Electrical injuries
Download
1 / 33

Electrical Injuries - PowerPoint PPT Presentation


  • 138 Views
  • Uploaded on

Electrical Injuries. Robert Primavesi, MDCM, CCFP(EM) Montreal General Hospital McGill University Health Centre. Electrical Injuries Goals. To identify the important complications of electrical injuries. To expose the pitfalls in diagnosis. To explore the controversies in management.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Electrical Injuries' - aziza


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Electrical injuries

Electrical Injuries

Robert Primavesi, MDCM, CCFP(EM)

Montreal General Hospital

McGill University Health Centre


Electrical injuries goals
Electrical Injuries Goals

  • To identify the important complications of electrical injuries.

  • To expose the pitfalls in diagnosis.

  • To explore the controversies in management.


Electrical injuries objectives
Electrical InjuriesObjectives

  • Define the population at risk.

  • Determine the factors predicting the severity of injury.

  • Differentiate between high-voltage and low-voltage injuries.

  • Recognize which patients require admission or referral.

  • Decide which patients need cardiac monitoring.



Top 10 myths of electrical injury myth 1

Top 10 Myths of Electrical InjuryMyth #1

Electrical Injuries Are Uncommon


Electrical injuries epidemiology
Electrical InjuriesEpidemiology

  • 124 deaths in Quebec 1987-1992

  • 5X additional patients requiring emergency treatment

  • 3-5% of all burn centre admissions

  • Bimodal distribution

    • Toddlers

    • Workforce


Top 10 myths of electrical injury myth 2

Top 10 Myths of Electrical InjuryMyth #2

Voltage Is the Most Important Determinant of Injury


Electrical injuries factors determining severity
Electrical InjuriesFactors Determining Severity

1. V = voltage

2. i = current

3. R = resistance

OHM’S LAW: i = V / R


Electrical injuries factors determining severity1
Electrical InjuriesFactors Determining Severity

JOULE’S LAW:

Power (watts) = Energy (Joules)

time

= V x i

= i2 x R


Electrical injuries factors determining severity2

Mucous membranes

Vascular areas

volar arm, inner thigh

Wet skin

Sweat

Bathtub

Other skin

Sole of foot

Heavily calloused palm

Skin Resistivity - Ohms/cm2

100

300 - 10 000

1 200 - 1 500

2 500

10 000 - 40 000

100 000 - 200 000

1 000 000 - 2 000 000

Electrical Injuries Factors Determining Severity


Top 10 myths of electrical injury myth 3

Top 10 Myths of Electrical InjuryMyth #3

High Voltage Is More Likely to Kill Than Low Voltage


Electrical injury factors determining severity
Electrical InjuryFactors Determining Severity

  • A momentary dose of high voltage electricity is not necessarily fatal.

  • Low voltage is just as likely to kill as high voltage.

RK Wright, JH Davis. The investigation of electrical deaths: a report of 220 fatalities.

J. Forensic Sci. 1980; 25:514-521.

Cunningham PA. The need for cardiac monitoring after electrical injury. Medical Journal

of Australia. 154(11): 765-6, June 1991.


Top 10 myths of electrical injury myth 4

Top 10 Myths of Electrical InjuryMyth #4

The Extent of the Surface Burn Determines the Severity of Injury


Electrical injuries patterns of injury
Electrical InjuriesPatterns of Injury

  • Direct contact

    • Direct tissue heating

    • Contact burns (entry and exit)

    • Thermal burns


Top 10 myths of electrical injury myth 5

Top 10 Myths of Electrical InjuryMyth #5

The Pathway the Electrical Current Takes Through the Victim Predicts the Pattern of Injuries


Electrical injuries patterns of injury1
Electrical InjuriesPatterns of Injury

Skin Resistivity

Least Nerves

Blood

Mucous membranes

Muscle

Intermediate Dry skin

Tendon

Fat

Most Bone


Electrical injuries effects of 60 hz current
Electrical InjuriesEffects of 60 Hz Current

1 mAmp Threshold of perception

5 mA Maximum harmless current

6 mA Ground fault interrupter opens

10 mA “Let-go” current

20 mA Possible tetany of resp muscles

100 mA VF threshold

6 A Defibrillation

20 A Household circuit breaker opens


Top 10 myths of electrical injury myth 6

Top 10 Myths of Electrical InjuryMyth #6

Electricity Kills by Causing Myocardial Damage

CK and/or Troponin Are Good Markers for Myocardial Damage in Electrical Injury


Electrical injuries patterns of injury2
Electrical InjuriesPatterns of Injury

  • James T., Riddick L., Embry J. Cardiac abnormalities demonstrated post-mortem in four cases of accidental electrocution and their potential significance relative to non-fatal electrical injuries of the heart. American Heart Journal. 120: 143-57, 1990

