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Electrical & Lightning Injuries. Carly Thompson EM-Resident April 9, 2009. Electrical Injuries Definitions Epidemiology and Physics Physiologic Effects of Electricity Specific Injuries ED Management of Electrical Injuries Cases. Lightning Pathophysiology of Lightning

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electrical lightning injuries

Electrical & Lightning Injuries

Carly Thompson

EM-Resident

April 9, 2009

outline
Electrical Injuries

Definitions

Epidemiology and Physics

Physiologic Effects of Electricity

Specific Injuries

ED Management of Electrical Injuries

Cases

Lightning

Pathophysiology of Lightning

Specific Injuries: Lightning

ED Management

Cases

Outline
electric injuries
Electric Injuries

Definitions

  • Electric shock – response
  • Electrocution – death
  • Electrical injury

– tissue damage

  • Electrical burn

– cutaneous injury

slide4
550 Electrocutions / Year in USA (1998)
    • 50% of low-voltage <1000 V AC no visible burns or marks
  • 100 Lightning Deaths / Year USA
    • Underestimate?
  • 17 000 Electric Injuries / Year USA
  • 300 Lightning Injuries / Year USA
epidemiology
Epidemiology

3 Groups at Risk for Electrical Injuries:

    • Toddlers
    • Adolescents
    • Electrical Workers (1/10 000 deaths/year)

Lightning Injuries

Risks:

  • Transportation: Car, plane, water
  • Storms or blue sky!

Mortality:

  • 0.5 / million in US – 8.8 / million rural SA
  • 70-90% survival rate
  • 75% of survivors will have sequelae
physics 101
Physics 101
  • Electric flow / current = Amp
  • Electric potential difference = Volts
  • Resistance = Ohms
    • Conductors: high fluid, electrolyte content – nerves and blood vessels, sweaty skin, saliva, muscle
    • Insulators: high resistance – bone, dry skin

Ohm’s Law

I (Current) = V (Voltage) / R (Resistance)

Current is directly proportional to potential difference, and inversely proportional to resistance.

Example = Grasp 120V source, with 1000Ohms resistance = 120mAmps

types of current
Types of Current
  • What are the two types of current?
ac dc
AC/DC

How did the band AC/DC gain their name?

They saw it on the back of their older sister’s sewing machine.

  • AC – alternating current

Homes, usually 60Hz

  • DC – direct current

Batteries, lightning

physiologic effects
Physiologic Effects
  • Related to amount duration, type, path
  • Current travels along multiple paths, not only path of least resistance
  • Nerves and blood vessels – least resistance
  • Muscles have most flow due to greatest area
  • Nerves have higher current density -> significant injury
physics 102
Physics 102
  • Electrical energy -> deposited as heat
  • Heat causes the most tissue damage

Joule’s Law

Energy = I2 x R x time

Energy = (V2 x time) / R

Therefore the heating of tissues increases according to the square of the applied voltage, and is directly proportional to the time the voltage is applied.

electricity
Electricity

Power Line: 7620V

Lines outside house: 220 / 240V

Subway: 660V

High Voltage Injury

  • >1000 V
  • Severe skin burns

Low Voltage Injury

  • Cutaneous burns often minimal with household voltage, unless several secs contact
  • Electrical burns absent in 40% of low voltage deaths
  • 110V can cause V fib
trivia
Trivia

What was AC/DC’s first album?

What is considered high voltage?

>1000 V

cardiovascular injuries
Cardiovascular Injuries
  • 1° cause of death from electrocution
  • Low-voltage -> v fib
  • High-voltage AC and DC -> transient asystole
  • Also: ST, PACs, PVCs, a fib, 1st / 2nd AV block
  • Vigorous resuscitation!!!
    • Victims are often young without CVD
    • Not possible to predict outcome based on rhythm
  • Vascular injury -> spasm -> delayed thrombosis or aneurysm formation, compartment syndrome
cns and peripheral nerve injuries
CNS and Peripheral Nerve Injuries
  • 50% have impairment (high-voltage)
    • Transient LOC
    • Agitation, confusion,
    • Coma
    • Seizures
    • Quadriplegia, hemiplegia, paresthesias
    • Aphasia, visual disturbances
spinal cord injuries
Spinal Cord Injuries
  • Vertebral fractures – multilevel!
  • Delayed injury
    • ascending paralysis
    • complete or incomplete cord
    • transverse myelitis
  • MRI results not closely correlated to outcome
eye and ear
Eye and Ear

