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What is an Automated External Defibrillator (AED)?

A defibrillator or AED is a life-saving machine that delivers and electric shock to the heart which when used promptly, in the case of sudden cardiac arrest, can restart the heart.

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How does an AED work?

When someone has a sudden cardiac arrest the heart commonly goes into a state of ventricular fibrillation (VF), a kind of wobbling muscle spasm rather than a proper heart beat which means that blood is not being pumped around the body. While it is in this state applying an electric shock from a defibrillator can restart the heart and help save that persons life.  Performing CPR (cardio pulmonary resuscitation) helps to prolong the period of time that the heart remains in this shockable rhythm until defibrillation is available.

The UK Resuscitation council estimates that there are around 30 000 cardiac arrests in the UK outside of hospital every year. So knowing how to perform CPR and increasing the number of AED's available in public places will directly increase the survival rates of cardiac arrest victims.

The scientific evidence to support early defibrillation is overwhelming; the delay from collapse to delivery of the first shock is the single most important determinant of survival. If defibrillation is delivered promptly, survival rates as high as 75% have been reported. The chances of successful defibrillation decline at a rate of about 10% with each minute of delay.

On all our first aid courses you will be taught the best possible sequence of events to maximise the survival rate of people who have suffered cardiac arrest. This is known as the Chain of Survival. In an ideal world all of the steps would be performed simultaneously, of course if you are by yourself this will not be possible so the most important thing is to call 999 and ask anyone who comes to help you if they can quickly locate and AED in the building while you are performing CPR.

It is estimated that every minute defibrillation is delayed, the chance of survival reduces by 10%!

How do you use an aed?

AEDs are designed to be used by members of the public. They have become widely available, are safe and easy to use, and will not allow a shock to be given to a victim who does not require one.

Whilst there are many different types and manufacturer of AED the fundamentals are the same. When the unit is switched on a voice will talk loudly telling you what to do with clear and simple instructions. Pads are stuck onto the casualty's bare chest and the AED will receive information about the heartbeat which it then analyses to see if a shock can be delivered. If it can the AED will charge itself. No one must be touching the patient when the shock is delivered which typically happens at the press of a button.

Can I use an AED even if I have not been trained?


The UK Resucitation Council is very clear that:

"While it is highly desirable that those who may be called upon to use an AED should be trained in their use, and keep their skills up to date, circumstances can dictate that no trained operator (or a trained operator whose certificate of training has expired) is present at the site of an emergency. Under these circumstances no inhibitions should be placed on any person willing to use an AED.

It is the view of Resuscitation Council UK that the use of AEDs should NOT be restricted to trained personnel. Furthermore, Resuscitation Council UK considers that it is inappropriate to display notices to the effect that only trained personnel should use the devices, or to restrict their use in other ways. Such restrictions are against the interests of victims of cardiac arrest and discourage the greater use of AEDs by members of the public who may be able to preserve life and assist victims of cardiac arrest. This confirms similar advice from the British Heart Foundation."

Whilst anyone can use an AED, it is preferable that people receive training first. It would also be better if more people were trained in CPR, which buys time before defibrillation.

react First aed training courses

All our first aid qualifications include CPR and training in the safe use of an automated external defibrillator or AED.

We have a short,  4 hour, course called Basic Life Support and Safe Use of an AED which covers all the essential, life-saving first aid treatments. This BLS course with AED training gives you the knowledge and the confidence to give prompt, effective treatment to a casualty suffering from cardiac arrest.  

  • In-house AED Training - we send a trainer to your workplace to train your staff onsite
  • Public AED Training courses - we run a programme of public first aid and AED training courses in Central London. Have a look at our calendar for a full list of dates and venues. You can also book and pay for your place online. 

Where can I buy an AED and how much will it cost?

We have found a very good AED supplier to recommend: Wessex Medical. They have over 30 years of experience selling defibrillators and they have strong relationships with all the major suppliers.

If you call them directly on 01722 410 084 you will often get through to Alan, the company owner, who has a wealth of knowledge in this area and will be happy to advise you on what you need and also on how to install and maintain it.  

Alan currently recommends the Radian AED - which comes from Korea and is both reliable and extremely very good value for money at £699+vat.

Or, for those who prefer a known brand, Phillips have a range of AED devices which shouldn't cost you more than £1000+vat.

You also need to factor in the cost of the case it is kept in and what installation costs you may have for this and also if the AED will be connected to a power supply to trickle charge. All in all you should be budgeting about £1000-£1500. You also need a maintenance / service contract. Sometimes the software on the decive needs to be updated, things like the pads will have an expiry date, if any warning lights come on you need to know who to contact.

Read more here:


Download UK Resus Council Adult BLS and AED Guidelines


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