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A defibrillator (sometimes called a ‘defib’, or AED (if it’s an automated external defibrillator) can save someone's life if they have a cardiac arrest. The sooner you use a defibrillator, the greater the person's chances of survival.

Dial triple zero (000) and ask for an ambulance if someone has had a cardiac arrest.

What is a defibrillator?

A defibrillator is a device that uses electricity to re-start the heart or shock it back into its correct rhythm.

It is used when someone has a sudden cardiac arrest. This is when the heart suddenly stops pumping.

The defibrillator analyses the heart rhythm and decides whether an electric shock is needed.

Each year, more than 30,000 Australians suffer a cardiac arrest. If it happens outside a hospital, their chances of surviving are less than 1 in 10.

Giving the person immediate cardiopulmonary resuscitation (CPR) and using an AED early on can greatly increase their chances of survival. The most important thing is to use the AED quickly.

What are the different types of defibrillator?

There are several different types of defibrillator, and they work in different ways.

Automated external defibrillators (AEDs): These are found in public places and can be used by anybody in an emergency. They guide you through each step of the process. They won’t give the person an electric shock unless it’s necessary, so you can’t harm someone by using an AED. Some models ask you to press a button to deliver the shock, and other models deliver the shock automatically.

Manual defibrillators: These are used by health professionals — for example, in an ambulance or emergency department.

Implantable cardioverter defibrillators (ICDs): These are defibrillators that are surgically placed inside the body. They are designed for people who are at high risk of a life-threatening heart rhythm problem (such as those who may have had a recent heart attack or who have certain medical conditions).

Wearable cardioverter defibrillators (WCDs): These rest on the body. They are usually used by people who are recovering from a heart attack or who are waiting for a heart transplant.

Where can I find the nearest defibrillator?

AEDs are often found in large public places, including:

  • hospitals
  • community centres
  • workplaces
  • schools
  • shopping and business centres
  • sporting clubs and gyms
  • public libraries
  • zoos

They are usually in a foyer or staff room in the case of smaller facilities and are clearly marked. St John Ambulance Australia has an iPhone app, Resuscitate, to help you find publicly accessible defibrillators that are near you. You can download the app from the iTunes store.

When to use a defibrillator

You can use a defibrillator whenever CPR is needed. A person needs CPR if they are unresponsive and not breathing normally.

Remember, time is crucial. If someone is unresponsive and not breathing, call an ambulance on triple zero (000), start CPR and use a defibrillator as soon as possible.

How to use an automated external defibrillator (AED)

Anyone can use an AED. The device will tell you what to do. AEDs must be used in conjunction with CPR.

Make sure the area around the person is clear. Don’t touch the person while you are using the AED because this could interfere with how it reads the person’s heart.

If necessary, the AED will tell you where to put electrodes (pads) on the person’s body. The device may deliver more than 1 shock.

The AED may instruct you to continue CPR after the shock. Continue CPR until the ambulance arrives and a paramedic takes over.

Buying an AED

If you want to buy an AED for your organisation, make sure you buy it from an Australian supplier and that it is approved by the Therapeutic Goods Administration (TGA).

Display the AED so it is visible and accessible to all users, and make sure people know where it is. It’s a good idea to train people how to use it.

It is important to maintain the AED regularly according to the manufacturer’s instructions.

More information

You don’t need training to use an AED, but first aid training will increase your confidence. To find a first aid training course near you, contact St John First Aid Training on 1300 360 455.

You can view defibrillators for sale on the St John Ambulance website.

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Last reviewed: January 2021

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