Electrical injury

1. QUIZ
• Answers
1. C
2. B
3. A
4. D
5. D
6. B
7. C
8. B
9. A
10. D, but no cases of this being an issue.
11. C
12. B

2. CASES

3. THE ELECTRICIAN
• Found unconscious near a generator. Now awake but amnesic and confused
• Burns to chest and arms
• VWNL
• Ax?
• High voltage injury likely
• Transthoracic
• Mx?
• Resuscitate
• Survey injuries, esp burns and head
• Cx spine precautions and CT
• ECG
• UA
• CK/myoglobin
• IVH, targeting UO >1mL/kg/hr
• NVO – compromised RUL
• TF to FSH burns. Subsequent fasciotomy RUL

4. THE BLOW-DRYER BABE
• Using hairdryer whilst standing on a wet floor
• Felt “a shock”
• R palmar erythema only
• Mx?
• ECG normal
• Silver dressing, ADT, burns clinic FU

5. THE HAPPY CAMPERS
• 3 campers
• Tent struck by lightning
• Cardiac arrest w 10min CPR
• Bleeding ears and unable to hear
• Pale, mottled, numb LLs
• CPR continued and ROSC achieved despite fixed dilated pupils. In ICU, pupils returned to
normal – pt did not have severe hypoxic brain injury
• Ruptured TM
• Keraunoparalysis

6. HOUSE, MD
• Sticks knife into a power socket to see if there is an afterlife
• Suffers cardiac arrest, after which he is apparently fine
• Is this realistic?
• Consider the path of a current – where was the “grounding”?

7. TOUCHED BY GOD
• Professional storm chaser
• Pulseless blue legs amongst other injuries
• Started on heparin infusion on presumption of arterial thrombosis
• ICH results
• Keraunoparalysis
• Does not require treatment and spontaneously resolves

8. HUNGRY HILLARY
• Tried to get toast from toaster w knife 3mo ago. Seen in ED and
essentially unhurt apart from minor R hand burn.
• Now c/o entire R forearm diffuse pain, swelling, and coolness
• CRPS

9. TEETHING THOMAS
• Chewed electrical cord
• Minor oral burns
• Other considerations?
• Then develops airway oedema
• Eventually TF to burns unit
• Represents 2 weeks later with severe labial bleeding
• Eschar separation and labial artery bleeding
• Should have counselled parents on haemorrhage control

10. ELECTRICAL INJURY

11. EPIDEMIOLOGY
• ~25 deaths/year in Australia
• Majority young men in industrial setting

12. FACTORS INFLUENCING DEGREE OF INJURY
• Current, a flow of charge, measured in Amperes
• Voltage, the electrical potential difference driving the flow, the energy per unit of charge
• Resistance, the impedance to flow of charge
• Ohm’s law: I = V/R
• Current α voltage
• Voltage is used to classify injuries because it is the only variable that can be reliably measured.
• Current α 1/resistance
• Low resistance tissues: nerve, muscle, vessels, membranes.
• High resistance tissues: bone, fat, tendon
• Water on skin reduces resistance 40x!
• Power = VI = I2R = V2/R
• Heat = Pt = I2Rt = V2t/R
• Type of current
• DC causes muscle spasm and throwing
• AC can cause repeated spasm and grasping, depending on the frequency, leading to higher exposure time and possible dislocation
• Path of current through pt. Usually to the ground.
• Example: Household = 230V AC

14. MECHANISMS OF INJURY
• Current itself
• Thermal burns
• Mechanical trauma e.g. from throwing or convulsing

15. SOURCES
• >1000V
• Minimum of 24hr cardiac monitoring due to dysrhythmia risk
• BP monitoring due to autonomic dysfunction risk
• Serial neurovascular obs
• Admit cardiology or obs unless otherwise indicated by injuries
• <1000V
• And asymptomatic and examining normally – DC after ECG
• And mild Sx with normal ECG/UA – DC after few hours’ observation
• And ECG changes, LOC, injury – admit