  • Robinson N., Chamberlain D. Electrical injury to the heart may cause long-term damage to conducting tissue: a hypothesis and review of the literature. Int J Cardiol. 53: 273-7, 1996


Top 10 myths of electrical injury myth 7

Top 10 Myths of Electrical InjuryMyth #7

All Patients With Electrical Injury Require 24 Hours of Cardiac Monitoring


Electrical injuries cardiac monitoring
Electrical InjuriesCardiac Monitoring

  • Alexander L. Electrical injuries of the nervous system. J Nerv Ment Dis 1941; 94: 622-632

  • Jensen PJ, et. al. Electrical injury causing ventricular arrhythmias. Br heart J 1987; 57: 279-283

  • Norquist C., Rosen CL., Adler JN., Rabban JT., Sheridan R. The risk of delayed dysrhythmias after electrical injuries. Acad Emerg Med. 6: 393, 1999


Electrical injuries cardiac monitoring1
Electrical InjuriesCardiac Monitoring


Electrical injuries cardiac monitoring2
Electrical InjuriesCardiac Monitoring

  • Cardiac monitoring is not justified in ASYMPTOMATIC patients,

  • Or, in patients with only CUTANEOUS burns,

  • Who had a normal ECG after a 120 v or 240 v injury.


Top 10 myths of electrical injury myth 8

Top 10 Myths of Electrical InjuryMyth #8

ALL Patients Who Are Asymptomatic and Who Have a Normal ECG After a 120V or 240V Injury Can Be Safely Discharged From the ED


Electrical injuries patterns of injury3
Electrical InjuriesPatterns of Injury

  • Pregnancy

    • Fetal monitoring is mandatory for pregnant patients

  • Oral commisure burns

  • Cataracts

  • Delayed neuro-psychological sequelae


Top 10 myths of electrical injury myth 9

Top 10 Myths of Electrical InjuryMyth #9

The HYDRO QUEBEC GUIDELINES Provide the Standard of Care for Electrical Injuries


Electrical injuries summary the challenges
Electrical InjuriesSummary - The Challenges

  • Electrical injuries involve multiple body systems.

  • Entry and exit wounds fail to reflect the true extent of underlying tissue damage.

  • Electrical current may cause injuries distant from its apparent pathway through the victim.

  • Controversies exist regarding indications for admission and cardiac monitoring following low voltage injuries.


Electrical injuries the future
Electrical InjuriesThe Future

  • Surveillance electrographique des patients ayant subi une électrisation: Étude prospective multicentrique. Investigateur principal: Benoit Bailey, MD MSc FRCPC

  • 21 sites across Quebec – including RVH, MGH, MCH

  • Primary objectives:

    • determine the prevalence of cardiac arrhythmias in patients on initial ECG

    • determine the prevalence of late arrhythmias in patients who undergo cardiac monitoring


  • Secondary objectives:

    • evaluate the importance of electrical injury in Quebec’s EDs

    • given a normal initial ECG, evaluate if late arrhythmias develop in patients with tetany, current across the heart, or with >1000V

    • given a normal initial ECG, evaluate if late arrhythmias develop in patients with PMHx of cardiac disease, or decreased skin resistance

    • evaluate the incidence of cardiac problems in the year following electrical injury


  • Secondary objectives, cont’d:

    • accumulate prospectively an experience with applying the Hydro Quebec protocol

    • determine the utility of measuring CK, CK-MB in predicting ECG abnormalities and the development of late arrhythmias

    • determine the utility of measuring Troponin in predicting ECG abnormalities and the development of late arrhythmias


Top 10 myths of electrical injury myth 10

Top 10 Myths of Electrical InjuryMyth #10

“er” is an Accurate Reflection of Life in the ER


Electric shock what should you do

Electric Shock:What Should You Do?

The victim:

Felt the current

pass through

his/her body

The current

passed through

the heart

Yes

Yes

No

No

Was held by the

source of the

electric current

Yes

1 second

or more

Yes

No

No

Lost

consciousness

Cardiac Monitoring

24 hours

Yes

No

Touched a voltage

source of more

than 1 000 volts


Electric Shock:What Should You Do?

Page 2.

Touched a voltage

source of more

than 1 000 volts

Cardiac Monitoring

24 hours

Yes

No

Yes

Has burn marks

on his/her

skin

The current

passed through

the heart

Evaluate and treat burns

(surgical evaluation,

look for myogolbinuria, etc.)

Yes

No

No

Was thrown from

the source

Evaluate trauma

Yes

No

Is pregnant

Evaluate fetal

activity

Yes

No

Direction Services de Sante

Hydro Quebec, 1995

BENIGN SHOCK

Reassure and discharge


ad