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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


  • 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


    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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