arrest, severe burns; death probable

17. Current pathway
1. Vertical: higher incidence of complications
2. Hand to hand pathway
3. Below symphysis: stradle pathway

18. Cardiovascular involvement
1. Any cardiac arrhythmia can be precipitated
2. Direct myocardial injury
• High voltage or DC current usually causes
asystole, and AC current usually causes
ventricular fibrillation
• Ventricular fibrillation- most common cause of
death (60% of patients in whom the current
pathway goes from one hand to the other
hand)

19. Respiratory involvement
• Tetany of respiratory
muscles
• Brain stem injury
• May induce hypoxia,
acidosis -> cardiac
arrest

20. Nervous system
• Direct heat
• Disruption of sodium-potassium-ATPase pump
operating at −90 millivolts direct current
• Electroporation of cellular membranes -
Breakdown of cell membranes

21. Vascular injures
• Large arteries- medial necrosis, aneurysms
• Small vessels- intimal injuries, coagulation
necrosis
• Secondary to compartment syndrome

22. Limb injuries
• Severity of injury is inversely proportional to
the cross-sectional area of tissue
• Most severe injuries are seen at the wrists and
ankles, with decreasing severity proximally.
• In hand-foot current flow, 30% of the
resistance is in the ankle and 25% in the wrist

24. Renal involvement
• Acute renal failure
• Acute tubular necrosis
• Secondary hypovolemia from third spacing
and huge volume shift
• Rhabdomyolysis that results from massive
tissue necrosis can also cause pigment-
induced renal failure

26. Management

27. ATLS protocol
• 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

28. Resuscitation
• Burn resuscitation formulas based on body
surface area burned inaccurate
• In absence of gross myo/hemoglobinuria, goal
of resuscitation is to maintain normal vital
signs and a urine output of 30–50 mL/h with
Ringer’s lactate (rate adjusted on an hourly
basis)

29. Myoglobinuria
• Presence of pigmented (darker than light pink)
urine
• Myoglobin and hemoglobin pigments
• Rapid, osmotic diuresis with initial alkalinization
to minimize pigment precipitation in renal
tubules
• Loop diuretics are not as efficient as mannitol.
• Required U/O very high for several hours
following injury, followed by significant reduction
(venous return from the injured part to the
central circulation is thrombosed)

30. • Two ampules of mannitol (25 g) given IV push
• Two ampules of sodium bicarbonate, also given
IV push.
• Ringer’s lactate is administered at a rate sufficient
to grossly clear the urine of pigment.

32. Electrocardiographic monitoring
Indications for cardiac monitoring
• Documented cardiac arrest
• Cardiac arrhythmia on transport or in ER
• Abnormal EKG in ER (other than sinus brady-
or tachycardia)
• Burn size or patient age would require
monitoring

33. • Most common abnormalities seen on an
electrocardiogram (ECG) are sinus tachycardia,
nonspecific ST- and T-wave changes, heart
blocks, and prolongation of the QT interval
• Creatine kinase (CK) and MBcreatine kinase
(MB-CK) levels are poor indicators of
myocardial injury in the absence of ECG
finding of myocardial damage

34. Wound care
• Cleaning the wound- saline, soap and water,
or chlorhexidine 0.1% solution
• Local burn care is performed using mafenide
acetate (Sulfamylon) on the thick eschar of the
contact points (excellent penetration).
• Silver sulfadiazine is used for microbial control
on the deep flash/flame components
• Biologic dressing used on more superficial
areas
• Elevation- to limit swelling

35. • Surgical excision begun 2–3 days postburn
• Obviously necrotic tissue removed, while tissues
of questionable viability are retained and re-
evaluated every 2–3 days until wound closure
• Conservative course of tissue removal and wound
closure with a combination of skin grafts and/or
flaps
• Ongoing program of physical therapy and
functional splinting

37. Accurate predictors of tissue damage
1. Radionuclide scanning with xenon-133
2. Technetium pyrophosphate.
3. Gadolinium-enhanced MR imaging

38. Scalp burn
• Sparing galea:-
– Excision and skin grafting directly onto the galea
• Penetrate outer table of skull or deeper:-
– Removing dead bone with an osteotome or a
dental type burr.
– Drilling multiple holes in a close set pattern, deep
enough to cause bleeding from viable cancellous
bone
(patient’s advanced age or large burn size precludes
more aggressive approaches to wound closure)

39. – Rotation scalp flap(s) over the burned area. Split-
thickness skin grafts over donor defect.
This provides rapid closure and is associated with
minimal morbidity
Skin expansion of the hair-bearing area can be
performed 12–18 months
– Larger scalp defects are closed with free flaps

41. Chest wall injuries
• thoracic injury to the deep structures phrenic
nerve and direct thermal injury to the heart
• present special closure problems (adjacent or
remote soft tissue flaps) for coverage of
exposed bone and cartilage.
• Costal chondritis is the most frequent
complication of deep chest wall burns
requiring multiple debridements

42. Abdominal wounds
• internal injuries both directly under contact
points and remotely as result of late ischemic
necrosis
• Patients must be frequently evaluated for
changes in their abdominal examination
and/or feeding tolerance.
• Deterioration mandates laparotomy.
• Repair of large abdominal wall wounds

43. Oral cavity
• Younger children
• only the oral
commissure are initially
treated very
conservatively
• most serious
complication is
bleeding from the labial
artery (10–14 days after
injury)

44. • Gentle stretching and the use of oral splints
give good cosmetic and functional results in
most patients
• Severe mircostomia is corrected by mucosal
advancement flaps.
• Burns of the mid-portions of mouth heal very
poorly and require a much more aggressive
surgical approach with carefully planned
reconstruction

46. Compartment syndrome
• First 48 hours post injury in high voltage injury
• Damaged muscle, swelling within the investing
fascia of the extremity
• Loss of pulses is one of the last signs
• Serial examinations of the affected extremities
or repeated measurements of compartment
pressures

47. Indications for fasciotomies
• clinical signs of compartment syndrome,
• Progressive nerve dysfunction
• failure of resuscitation with other patients
undergoing exploration
• aggressive debridement on the third to fifth
postburn day

48. Prevention of electrical injuries
• Do’s and Don’ts of electrical safety
• House should be checked to insure that they
are wired correctly.
• What are some signals that there may be a
problem with inadequate wiring?
• How are electrical cords misused?

49. • What are some safety principles regarding the
use of electrical appliances?
• Precautions for outdoors?

51. Injury Prevention for lightning
• If you are outside, what are some safety
measures?
– Do not stand under a natural lightning rod such
as a tall tree in an open, isolated area.
• Avoid projecting from the surrounding landscape,
e.g. open field, hilltop, on the beach.
• Get out of and away from open water.
• Get away from tractors and other metal farm
equipment.

52. • Get off and away from motorcycles, scooters, golf cart,
and bicycles. Put down the golf clubs -- even the “1”
iron!
• Stay away from metal pathways which could carry the
electricity to you, e.g. wire fences, clotheslines, metal
pipes.
• In a wooded area seek shelter in a low area under a
thick growth of small trees.
• In open areas, seek a low place such as a ravine or
valley.
• If stuck in an open area and you feel your hair stand on
end, drop to your knees and crouch very low. Do not
lie flat on the ground