AEDs, or public defibrillators, are designed to be used by anyone. Try to stay calm and follow the directions that the device gives you.

Someone holding the paddles for an AED that show placement. Share on Pinterest
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A defibrillator is an emergency medical device that delivers an electric shock to the heart. The shock can bring a heart out of a potentially fatal heart rhythm and back into a normal heart rhythm.

A defibrillator can save the life of a person who is experiencing cardiac arrest.

Automated external defibrillators (AEDs) are defibrillators carried by first responders or available for use in medical facilities and other public locations.

Call emergency services

AEDs can be a life saving device, but it’s important to make sure that emergency services arrive as soon as possible. If you’re utilizing the AED, ask another bystander to call for an ambulance.

If no AED is avaliable, you can start CPR chest compressions.

AEDs will talk you through how to use them, so follow the recorded instructions closely. The machine reviews the heart rhythm of the person experiencing cardiac arrest and determines if a shock is needed.

An illustrated guide on how to use an AED during a cardiac emergency.Share on Pinterest
Illustrated by Jason Hoffman

To use an AED:

  1. Turn on the AED and follow the voice prompts.
  2. Remove all clothing and jewelry covering the chest of the person in need of help.
    • If necessary, wipe the chest dry.
    • Any metal jewelry in the chest area, including nipple piercings, will also need to be removed before the AED shock is delivered.
  3. Peel away the backing from the pads and attach them to the person’s bare chest following the illustration on the pads.
  4. Plug the pad connector into the AED, if necessary.
  5. The AED will check to see if the person needs a shock and tell you when to give one. While the AED is analyzing, make sure no one is touching the person.
  6. Begin or resume CPR if no shock is needed. If a shock is needed,
    • make sure no one is touching the person
    • press the “Shock” button
    • immediately resume CPR
  7. Continue CPR until emergency medical personnel arrive.

AED machines that use sticky pads have a button on the machine that you push to deliver the shock. Machines that use paddles have a button on each paddle. You’ll push both buttons at the same time to deliver the shock.

AED pad placement on a flat chest

AEDs have two paddles or sticky pads. They are placed on the chest during use.

One pad or paddle is placed below the person’s right shoulder, and the other below the person’s left nipple (and heart).

On a full chest

The AED pad or paddle should be placed below any breast tissue on the person’s left side (below the heart).

When the person experiencing cardiac arrest has a larger chest, you might need to lift the left breast before you begin. You can lift the breast with one hand and then place the left pad or paddle underneath it.

Bras may contain metal and should be removed before AED use.

On a child

Pediatric pads are smaller AED pads designed for use on children between 1 and 8 years old. These child-sized pads can be placed just as adult pads would be.

If pediatric pads aren’t available, you can place one standard pad on the center of the child’s chest and the other on the center of the child’s back.

It’s not safe to use a defibrillator on children younger than 1 year.

Next steps

CPR compressions are the next step after a defibrillator shock. CPR will be given for another 2 minutes.

If the person experiencing cardiac arrest still doesn’t have a pulse, it might be appropriate to deliver another defibrillator shock. The AED machine will read the person’s heart rate and decide whether to shock.

You can learn more about using a defibrillator by reading the answers to some common questions.

Should I do CPR or use a defibrillator first?

You should use the AED the moment it’s available. Every second counts when someone’s heart has stopped.

In an ideal world, you’ll have people around you to assist in calling for help or getting the AED when someone appears to be in cardiac arrest. However, if you’re alone, follow these guidelines:

  1. Check for responsiveness.
  2. Shout for someone nearby to call 911.
  3. Send someone to get AED (or get it yourself).
  4. If there’s a pulse but abnormal breathing:
  5. If there is NO pulse and NO breathing, that is when the AED is used.

Can you use CPR and a defibrillator?

Yes. CPR and defibrillators are both important tools in emergency medical response. Both can be used in response to a cardiac arrest. It might be necessary to use both together to revive someone who has experienced cardiac arrest.

Can an untrained person use a defibrillator?

Yes. AEDs are meant to be used by people without medical experience. The machine will speak to you with recorded instructions that will guide you through the process.

The goal of AEDs is to have quick access to defibrillators. This can double or triple the survival rates for cardiac arrests. Training in how to use AEDs is available, ask at your local community health clinic or hospital for more information.

What happens if you use a defibrillator on someone who doesn’t need it?

The defibrillators that are available for general use analyze a person’s heart rate before delivering a shock. These machines will not deliver a shock if one isn’t needed.

This means it’s very difficult to shock someone who does not need it or to harm someone by using a defibrillator unnecessarily. As a rule, if someone is nonresponsive, not breathing, and doesn’t have a pulse, it’s best to use a defibrillator unless a 911 operator tells you otherwise.

When should you not use a defibrillator?

Anyone who looks like they need CPR can probably be treated with an AED. If a person isn’t breathing, is unresponsive, and has no pulse, it’s a good idea to use a defibrillator if there’s one available.

You can use a defibrillator to treat cardiac arrest even when a person has features such as scars or tattoos on their chest or uses an implantable device such as a pacemaker. Any metal jewelry will need to be removed before AED use, including nipple piercings or subdermal piercings.

AEDs are not designed to be used on children under 1 year old.

Defibrillators are medical devices that can save lives when someone experiences a cardiac arrest. Together with CPR, they can help restart a normal heart rhythm.

The defibrillators you see in some public areas are called AEDs and are designed for use by people without medical training. Once the AED pads are placed on a person’s chest, these machines can detect a heart rate and decide if a shock is needed.

Follow the instructions that the AED device gives you after you turn it on.