an introduction to electrical burn for medical students and residents - easy to understand

1. Introduction to
Electrical Injury
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2. • Electrical burns: a small part of major burn
centers  5-7%
• Most devastating of thermal injuries on size-
to-size basis: involving both skin and deeper
tissue
• Most frequent cause of amputation in burn
service

3. PATHOPHYSIOLOGY

4. • Exact pathophysiology is unknown
• Numerous variables cannot be measured
when an electrical currents pass through the
tissue
• With high voltage (≥1000V), most of injury is
thermal and resulting in coagulation necrosis
• The injury can be explained by Ohm’s Law

5. I = V/R
P = I2R
I = current, in amperes (A)
V = potential, in volts (V)
R = resistance, in ohms (Ω)
P = power, in Joules (J)

6. Factors Determining Severity
• Type of circuit
• Duration
• Resistance of tissue
• Voltage
• Amperage
• Pathway of current

7. Type of Circuit
• Direct (DC) or alternating current (AC)
• DC: Cause single spasm and throw the victim
from the source  increased traumatic blunt
injury
• AC: cause continuous muscle contraction or
tetany  no-let-go phenomenon and creating
potential for continually increasing severity
– Occur when both flexor and extensor are stimulated
but flexor is stronger making victim unable to let go
voluntarily

8. Duration of Contact
• Longer duration with high-voltage current 
greater tissue destruction

9. Tissue Resistance
• The word entrance and exit  replaced by
contact points
• The higher resistance, the greater
transformation electrical injury to thermal
injury
• Least: nerve, blood, mucous membrane,
muscle
• Intermediate: dry skin
• Most: tendon, fat, bone

10. Tissue Resistance: skin
• Primary resistor
• Thick and harden skin = greater resistance
• Sweating: decrease resistance

11. Voltage
• Low voltage < 1000V
• High voltage ≥ 1000V
• Thailand domestic wiring 220V
• Higher voltage, higher morbidity

12. Amperage
• P = I2R and I = V/R
• More amperage, more heat
• The voltage of source is often known but not
for resistance
• Physical effects vary with different amperage

13. Price TG and Cooper MA. Electrical and lightning injuries: in Rosen’s emergency
medicine. Access via PDF

14. Pathway
• Where the current passes: between the
contact points

15. MECHANISMS OF INJURY

16. • Primary is burn
• Secondary: fall or being thrown from electrical
source by muscle contractioin
• 4 types of electrical burn
– Direct contact: electrothermal heating
– indirect contact: arc, flame

17. • Electrical arc:
– A current spark between 2 objects differing
potential not contact to each other
– Most destructive indirect injury
– Usually highly charged source and a ground
– Temperature of the arc reaches 2500oC
• Flame: result from ignition of clothing

18. Heart
• Most serious: cardiac arrest
• Dysrhythmia: AF
• ECG abnormality: non-specific ST-T change
• Can occur both low and high voltage
• ECG monitoring is mandatory in patients with
ECG abnormality

19. Respiratory
• May result from:
– Tetanic contraction of thoracic musculature
– Injury to respiratory control center of CNS
– Combined cardiopulmonary arrest secondary to
asystole or VF
– Blunt chest trauma from being thrown

20. Cutaneous
• Low voltage: small, well-demarcated contact
burns
• High voltage: painless, depressed, yellow-gray,
charred craters with central necrosis, or may
spare the skin surface but damage deeper
tissue

21. Czuczman AD. Electrical injuries: a review for the emergency physician. 2009;11(10):1-21

22. Muscle
• Coagulation necrosis  becoming edematous
and necrotic 
• Myoglobinuria, rhabdomyolysis, and acute
renal failure
• Compartment syndrome

23. Myoglobinuria
• Dark urine, mahogany-colored
• Significant muscle damage with potentially
ischemia
• UA: urine dipstick +ve for blood with few RBC
• Risk of acute renal failure
• Elevated CPK

24. Compartment Syndrome
• High-voltage injury: risk for developing
compartment syndrome in first 48 hours
• Damaged and swelling muscle  increased
pressure within fascia
• CK level: associated with extent of muscle
damage

25. Vascular
• Greatest damage to media layer  delayed
aneurysm formation
• Intima: thrombosis and occlusion
• Most severe in small muscle branch: tissue
necrosis
• Any vascular injury can cause compartment
syndrome

26. Neurologic
• PNS > CNS in electrical injuries
• Most common CNS symptom = loss conscious
• Others: peripheral neuropathy, transient
paralysis, spinal cord damage

27. Gastrointestinal injuries
• Suspected in burn at abdominal wall
• History of fall, blast, blunt trauma

28. Oral Burn
• Children who put a power cord in the mouth
• Labial artery bleeding: occur up to 2 weeks
after injury

29. • Eye injury: cataracts
• Auditory system: path of current may be
damaged

30. Czuczman AD. Electrical injuries: a review for the emergency physician. 2009;11(10):1-21.

31. TREATMENT

32. Prehospital Care
• Secure the scene
• Ensure that the power source has been turned
off
• CPR + follow ACLS
• Protect cervical spine and splint fracture
• Close burn wound with clean dry dressing

33. ER care
• Follow ACLS and ATLS
• Resuscitation
• Complete lab
• Remove constricting objects
• ECG

34. Fluid Resuscitation
• Parkland formula: only rough starting point
• In absence of gross myo/hemoglobinuria, goal
is to maintain v/s: 0.5 ml/kg/hr
• In children:
– 10% burn: resuscitation
– Fluid of choice: LRS
– <2years: 5%DLR
– Maintenance fluid: 5%DN/2

35. ECG monitoring
Czuczman AD. Electrical injuries: a review for the emergency physician. 2009;11(10):1-21.

36. ECG monitoring
• Duration: 24-48 hours
• Low voltage + normal ECG: can be discharged
• Utility of CK-MB:
– Not reliable due to other muscle injury
– Use of troponin: insufficient data

37. Treatment of Myoglobinuria
• Monitoring urine for myoglobin and serum for
CPK
• Maintain a urine output “double” goal rate: 1
– 1.5 ml/kg/hr
• Fluid should be NSS 1000 ml + NaHCO3 50
mEq
• pH of ABG: > 7.45
• Mannitol: 25 g, then 12.5 g/h

38. Compartment Syndrome
• 4 compartment fasciotomies for lower
extremities
• Anterior and posterior fasciotomies with
carpal tunnel release for upper extremities
• Primary amputations are not generally
performed

40. Wound Care
• Dressing wound with sulfamylon on the thick
eschar
• SSD: for microbial control
• Biologic dressing on more superficial area
• Remove necrotic tissue and reevaluate q2-
3days
• Tetanus immunization

41. Pain Management
• Acute pain: opioids and paracetamol
• Rehabilitation phase: NSAIDs, antidepressant,
massage therapy, cognitive behavioral therapy

42. References
ชัยรัตน์ บุรุษพัฒน์. Electrical injuries: principle and management. เวชสารแพทย์
ทหารบก.2011;4:207-10.
Herndon DN. Total burn care. 4th ed. China: Elsevier, 2012.
Arnoldo B, Klein M, Gibran NS. Practice guidelines for the management of
electrical injuries. Journal of burn care and research. 2006;27(4):439-46.
Czuczman AD. Electrical injuries: a review for the emergency physician.
2009;11(10):1-21.
Fish RM. Electric injury, part II: specific injuries. The journal of emergency
medicine. 2000;18(1):27-34.

43. References
Price TG and Cooper MA. Electrical and lightning injuries: in Rosen’s
emergency medicine. Access via PDF
Guidelines for paediatric burn resuscitation