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Electrocution: Prehospital Care of Electrical Burns


Cable Exposed Electrocution

 

Electrical Burn Categories

Low Voltage – A low voltage burn is caused by contact with an electrical source that’s 1000 volts (some classify as 500 volts) or less.

 

Why does this matter to an EMT?

 

Because households commonly use around 120/240 volts, with large appliances using 240 volts. This means patients electrocuted by outlet will have a low voltage burn, which has different considerations for the EMT than a high voltage electrical injury.

 

People often assume low voltage electric burns are always minor injuries. However, they can induce ventricular fibrillation or another arrhythmia. A low voltage electrical injury often causes only superficial skin injury, which is why they are thought of as minor electrical burns. They can occasionally cause the patient to clamp on to the source of electricity which may increase the burn injuries.   

 

In fact, the two most common results of low voltage electric burns are either no injury at all or death caused by ventricular fibrillation. The basic EMT will need to do CPR on these patients until an ALS unit arrives that can defibrillate. Patients who experience electrocution for longer and can’t let go are more at risk for cardiac complications.

 

Patients at risk for low voltage electrical injury

 

• Patients electrocuted in water or with wet skin.

• Patients who can’t let go during the electrocution.

• The electric current travels across the patient’s chest.

• Patient with electrical burn entry and exit wounds visible.

• Any patient who falls a great distance as a result of electrocution.

 

 

High voltage – High voltage electrical burns are electrocution from a source that’s over 1000 volts. When a patient experiences electrocution from a high voltage source, the current travels through the body causing severe electrical burns.

 

Usually, an EMT treating a patient with a high voltage electrical injury will need to provide more interventions than for a low voltage patient. Even if the patient appears to have the same injuries.

 

However, both a high voltage injury and low voltage injury can cause significant damage to skin and tissue at the electrical burn entry and exit wounds. These electrical burns typically occur on the hands, wrist, feet, and fingers.

 

Details about the damage caused by a high voltage electrical injury is discussed below in the pathophysiology section. Another difference between a low voltage and high voltage injury is that the latter tends to lead to asystole, while the former tends to cause ventricular fibrillation.

 

Causes of Electrical Injury

Electric burns will occur when the body comes in contact with an electric current or source of electricity. Some causes of an electrical burn injury are:

 

→ Grabbing a live wire or power cord.

→ Not turning off the power supply prior to repairs and appliance installation.

→ Electrocution by lightning.

→ Children (and pets) biting on power cords.

→ An electric device falling into water.

→ Electrocuted by outlet – person pushes metal objects into an electrical outlet.

→ Conductive objects, like a ladder or shovel, coming in contact with a live source of electricity.

 

A common cause of electric burns is coming in direct or indirect contact with live wiring or electrical equipment while on the job. These can include circuit breakers, lighting fixtures, control panels, transformers, power lines and junction boxes.

Electrician on Powerline at risk for electrocution

 

Risk Factors For Electric Burns

Adults and children are both at risk for electric burns, but for different reasons. Children and infants are more likely to sustain an electrical injury in a home; from outlets, appliances, etc. while adults are more likely to experience electrocution in an occupational setting. Men are at higher risk for electric burns because there are more male employees in the high risk jobs.

 

High risk jobs for electrocution are construction worker, roofer, agricultural worker, carpenter, lineman or electrician.

 

There are also situations that can lead to a higher risk of electrical injury. These include:

• New construction.
• Digging around the home: power lines are in the air & in the ground.
• Working outside with a ladder.
• Outdoor sports and recreation activities outside.
• Backyard tree trimming: both by a professional & homeowner.

 

Scene Safety

Scene safety is an important aspect of electric burn management. While going through EMT or Paramedic training we are taught to verbalize scene safety over and over again.

 

Scenes with live wires or electrocuted patients who have high voltage electrical burns are exceptionally dangerous to EMS personnel. If you are called out to a patient suspected of an electric burn, be ready to survey the scene before exiting the ambulance. Don’t pull up next to the patient because they may still be in contact with the electricity source.

 

Park a safe distance away and call for additional personnel if the power needs to be turned off. In the case of a high voltage electrical injury, like downed electric lines outside, wait until someone appropriately trained to work with them gets on-scene.

 

Power lines can be connected to a backup generator, which means the main power source could be turned off but the lines could still be live. This is why it’s so important to have a trained professional handle turning them off and removing them from the path of first responders.

 

Don’t touch the patient until it is safe to do so. You may have to wait until the patient is removed from the source of the electricity before you can provide care to your patient. This is a difficult thing to do while on scene, but your safety and the safety of your partner is a priority in electrocution situations.

 

It’s not recommended to grab a wooden board or other nonconductive object and move the electric wires away from the patient. This is too risky for first responders because objects around the patient can contain an electric current. Electric burns can occur to the first responder from touching a vehicle or even the ground while trying to rescue the patient.

 

Emergency Medical Technicians (EMT) and other EMS should stay a safe distance away until there is no chance of receiving an electrical burn injury. Afterall, if you become injured on scene you won’t be able to help the patient.

 

Lightning Strike Scene Safety

For EMTs lightning strike patients provide a much safer scene than other electrical burn injury patients. By the time you arrive on scene the source of electricity should be gone, removing the danger of electrocution to EMS personnel. For these patients, EMTs can determine scene safety and approach the patient to provide treatment for any electrical injury. 

High Voltage Lightning

 

Pathophysiology of Electrocution

There are many factors that affect how severe electrical burns will be. Voltage, resistance, type of current, strength of current, pathway through the body and time spent in contact with electrocution source all effect electrical injury symptoms.

 

This article won’t go into the details of Ohm’s Law and Joule’s Law, but it will mention a couple important notes about electric burns in the human body.

  1. During electrocution, the current will often take the path of least resistance out of the body, to the ground.
  2. As the electric current meets more resistance in the body, heat energy is created and causes electrical burns.

 

What Happens During Electrocution?

A high voltage electrical injury is a good example for explaining what happens during electrocution. When the human body comes in contact with a source of electricity it can conduct electricity.

 

Electricity will attempt to ground itself using the human body and it will usually take the path of least resistance. Blood vessels, nerves and muscles have a higher water and electrolyte content which makes them less resistant than bone, tendons, fat and dry skin.

 

Patient Resistance to Electricity:

Electricity will attempt to take the path of least resistance out of the patient
More ResistantLess Resistant
Dry SkinWet Skin
BoneNerve
FatBlood Vessel
Tendon Muscle

 

As the electrical current travels through the patient and meets resistance it is transformed into heat energy. This causes severe electrical burns along the path it traveled through the body. The electrical injury done to the body can be catastrophic to tissues, organs, bone and muscle.

 

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