Eye Injuries

  • Cataract formation weeks to years later
  • Retinal detachment, corneal burns, intraocular hemorrhage, intraocular thrombosis

Ear Injuries

  • Late complications of hemorrhage into TM, middle ear, etc. -> mastoiditis, sinus thrombosis, meningitis, brain abscess
  • Hearing loss immediate or late
cutaneous wounds
Cutaneous Wounds
  • Entry / exit wounds – painless, gray

Treatment

  • Cleansing, Td
  • Silver sulfadiazine
  • Mafenide
    • Full-thickness burns – penetrates eschar
    • <25% BSA only – inhibits carbonic anhydrase, painful
  • Observe for neurovascular compromise, compartment syndrome
  • Splint extremities, early surgical debridement, vascular reconstruction and skin graft
orthopedic injuries msk
Orthopedic Injuries / MSK
  • Fractures 2° to tetany, falls
  • Shoulder dislocation (voltages >110V)
  • Muscle +++heat -> periosteal burns, osteonecrosis
  • Severe arterial spasm -> compartment syndrome
  • Muscle breakdown -> rhabdomyolysis -> myoglobinuria and renal failure
blast and inhalational injuries
Blast and Inhalational Injuries

Blast Injuries

  • Strong blast pressure -> head injury, mechanical trauma, arterial air emboli

Inhalational Injuries

  • Ozone -> mucous membrane irritation, decreased pulmonary function, pulmonary hemorrhage, edema
  • Carbon monoxide, etc. assoc. with fires
gi injuries
GI Injuries
  • Suspect in patients with burns of abdo wall, or trauma
  • Lethal injuries – reported only at autopsy
  • Gastric ulcers – Curling’s ulcers
  • Fluid resuscitation -> abdominal compartment syndrome with restrictive surface burns
slide23
DIC
  • May be due to thermal injury or tissue necrosis
  • Low-grade DIC from hypoxia, vascular stasis, rhabdomyolysis, release of procoagulants
  • Tx: eliminate precipitating factor by early surgical debridement
  • FFP or cryo as needed
oral burns
Oral Burns
  • Children
  • Unilateral
    • Lateral commissure, tongue, alveolar ridge
  • Systemic complications rare
  • Vascular injury to labial artery
    • Severe bleeding 10% cases
    • Occurs 5 days – 2 weeks when eschar separates
oral burns1
Oral Burns

Treatment

  • Admission – monitoring
  • Outpatient – reliable parents, who can be shown how to control bleeding, consideration?
  • Saline rinses, swabs to debride necrotic tissue
  • Petrolatum-based Abx for soothing effect
  • Specialty consultation – splinting / surgical procedures to prevent deformity and dysfunction
tasers
Tasers
  • Sinusoidal electrical impulses 10-15Hz
  • High voltage 50 000V for Taser
  • Low Amps and low average energy
  • 2001-2007 245 deaths after Taser

Injuries

  • R on T phenomenon -> v fib
  • Pacemaker or ICD malfunction
  • Death more likely with concomitant drug use (PCP, cocaine), trauma from struggle, preexisting CAD
  • Ocular injuries
  • Other: burns, lacs, rhabdo, testicular torsion, miscarriage
accident scene rescuer safety
Accident Scene: Rescuer Safety

Downed Power Lines

  • Electrocution possible, recommend 9m away (3m may be enough)
  • Reapplication of voltage may occur -> jumping power lines

Victims

  • Victims in contact with source may be “active”
  • Voltage >600V -> dry wood, rubber boots may conduct electricity
  • Persons inside vehicle in contact with power line, likely to be killed if they step out
ed treatment
ED Treatment

Resuscitation

  • ABCs as per trauma
  • ACLS
  • Spinal immobilization
  • Careful physical exam!