16. LIGHTNING
• Likely admission, potentially ICU or burns unit
• Brief, ultra-high voltage, DC
• Tends to flash over the pt and into orifices e.g. mouth and ears, rather than go through the pt
• 32% mortality. Almost all from initial cardiac arrest or from resp arrest.
• In event of multiple casualty, triage priority altered. First treat those who appear dead. Often respond well to CPR/defibrillation.
• Morbidity is predominantly from neurologic issues.
• Immediate and transient: LOC, seizure, confusion, anterograde amnesia, weakness, paraesthesia, inattention, HA, irritability
• Lightning paralysis “keraunoparalysis”: LL vascular compromise and paralysis lasting a few hr only due to vasospasm and dysautonomia
• Immediate and persistent: hypoxaemic or haemorrhagic injuries
• Delayed: motorneurone disease-like effects
• Fewer burns. More CVS, resp, neuro complications including asystolic arrest. Shockwave effect like a blast.
• Otologic and ophthalmic injury common. TM rupture may be only sign of lightning in pt w collapse outdoors.
• Pt can be approached immediately.

17. TASER
• High voltage, low current electricity through the target
• <15sec and clinically well = NOT dangerous and pts do not
require observation
• All of the few deaths previously associated with taser have
involved dysrhythmia-inducing drugs also

18. CHEWED ELECTRICAL CORD
• Oral arc burns
• Plastics/max-facs for debridement/recon/oral splinting
• Risk of severe labial artery bleeding after delayed eschar separation – pts
need education pre-discharge
• Thinner skin in children = likely more severe injury
• Risk of airway obstruction

19. SYNDROMES

20. CARDIAC
• Dysrhythmia is the most common
• VF at low exposures, asystole at high exposures including lightning
• 4-17% of electrocutions
• Esp hand-to-hand electrocution
• Rarely delayed. Most cases of delayed dysrhythmia also had dysrhythmia initially. Get early ECG.
• Energy levels for cardioversion are unchanged
• Often respond well to defibrillation and resuscitation
• Myocardial injury uncommon
• Mx
• Prolonged resus as pts are young and outcomes are good even if in asystole and signs of brain death may be unreliable in this
group
• Cardiac monitor if dysrhythmia, LOC, or >1000V
• Troponin levels not well studied

21. RESPIRATORY
• Respiratory failure from respiratory muscle tetany or
respiratory centre injury or cardiac arrest
• Mx: secure the airway

22. BURNS
• Vary with voltage. Small, superficial, well demarcated for low voltage. Necrotic punctate ulceration for high voltage.
• Special lightning burns: linear along fluid lines, punctate, feathering (nonserious), thermal.
• Entry and exit. Often under-predict internal damage. Check head/hands/feet.
• Mouth in children.
• Skin flexture “kissing” burns often associated with underlying tissue damage.
• Consider airway burns from coexistent smoke inhalation
• Mx:
• May need more IVH than formulae suggest due to concomitant rhabdomyolysis
• Silver dressings
• ADT
• Elevate
• Burns specialist

23. NEUROLOGIC
• 50% incidence in high-voltage injury, likely because nerve tissue has lowest
resistance.
• Central: LOC, memory disturbance, weakness, spinal cord injury – ALS/TM-
like, seizure, confusion, coma, aphasia
• Autonomic dysfunction: dilated pupils, hypotension, hypertension, arrest,
syncope, vasoconstriction, thermodysregulation, tachycardia,
• Peripheral: motor and sensory, CRPS – may be delayed
• Need CT to differentiate between electric and traumatic effects
• Persistent: inattention, poor memory, impaired learning

24. MUSCULAR
• Commonly rhabdomyolysis, coagulation necrosis, compartment
syndrome from oedema
• Check for myalgia
• NV exam
• Mx: IVH aggressively, check electrolytes <4hourly esp watching
K+, UO >1mL/kg/hr, fasciotomy for compartment syndrome or
ongoing myonecrosis

25. VASCULAR
• Usually tunica media injury leading to aneurysm or rupture.
Intimal injury leads to thrombosis.
• Commonly in small arteries to muscle. Results in myonecrosis.

