Electrical & Lightning Injury Richard Dionne MD Emergency Medicine –University of Ottawa March 2013.

Electrical & Lightning Injury

Richard Dionne MDEmergency Medicine –University of Ottawa March

2013

Electrical & Lightning Injury

• Goals & Objectives• Comprehensive understanding of Ohm’s law

• Discuss the differences of AC vs DC and it’s potential clinical impact

• Discuss the early and late systems complications seen in both and their management

• Comprehensive ER management of a victim of low vs High voltage electrical injuries

Case

Patient came into contact with electrical source, touching Left hand accidentally. Source Industrial motor?

What is your approach ?What do you need to know?

« Electrical Injury »

Damage proportionnal to current flow intensity

Ohm’s Law : Current : I = V/R

Intensity (amp) = Voltage / Resistance

Description

• Telephone lines: 65 V• Household circuits: 110 V• Range / Dryer : 220 V• Power lines: 220 V• Subway rails: 600 V• Residential Trunk lines: 7000 V

Current types• Alternating (AC)– Periodic cycles (reversal of flow)– Residential power– Produces muscle tetany & prolongs contact– Higher risk of Ventricular Fibrillation

• Direct (DC)– Continuous flow one direction– Defibrillators / industrial sources– Single forcefull contraction – throws patient– Higher risk of asystole

Resistance Mucous membranes 100 Ohm / cm2

Wet skin 1200 - 1500 “” Sweat 2500 - 3000 “” Skin 10 - 40 000 “” Plantar Skin 100 - 200 000 “” Callouses 1 - 2 000 000 “”

Bone > Tendon > Skin > Muscle > Vessels > Nerve

Intensity 1 - 5 mA … Tingling / paresthesia 4 mA … « Let-go » child 5 - 10 mA … « Let-go » adult 10 - 20 mA … Tetany 30 - 90 mA … Resp. arrest (medulla) 50 - 100 mA … Ventricular Fibrillation 2 - 5 A … Burns 5 - 10 A … Asystole

Case … What is the significance of this?

Video

Factors associated with Severity

Voltage … ( high > 1000 V… low < 1000 V ) Amperage … ( intensity of current ) Type of current … ( AC > DC ) Tissue resistance & Contact surface Contact duration … Current Trajectory …

hand-hand / hand-foot / head - foot / foot - foot

Environnemental … (water / metal / etc.)

Trimodal Distribution

• Toddlers• Household cords & outlets

• Teenagers• Risk-taking behavior

• Adults• Work related injuries

Types of Injury

• Primary Electrical Phenomena– Cardiac arrythmias / muscle tetany

• Tissue Destruction– Superfical & deep burns – Deep tissue injury / necrosis … misleading

• Secondary Injury from Trauma– Being thrown

Target Organ Injury• Neurology

• Respiratory arrest• Delayed neurologic injury ; RSD

• Vascular: • Thrombosis / Compartment syndromes

• Nephrology: • ARF & ATN / myoglobinuria

• Orthopedic• Posterior shoulder dislocation / trauma

• Ophtalmological• Corneal burns / delayed cataracts

Work-up• ECG• Urinalysis for myoglobin

• Cardiac monitoring• Prolonged monitoring not necessary in asymptomatic

patients with normal ECG, no dysrythmias & exposure < 240 V…

• Cardiac Markers• Abnormal ECG or dysrythmias• High-voltage exposure

Treatment

• A-B-C’s• Burns & Trauma• Fluid resuscitation as needed• Rhabdomyolysis– NaHCO3 / Lasix / Mannitol ?

• Pain control +++

Different Types

Flash Burns Arc Burns Contact Burns

Video

Case

25 yrs old was talking over an outdoor phone when lightning hit a metal post about 1 Km away. She felt a jolt on the phone and feels tinnitus, headache and tired ever since. No specific limb pain or burns felt.

Lightning Injury

• Lightning is a stream of negative current downward from cloud to ground

• Brief duration 1-100 msec

• Tends to pass over the skin rather than through (flashover)

« Lightning Injury » High energy level at a short duration …

Clinical : Asystole >>> V. Fibrillation

Cardiac automaticity restarts, but Respiratory arrest persists … « Medullary concussion »

Important : Rapid Ventilatory Support … Inverse Triage Notion if Disaster !!!

Lightning

• Mechanism of injury:– Direct strike– Side splash injury– Contact strike– Ground strike– Blunt injury / fall– Thermal burning– Usually outdoor activity / handling of electrical equipment

or telephones

Lightning• Cardio-Respiratory Arrest

• Medullary center “concussion” = triage reversed• Asystole (DC)

• Neurologic long term deficit • Paresthesias / Tinnitus / depression / etc.

• ENT• Ruptured tympanic membranes & ossicular disruption

• Ophtalmo• Cataract / retinal hemorrhages & detachment

• Dermatology• Ferning pattern that resolves

Ferning Flash Burn

Comparison Lightning vs High Voltage

Lightning High Voltage Duration instant prolonged

Energy Level- Voltage 3000 – 3 000 000 V > 1000 V

- Amperage 50 000 A 10 - 10 000 A

Character Direct (DC) Alternative (AC)

Pathway Flashover Horizon. / Vert. Burns Superficial Deep

Rythm Asystole V. Fibrillation

Myoglobinuria rare common

Fasciotomy rare common

Blunt injury explosive projection

Complications

1- Cardiovascular 2- Respiratory 3- Neurologic ( acute & long term ) 4- Renal 5- Musculoskeletal (Trauma & Burns) 6- Ophtalmology 7- ENT 8- GI

Complications : Neurologic

Short & Long term … Chronic pain syndrome Severe headache : post-concussive like syndrome Vertigo & Ataxia Seizures Neurocognitive :

short-term memory loss / personnality change / difficulty in multitasking or learning new abilities

Sleep distubances Peripherical nerves (médian & ulnar) Reflex Sympatic Dystrophy

When to discharge or admit?