Investigations

  • Labs: High-voltage, extensive burns, evidence of systemic injury
  • CBC, lytes, Cr, BUN, CK, serum / urine myoglobin
  • Imaging as indicated, clear spines
ed treatment1
ED Treatment

Fluid Resuscitation

  • Fluid requirements > Parkland’s formula
  • Visible damage < internal damage!
  • Initial fluid bolus: 20-40mL/kg/ 1st hr
  • Considerations:
    • Fluid load to prevent rhabdomyolysis
    • Avoiding over-resuscitation in patients with restrictive burns on abdomen -> prevent compartment syndrome
disposition
Disposition

Admission:

  • In contact >600V
  • Symptoms (CP, palp, LOC, confusion, weakness, dyspnea, abdo pain)
  • Signs (weakness, burns with subcut damage, vascular compromise)
  • Ancillary changes (ECG, CK, myoglobinuria)
  • Cardiac monitoring: If ECG abnormal

No Admission:

  • Household voltage injury 100-220V in adult +
  • Neglibible risk for delayed arrhythmias +
  • Asymptomatic, normal ECG and normal exam -> d/c
electric injury in pregnancy
Electric Injury in Pregnancy
  • Increased rate of fetal damage or loss after apparent harmless contact
    • Monitor x 4 hours in women >20-24 weeks GA
    • Monitor >24 hours if LOC, ECG abN, hx of CVD
    • Fetal ultrasonography at presentation, then at 2 weeks
  • No proof that monitoring or tx can influence outcome
electric injury in children
Electric Injury in Children
  • Children with only hand wounds from outlet, but no cardiac or neurologic involvement can be d/c home with wound care
  • Consider admission if equivocal home safety or reliability
  • Guidelines for ECG in children:
    • Tetany
    • Decreased skin resistance by water or burns
    • Unwitnessed event
  • Guidelines for cardiac monitoring x 24 hours:
    • Past cardiac hx
    • LOC
    • Voltage >240V
    • Abnormal ECG
cardiac monitoring in children
Cardiac Monitoring in Children

Bailey et al. (2000). Experience with guidelines for cardiac monitoring after electrical injury in children. Am J Emerg Med; 18(6):671-5.

  • July 1994 – June 1998
  • Tertiary pediatric teaching hospital
  • 224 cases
    • Cardiac monitoring on 13% (all normal)
    • No morbidity 0/172 patients
    • No mortality 0/224
case 1
Case 1
  • 30 yo M electric worker
  • Found down at steel plant
  • Thermal burn – lateral head
  • Presenting in asystolic arrest

What do you do?

How long do you continue treatment?

case 1 cont d
Case 1 Cont’d

Thoughts . . .

  • Resuscitation as per ACLS
  • Spinal precautions
  • Vigorous resuscitation as patient is young and otherwise healthy, heart may spontaneously regain automaticity

Conclusion . . .

  • 45 minutes in ED resuscitation – no cardiac activity
  • Code called
summary electrical injuries
Summary: Electrical Injuries
  • Low-voltage <600V -> may be D/C if asymptomatic
    • Immediate cause of death: V Fib
    • Children: oral burns – consider labial artery bleed

? admission

  • High-voltage >1000V -> admit for observation and cardiac monitoring
    • Asystole, treat cardiac arrest vigorously
    • Deep tissue destruction with high fluid needs
    • Myoglobinuria and renal failureis common
    • Trauma: thrown
    • Immediate cause of death: Apnea
trivia1
Trivia
  • Name a team, a song and a runner who all have something in common with lightning.

Tampa Bay Lightning

Lightning Crashes – Live

Usain “Lightning” Bolt

http://www.youtube.com/watch?v=GIKYWlAPHVQ

pathophysiology
Pathophysiology
  • Different injury pattern, severity, tx
  • Lightning = extremely high-voltage DC
  • Brief, intense, thermal radiation producing rapid heating and expansion of surrounding air
  • Flashover = less likely to cause internal cardiac injury or muscle necrosis
  • TM perforation, internal contusion, tear clothing, melt metal, intense photic injury
mechanism of injury
Mechanism of Injury
  • Direct strike – direct contact
  • Side flash – hits nearby object
  • Contact strike – hits object being held
  • Ground current – through ground
  • Upward streamer – weak streamer
cardiac injury
Cardiac Injury
  • Htn, tachycardia – sympathetic activation
  • Depolarization -> sustained asystole
  • Other:
    • global myocardial contractility depression
    • coronary artery spasm
    • pericardial effusion
    • atrial and ventricular arrhythmias
  • ECG: acute injury – ST elevation, long QT, T wave inversion (neurologic injury)
  • MI is unusual
  • Cardiac automaticity may return spontaneously
respiratory issues
Respiratory Issues