26. ORTHOPAEDIC
• Highest resistance. Generates high heat when current passes.
• Osteonecrosis, periosteal burns, matrix breakdown
• Trauma from throwing, convulsions, shockwaves. Posterior
shoulder dislocation common.
• Mx: as trauma patient

27. OCULAR AND OTOLOGIC
• Ophthalmologic
• Corneal commonest. Erosion, keratitis, scarring
• Cataract – may be delayed and pts w high voltage injury ought to be
warned, hyphaema, vitreous haemorrhage, optic neuropathy
• Hearing impairment
• Conductive from TM rupture, esp in lightning strike due to shockwave
• Sensorineural from cochlea electrocution

28. GASTROINTESTINAL
• Rare
• Curling’s ulcers in pt w >30% BSA burns. Mx: PPI.
• Ileus
• Vascular insufficiency

29. PREGNANCY
• Burns = uteroplacento blood flow changes and dysfunction can
occur, abruption, abortion, oligohydramnios, growth
retardation,
• CTG/FHR/USS
• Obstetric consultation
• Most have good outcome if low voltage and not transuterine
shock

30. CLINICAL APPROACH

31. HISTORY
• Source and voltage and type of current. Specificity is key as capacitors and
transformers in household appliances can alter the voltage substantially
compared to housing mains voltage.
• Other risk factors in pts w low-voltage exposure
• Duration of contact
• Water involvement
• Spasmic injury
• Transthoracic
• PMHx: cardiac
• Tetanus immunity

32. EXAMINATION
• Entry and exit burns
• High voltage pts
• Ophthalmic including fundoscopy for haemorrhage and optic neuropathy
• Otoscopy for TM rupture
• Neurovascular of extremities

33. INVESTIGATIONS
• Only ECG needed if asymptomatic and low voltage injury
• ECG
• FBC, UEC,
• Coag, G+H if trauma
• CK. Need serial if elevated as this predicts mortality, LOS, risk of amputation.
• Trop – unclear utility and should DW cardiology
• Imaging as for trauma pt
• UA for Hb/myoglobin. If positive, send urine for microscopy ?RBC vs myoglobin.

34. MANAGEMENT
• Resuscitation
• Triage arrested casualties first
• Prolonged CPR indicated – young pts w good outcomes
• Secure airway against burns and in event of resp arrest
• Neurologic death difficult to determine
• Treat as trauma
• Cx spine needs to be cleared
• Image if any neuro issue to distinguish electric and trauma effects
• Eyes and ears are particularly vulnerable
• Burns management including DTPa
• Cardiac monitor if LOC, ECG change, and transthoracic or >1000V exposure
• NV monitoring
• IVH for rhabomyolysis and burns
• Titrate to UO rather than using a formula

35. KEY POINTS
• Avoid being electrocuted on scene
• Do not withdraw resuscitation too early
• Signs of death are unreliable in this patient group
• Treat as trauma
• High voltage DC and lightning injury pts are often thrown violently
• High voltage AC pts may have violent muscle spasm
• Internal injury may be severe despite only minor burns in pts with high voltage exposure
• ECG for all patients
• Cardiac monitor pts w LOC, ECG change, and transthoracic or >1000V exposure
• Frequently need aggressive IVH due to burns and rhabdomyolysis
• UO target 1-1.5mL/kg/hr rather than burns formulae
• Monitor neurovascular status of involved extremities regularly due to high risk of compartment
syndrome, vasospasm, and neurologic effects.
• Counsel pts about delayed effects
• CRPS, inattention, STML, weakness, paraesthesia, depression, cataract

36. REFERENCES
• Environmental and weapon-related electrical injuries - UpToDate
• Electrical Injuries: A Review For The Emergency Clinician - Emergency
medicine practice 2009
• Lightning and Electrical Injuries . Christopher B. Colwell. Emergency
medicine. 2nd ed. 2013.
• Chapter 218: Electrical and Lightning Injuries. Caitlin Bailey.
Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e.
• https://lifeinthefastlane.com/ccc/electrical-injury/

37. MISCELLANY
• Man electrocuted arm to arm
• Intact NV obs initially. Later develops compartment syndrome.
• LITFL info
• Tintinalli info starting from prehosp care section