Indication for Admission High tension « > 1000 Volts » …

or Low tension & associated :

Current via : thorax / head …Loss of consciousness …ECG anomalies or arythmia … Electrothermic (deep) burns …Neurovascular compromise of extremity …

Criteria for Discharge( Cunningham et al. )

1- Patient asymptomatic & low risk …

2- Tension < 220 Volts …

3- Exam & ECG initially normal

4- Observation 4 - 8h normal in ER ...

Case

A 14 month old bambino decides to snack with an electrical cord. It is an extension cord from an household appliance on 110V.

He presents to the ER with burns to the mouth, no active bleeding, no airway compromise.

Oral Burns

Contact Burn Mucosa & Eschar

Plastic Surgery Consultation … Need for splinting to prevent retraction scarring

Admission & Monitoring ? … eschar can fall & labial artery hemorrhage …

( up to 10 % in 3 - 5 days )

Case

A 22 yr old, 6 months pregnant, accidently felt a jolt when touching a lampshade. She felt the energy from her Right hand to her Right foot. It was regular household current of 110 V.

She is worried about her pregnancy...

Electrical Injury & Pregnancy

High risk for:MiscarriageFetal demiseStillbirthAbruptio placentae (trauma)

Risk of Stillbirth … Low voltage ... Fatovich et al. 73 % ( 15 pts ) ??? Einarson et al. 15 % ( 62 pts )

Electrical Injury & Pregnancy

High risk of fetal demise : current crosses uterus Fetus must less resistant to shock > 220 V First Trimester …

Observation of fetal movements …higher risk of fetal demise if dimished fetal movements

noted closely after incident...

Electrical & Lightning InjuryKey Concepts

• High-voltage injury can cause significant tissue & organ damage along the entry & exit pathway

• Patients with low voltage electrical injury who have only minor cutaneous burns may be discharged safely if ECG, urine & 4 hour monitoring is normal.

• Lightning injury may cause significant injury, mainstay is to observe these patients.

Video

TASER

Richard Dionne MDEmergency Medicine – University of Ottawa

March 2013

From

TASER

• Thomas A. Swift Electric Rifle (TASER)

• Mechanics:– Air rifle shot 10 meters away with 1200 V in 19 pulses per

sec. over 5 sec.– Short duration total charge of 50 000 V, but very low

amperage < 3 mA… (0.03 A)– Comparison…

• Wall outlet 110 V at 15 A• 60 W light bulb 0,5 A• Christmas Tree bulb 1 A

TASER

Conducted Energy Weapons

Traditional “Blunt” Pulse

High Energy, “Brute Force” Approach90% Energy Loss

Traditional “Blunt” PulseNew Shaped Pulse™

Arc Phase

Stim Phase

New Shaped Pulse™

Full Energy Penetration

TASER

• Between 2001 – 2008

• 334 Americans died after shock – (Amnesty International) … 50 directly related???

• June 2008, $5 million damages, death Robert Henson, 40, San Jose California

• 15% related to stun gun & 85 % related to amphetamines …

TASER

Canadian data

• Quebec Provincial Police 2006, used 51 times, no adverse outcomes

• RCMP in 2009, used 1106 times, no adverse outcome reported

TASER

• Oct 2007, Robert Dziekanski, 40, Vancouver Airport… Shocked 5 times

• Excited Delirium … vs … TASER ???

60% 60% SMALLERSMALLER

TASERConducted Energy Weapons

•Concerns have been raised about CEW role in deaths•5/18 patients in Stratton study tasered prior to death•Several studies have examined effect of taser on healthy volunteers

– 25 exercised to exhaustion then tasered for 15 seconds and EKG performed- no changes observed (Ho et al, JEM, 2011)

– 25 exercised to exhaustion then tasered for 5 seconds and performed EKG, vital signs, ABG, lactate- no difference between shocked and non-shocked (Vilke et al, Acad Emerg Med, 2009)

•But not acidotic, hyperthermic, hyperadrenergic people

TASERConducted Energy Weapons•Most common theory is that taser causes dysrhythmia

•Swerdlow et al, Acad Emerg Med, 2009

– 56 people died within 15 minutes of being tasered– 7% had shockable rhythm, 93% PEA or asystole– Time from collapse to first recorded rhythm less than 5 minutes

in 77% of patients– Only 2% collapsed immediately, 7% within one minute, and 91%

more than 1 minute later– “…electrically-induced VF is not a common mechanism of death

after tasering.”

Cause of Death in Exited Delirium

• Putting it all together– Hypertrophied, fibrotic heart– Hyperadrenergic state– Oxygen demand exceeds supply in setting of

tachycardia, hypertension, CAD, vasoconstriction, myocardial hypertrophy, and physical restraint of chest

– Severe acidosis requiring huge respiratory compensation, with physical restraint of the chest

– Cardiovascular collapse

Questions ?

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