Respiratory arrest

  • Due to paralysis of medullary resp centre
  • Critical prognostic factor
neurologic injury
Neurologic Injury
  • Common Injuries:
    • ALOC
    • Temporary lower extremity paralysis
    • Seizures
  • Lethal injuries: heat-induced coagulation of cortex, epidural / subdural, ICH
  • Autonomic dysfunction: mydriasis, anisicoria
  • Immediate and transient effects:
    • LOC, confusion, amnesia, paralysis - keraunoparalysis
  • Delayed and progressive effects:
    • Seizures, spinal muscular atrophy, ALS, parkinsonian syndromes, progressive cerebellar ataxia, myelopathy with paraplegia or quadriplegia, chronic pain
neurologic injury1
Neurologic Injury

Indications for CT:

  • Coma
  • ALOC
  • Persistent headache
  • Confusion
neurologic injuries
Neurologic Injuries

Spinal Cord Injuries

  • Fractures may be caused by tetany, falls, secondary trauma
  • Maintain spinal precautions
  • Image entire column due to multilevel fractures
neurologic injuries1
Neurologic Injuries

Ocular

  • Lightning-induced cataracts
  • Also: hyphema, vitreous hemorrhage, abrasions, uveitis, retinal detachment or hemorrhage, optic nerve damage

Auditory

  • TM rupture
  • Strike along phone: persistent tinnitus, sensorineural deafness, ataxia, vertigo, nystagmus
cutaneous injuries
Cutaneous Injuries
  • Lictenberg Figures
    • Superficial ferning
    • Disappear in 24 hours
    • Pathognomonic for

lightning strike

cutaneous injuries1
Cutaneous Injuries
  • Flash burns: erythema
  • Punctate burns: cigarette burns <1cm full- thickness
  • Contact burns: metal close to skin
  • Superficial erythema and blistering burns
  • Linear burns: <5cm wide in skin fold
  • Entrance and exit wounds - rare
rescuer safety
Rescuer Safety
  • Beware of the “lightning strike” victim that may truly be the victim of knocked down power lines
  • Look for evidence of lightning: hx of electric storm, blast effect, torn clothing, melted objects, melted nylon cloths, burned vegetation
  • Triage: Those who are sickest – treat first!
ed management
ED Management
  • ABCs, IV, O2, monitor
  • Hypotension is an unexpected finding – warrants investigation
  • Careful exam for secondary injuries, burns, current path
  • Labs: CBC, lytes, BUN, Cr, glucose, CK, urine for myoglocin
  • ECG
  • Imaging as indicated
disposition1
Disposition
  • Admission for observation recommended
  • No neuro injuries, normal ECG, monitoring -> may consider d/c home
  • Neurologic and ophthalmic referral recommended
pregnancy considerations
Pregnancy Considerations
  • Fetal injury and death more common even after little or no maternal injury (amniotic fluid)
    • Review: 11 women who survived lightning
    • 5 cases of fetal or neonatal death
    • Abruption can occur
  • Ultrasonography recommended
  • Maternal uterine activity and fetal HR monitor x 4 hours
case 3
Case 3

You are working at Foothills one stormy afternoon, and there is a soccer game going on at McMahon Stadium . . .

You get a patch . . .

3 patients
3 Patients
  • Patient 1: Full cardiac and respiratory arrest. Apparently a direct strike. Has Lichtenburg figures.
  • Patient 2: Altered, shallow breathing, mottled, deformity to R femur.
  • Patient 3: Complaining of paralysis to legs, flash burns to torso.
case 3 cont d
Case 3 Cont’d
  • How do you triage these patients?
  • In contrast to multiple victim events caused by mechanical trauma . . .
  • Persons with lightning injury who appear dead (resp +/- cardiac arrest) should be treated first!!!
summary lightning injuries
Summary: Lightning Injuries
  • Lightning is extremely high-voltage DC
  • CV: Causes asystole in arrest
  • Neuro: Apnea from medulla injury,
  • MSK: Explosive effect of shock wave
  • Cutaneous: Lichtenberg figures
  • Tx: ABCs, treat sickest first (even ?dead!)
  • Get ocular and neuro assessment
  • Admission for observation
thanks

Thanks!

Thanks also to Marc Francis and James Huffman for pictures and cases!

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