Automated External Defibrillator

What is it?

An automated external defibrillator is a device that uses pads when applied to an unconscious person's chest assesses the heart rhythm.  The device uses pre-programmed algorithms to determine whether or not to deliver a 360 joule shock to the unconscious person. The device uses voice commands and prompts to assist the rescuer in applying the pads correctly and whether or not to start or continue chest compressions as learned in CPR classes. The machine will then prompt the rescuer to push a button and accidentally pushing the button is fairly impossible.

Indication of use

A rescuer would use a automated external defibrillator on a person that has collapsed, like fainting after a sudden lowering of blood pressure or after someone was struck in the head and is now unconscious. Some people have an unknown medical heart condition like Wolff Parkinson's white syndrome or prolonged QT syndrome or Brugada syndrome that for some unexpected reason the heart goes into VT or VF. It is when  VT or VF is present that the machine will deliver a shock and not for any other reason.  If the machine does not detect such rhythms then it will not deliver a shock.  So it is almost impossible to do more harm.   More harm will come to someone if the machine is not hooked up at all.  Simply hooking the machine up to an unconscious person will not harm them.

How to use

Most automated external defibrillators offer pictures on the machine itself in order to use it efficiently.  Generally the pads are placed in such a way as to cause the electrical current to cover the heart.  One pad is placed on the right upper chest and the second is placed on the unconscious persons left side approximately middle of the armpit along the nipple line or just below. It is not necessary to be extremely precise but as long as the pad is placed in this manner it will generate the best possible chance for success.  Then simply turn on the machine and follow the prompts. Most machines are built in this way, easy to use.

Click here to watch a video on how to use an automated external defibrillator

What to look for when purchasing an AED

Ease of use

The device needs to be simple to use by anyone and everyone. It should be so easy to use that someone with no training would be confident to use it.

Protection Plan

This is obvious, the longer the plan, the better.  An automated external defibrillator is an investment and a longer protection plan will protect that investment.  Just make sure the protection plan is all encompassing.

Low cost

The lowest price for the best device. Buy in bulk and negotiate for a lower price. Ask friends and neighbors to buy a device and save.

Personable and assertive voice prompts

When in a situation that is very stressful it is easy to forget what to do.  Having an assertive but friendly voice is important to take away any guess work.  The last thing you need is to question what you are doing, but rather to have the confidence transferred to the rescuer.

CPR prompts

Most devices have prompts to do CPR when it is necessary, but only one device tells the rescuer if the CPR compressions are done properly.  The rescuer can train and become so proficient at CPR, but it is another thing when faced with a life threatening condition and an unconscious person in front of them.  It is easy to forget what to do and how hard to press the chest.  CPR dummies are good, but they don't mimic the real chest very well.  So unless faced with the real thing countless times, to do it right the first time is a daunting task.  To have instant feed back from the device that tells the rescuer that the compressions are done right the first time, is priceless.

Ease of use website

One aspect that often gets neglected is the companies website.  Purchasers often neglect checking the companies website for easy to find information and support.  Although, devices are made well for the most part and have stringent testing.  Problems do happen and when they do it is imperative that information on the website is easily found.

Customer service

Much like an easy to navigate website when problems arise, a company needs a great customer service to back their product.  Red flags would be raised if a company states their product is the best and does not back up their product.  Great customer service is the corner stone of any great business.  If the employees are happy and helpful then you know the company treats their employees with care and that's a winning combination.


What kind of maintenance is required on a device?  Devices may sit for months or years without being used.  So when the time comes to use a device you need peace of mind knowing the device will work.  At the same token wherever the device is located, you don't want to waste an exorbitant amount of time maintaining the device.  a maintenance regime needs to be simple and quick.  Another question to ask yourself is whether the device does a series of self checks and after the self check is it easily seen that the device has a problem?


As more information gets assimilated about CPR and defibrillating changes do occur in the algorithms.  the heart and stroke chapter of your country or regime makes changes annually so the device needs to be upgraded from time to time.  Just like the changes recently in the airway, breathing and circulation (ABC) model to widely adapted compressions, airway and breathing algorithm (CAB).

Top 6 automated external defibrillator companies

1. Zoll

2. Phillips

3. Defibtech

4. Heartsine

5. Physio-control

6. Cardiac science

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