Electrical Burns 6c67c

OKWEREKWU FRANCIS .C

 Introduction

 Epidemiology  Aetiology  Pathophysiology

 Clinical Features  Investigations  Treatment

 Prevention  Conclusion

Introduction  Burn injuries are a world wide problem.

They rank high among injuries suffered by man.  Since its inception in 1849, commercial use

of electricity has been one of the most potentially dangerous commodities in the world.

Introduction  Electrical injury includes electrocution,

electric shock, burns and secondary injuries.  The term electrical burn is used widely to

describe the variety of injuries created by supraphysiologic electrical energy interacting with living tissue.

Epidemiology  According to statistical data, 0.8-1% of

accidental deaths are caused by an electric injury.  Electric injury s for 1000 deaths each

year in the United States, with a mortality rate of 3-15%

Epidemiology  Approximately 20% of all electrical injuries occur in

children, with a bimodal peak incidence highest in toddlers and adolescents.  Most electrical injuries that occur in children are at home, with extension cords (60-70%) and wall outlets (10-15%) being by far the most common sources in this age group.  Electrical burns for 2-3% of all burns in children that require emergency room care.

Epidemiology  Electrical burns constituted 2.8% of total

burn issions.  Male: Female ratio was 1.8:1  44.9% of the patients were children with age range between 22 days – 14 years.  Department of Burns, Plastic & Reconstructive Surgery, National

Orthopaedic Hospital Enugu(Niger ian J Clin Pract. 2006 Dec;9(2):1247.)

Aetiology  Electrical burns are usually divided into low voltage

and high voltage injuries, the threshold being 1000volts.  a) Low voltage injuries: do not have enough energy to

cause destruction to significant amt of subcutaneous tissues. The entry and the exit points, normally in the fingers and toes suffer small deep burns.  b) High voltage injuries

Pathophysiology  Electrical energy causing direct tissue damage,

altering cell membrane resting potential, and eliciting muscle tetany.  Conversion of electrical energy to thermal energy, causing massive tissue destruction and coagulative necrosis.  Mechanical injury with direct trauma resulting from falls or violent muscle contraction.

Pathophysiology  Factors that determine the degree of injury include

Type of current  Resistance encountered  Current pathway  Magnitude of energy delivered  Duration of . 

Type of current  The repetitive nature of AC increases the

likelihood of current delivery to the myocardium, which can precipitate ventricular fibrillation.  In contrast, DC usually causes a single

violent muscle contraction, often thrusting the victim away from the source.

Resistance  In general, tissues with high fluid and

electrolyte content conduct electricity better.  Bone is the tissue most resistant to the flow of electricity.  Nerve tissue is the least resistant, and together with blood vessels, muscles, and mucous membranes offer a path of low resistance for electricity.

Resistance  Skin is the most important factor impeding

current flow. It is the primary resistor against electrical current, and its degree of resistance is determined by its thickness and moisture.  It varies from 1000 ohms for humid thin skin

to several thousand ohms for dry calloused skin.

Pathway  Transthoracic currents can cause fatal

arrhythmia, direct cardiac damage, or respiratory arrest.  Transcranial currents can cause direct brain injury, seizure, respiratory arrest, and paralysis.

Magnitude  The current intensity will also determine the

magnitude of injury. There may be individual variation on the energy dose for a specific effect.  Less energy is generally required in children, who have more water content and thin skin and, hence, better conductivity and less resistance.

Current intensity

Expected clinical manifestation

1 mA

Probable tingling sensation

3-5 mA

"Let go" current for an average child

7-9 mA

"Let go" current for an average man

16-20 mA

Tetany of skeletal muscles

20-50 mA

Paralysis of respiratory muscles (respiratory arrest)

50-100 mA

Threshold for ventricular fibrillation

Greater than 2 A

Threshold for ventricular fibrillation

15-30 A

Common household circuit breakers

240 A

Maximal intensity of US household current

Clinical Features          

Skin burns/Mouth burns Unconscious Bleeding Skeletal injuries Shock Dark coloured urine/ARF Respiratory arrest Tissue oedema/ Compartment syndrome Numbness/Paraesthesia Seizures

HAND TO HAND CURRENT FLOW

Management  Acute emergency, shout for help.  Secure yourself.  Separate the victim from the current's source. The

safest way to do so is to shut off the current e.g by throwing a circuit breaker or switch or by disconnecting the device from an electrical outlet.  Treat as multi-trauma patient with cervical immobilisation at least until the full extent of injuries has been quantified

Management  ABC’s  IV access  IV fluids-Ringer’s Lactate

 Monitor urine output -100ml/hr  ARF prevention(in case of myoglobinuria)  Tetanus prophylaxis  Analgesia, ulcer prophylaxis, antibiotics  Wound dressing

Management  Defribillation  Associated injuries-Splint limb, refer  Extremities – Fasciotomies for compartment syndrome  Debridement/amputation -non-viable tissue  Reconstructive surgery for mouth burns

Investigations  FBC  E,U,Cr  ECG x 24 hrs  CXR  ABG  X-ray, CT  Wound swab- MCS

Complications  Seizures  Peripheral nerve damage  Psychiatric problems from depression to aggressive

behaviour  Cataracts  Paraplegia/Quadriplegia  Deformities

Prevention  Education about and respect for electricity are

essential.  Ensure electrical devices are properly designed, installed, and maintained.  Electrical wiring should be installed and serviced by properly trained personnel.  Outlet guards reduce risk in homes with infants or young children.

PREVENTION CONTD.  Any electrical device that touches or may be touched

by the body should be properly grounded.  Three-pronged outlets are safest.  Circuit breakers that interrupt (trip) circuits when current as low as 5 milliamperes leaks are advisable in areas that get wet, such as kitchens and bathrooms and outdoors.

CONCLUSION  Although electrical burns represent only a small

proportion of burn injuries, the incidence of complications, mortality and morbidity, and disability is high. Such injuries can be prevented with proper educational programmes designed to suit the community.

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