What is an AED?

Posted by chris

What is an AED?

Defibrillation is the delivery of electrical energy to the heart during an abnormal rhythm or very rapid erratic beating of the heart known as Ventricular Fibrillation (VF).  Electrodes placed on the victim’s chest to serve as the conduit for delivering a measured electrical shock to the heart to restore natural rhythm.


·        The first use of an external defibrillator on a human was in 1947 by Claude Beck.

·        The portable version of the defibrillator was invented in the mid-1960s by Frank Pantridge in Belfast, Northern Ireland, a pioneer in emergency medical treatment

How does it work?

·        Automatic external defibrillators, or AEDs, are small computerized devices that analyze heart rhythms and provide the shock needed for defibrillation.

·        Through electrodes placed on a patient’s chest a processor inside the AED analyzes the victim’s heart.

·        The machine will not shock unless it is necessary; AEDs are designed to shock only when VF, a common cause of cardiac arrest, is detected.

·        After the AED analyzes the heart rhythm and determines a shock is required, an electric current is delivered to the heart through the victim’s chest wall through the adhesive electrode pads.

·        The shock delivered by a cardiac defibrillator interrupts the chaotic rhythm and allows it to return to normal.


What’s the difference?

With CPR alone, the chance of survival after sudden cardiac arrest is less than 5%; when CPR is combined with the use of a cardiac                          defibrillator within the first few minutes, the chance of survival can increase dramatically to more than 75%.

Having an AED on hand gives victims of sudden cardiac arrest the best chance of survival until paramedics arrive and take over care. 


For every minute that passes following a cardiac arrest, the chances of survival without defibrillation decrease by 10%. Yet a recent 2017 UK YouGov poll showed that a worryingly high 7 out of 10 people would not be confident using a public defibrillator.

Here are 5 of the main fears you really shouldn't have about using a public defibrillator...

1. Fear of the Unknown...                                                                                                                                                                 

For those that have never been trained to use a defibrillator, or even seen one up close, the thought of grabbing the nearest one and "giving it a go" wouldn't cross their mind. "What if I'm not allowed to use it?", "What if I hurt someone?", "What if I hurt MYSELF?", "I don't know how it works!".                                                                                                                                                                                                                                                                      But fear not! Defibrillators are remarkably "intelligent" pieces of equipment that have been designed for ANYONE (that means you!) to use in an emergency situation. An Automated External Defibrillator (AED) will actually "talk" to you and guide you through how to use it. It really couldn't be easier!

2. Fear of causing the casualty harm...



The same 2017 YouGov poll showed that huge 62% of people believed a defibrillator would potentially cause a casualty harm.

As previously mentioned, the defibrillator will "decide" when a shock is required. If the casualty's heart is still beating, the defibrillator won't allow a shock even if you push the "shock" button.

3. Fear of being trained...

It may sound odd but a lot of people worry that if they learn how to use a defibrillator, they will be taking on more responsibility that they don't want to shoulder. Others aren't aware that anybody can be trained to use a defibrillator as part of a First Aid course, they assume it can only be used by medical professionals. In actual fact, training isn't a requirement to use a defibrillator (although it is highly preferred). They are available for all bystanders to use when required regardless of training.


If defibrillation is provided within the 1st minute of a cardiac arrest, survival rates increase to 90%.


These views could easily be changed with raised awareness, and education at an early age i.e school. The U.K is a long away behind other European countries (particularly in Scandinavia). In Sweden alone there are approximately 5,151 public defibrillators and 3 million people are trained to administer CPR through mass courses in schools and workplaces (figures from the Defib Shop). The general attitude towards CPR and defibrillation in the UK needs to change dramatically.

4. Fear of being "sued"...


This seems to be a big fear within First Aid in general. With the current blame culture we live in, a large number of people are put off by the thought of being sued by a casualty. This is a big misconception that really holds back the volume of people in the UK that get trained in basic First Aid and using a defibrillator.

Nobody in the UK has ever been sued for attempting CPR. In 2015, the government introduced the ‘Social Action, Responsibility and Heroism (SARAH)’ act to protect those performing “acts of heroism”.

Again, we have to educate from an earlier age to encourage people to provide Basic Life Support and make the above information common knowledge.

5. Fear of leaving the casualty...

Although carrying our CPR whilst someone gets a defibrillator is highly preferable, it is more important to call 999 and provide quick defibrillation if a casualty has stopped breathing. This may mean leaving the casualty to find the closest defibrillator. If defibrillation is provided within the 1st minute of a cardiac arrest, survival rates increase to 90%.

AED's are becoming much more common in public areas such as supermarkets, train stations, shopping centres and airports. You should familiarise yourself with the locations of defibrillators in your local area where possible.

So to finish off, here are a few facts from the Defib Shop regarding CPR & defibrillation that I hope will highlight the importance of facing our fears!


  •  Approximately 30,000 out of hospital cardiac arrests happen every year in the U.K.For further information about CPR, First Aid and Defibrillator training courses visit www.lubasmedical.com.
  • Without immediate treatment 95% of sudden cardiac arrest victims will die
  • If a defibrillator is used & effective CPR is preformed within 3-5 minutes of a cardiac arrest, survival chances increase 6%-74%
  • Only 22% of people in the UK would be confident providing CPR to a stranger 
  • Approximately 80% of out of hospital cardiac arrest happen at homee
  • The reason so few people survive sudden cardiac arrest is due to defibrillation not being provided quickly enough after they have collapsed 


For further information about CPR, First Aid and Defibrillator training courses visit www.lubasmedical.com.

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