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In Australia, sudden cardiac arrest (SCA) is a leading cause of death that can affect anyone, anywhere, at any time— a SCA is not gender or age specific.


Estimates suggest around 15,000 people die unexpectedly in Australia from a SCA every year—that’s around 10% of all Australian deaths every year (153,000). 1


Fortunately, defibrillation using an automatic external defibrillator (AED) dramatically improves survival rates if applied in minutes. Defibrillators do save lives, and this makes them the most powerful tool a First Aider can use.




But what is an AED, and how do they save a life? Are they dangerous? Do you need to be first aid trained?


St John Ambulance is the leading retailer of AEDs—we install and train in their use as well—so we’re often asked these questions. In this article, we’ve answered the most common questions we hear about AEDs.


1. What does ‘AED’ stand for?

‘AED’ stands for Automatic External Defibrillator—also known as a defibrillator or ‘defib’.


2. What is an AED?

An AED is an accurate and easy-to-use computerised medical device. An AED analyses a person’s heart rhythm and recognises a rhythm that requires a shock.


If you use an AED within the first few minutes of a SCA, it can increase the survival rate to as high as 70%. Therefore, it is vital that more people become aware of what AEDs are, how to find them and how to use them.


3. What is defibrillation?

Defibrillation is the process of attempting to restore the heart’s normal rhythm. A SCA is associated with a disturbance of the electrical activity in the muscles of the heart’s larger pumping chambers.


4. What does an AED do?

An AED delivers a set amount of electrical shock to the heart after it analyses that the heart’s rhythm is not normal. The AED determines whether a shock is required to the heart via the adhesive electrode pads attached to the patient’s chest. The electric shock will hopefully restore the heart’s normal electrical rhythm.


5. How does the AED work?

An AED delivers a set amount of electrical shock to the heart after it analyses the heart rhythm. It determines whether a shock is required to the heart via adhesive electrode pads attached to the patient’s chest. The shock then interrupts the chaotic rhythm of the heart and gives the heart the chance to return to its normal pumping rhythm.


6. How do I use an AED?

Anyone can use an AED as they are very easy to operate. It is just a matter of opening the case, pushing the On button, and it will instantly give you voice prompts to follow. It doesn’t skip ahead, and will keep repeating the instruction until each step has been completed, making it a reassuring guide in what can be a stressful situation.


In an ideal situation, CPR should be done while someone else is retrieving the AED. If CPR is done as soon as possible, there is a better chance of keeping the heart in ‘fibrillation’ or a ‘shockable rhythm’.





Defibrillators give audio instructions on where to position the pads. Some AEDs  can even show with small display screens.

Product Pictured: Defibtech LifeLineView 


7. Is an AED dangerous to use?

No. The AED assesses the status of the person’s heart beat. If the heart beat is normal, the AED will say ‘do not shock’. If it is not normal, the device will advise by a voice command to press the shock button. The AED will not allow a shock to be given when none is needed.


8. Do I need training to use an AED?

No. Anyone can use an AED. The voice prompts are designed for beginners and will instruct you on exactly what to do—from reminding you to call Triple Zero (000), to counting out the CPR rhythm.

However, St John encourages first aid and AED training as it increases your confidence and preparedness in using an AED. It helps people understand where the AED fits in to the DRSABCD process and the Chain of survival.


Training in the use of an AED can save precious seconds that might be wasted in opening and positioning the AED, which is why we recommend you complete First Aid training and do regular refreshers.


9. Can AEDs be used on children?

Yes. Standard adult AED pads are used on children older than 8 years. For children under 8, special infant/child pads or ‘keys’ are available that adjust the electrical current delivered by the AED, to be suitable for a child.


In an emergency, if an AED with adult pads is the only device available, you should definitely consider using it. The use of an AED is not recommended on children aged less than 1 year.


10. Can AEDs be used on pregnant women?

Yes. It is safe to use an AED on a pregnant woman. Treat a pregnant woman the same any patient who is not responding or not breathing


St John Ambulance Queensland is passionate about empowering individuals and believes first aid capability is an essential skill that everyone should have. That’s why we sell variety of AEDs ideal for your needs and budget. We have already helped hundreds of businesses find the right AED. Let us help you. 


Specially priced online packages are also available. Click here to view online deals.



Share your AEDs life-saving power with others.

The St John Public Access Defibrillator (PAD) register is a national register to record the details and location of defibrillators. The iPhone app, Resuscitate, makes it easier to find publicly accessible defibrillators nearest to you. It reduces the time to gain access to defibrillation by using the built-in Google Maps function.


Register your AED at



1 -Heart Foundation,, accessed 11 May 2017.

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