Automated External Defibrillator

Automated External Defibrillator

In June 2016, the Health and Safety Executive published a First Aid Bulletin which made amendments to the workplace First Aid courses. The major change to these courses was the mandatory teaching of the use of an Automated External Defibrillator (AED) to be commenced with effect from January the 1st 2017.

As well as this important development for workplace First Aid courses, the Department for Education (DfE) will shortly be publishing new syllabi for Paediatric First Aid courses; this will be the first time that the Government Department responsible for Early Years will have published syllabi for these courses. In recent months, The First Aid Awarding Organisations’ Forum has been liaising with the DfE to write new units for regulated Paediatric qualifications. As such these have been approved to meet the new, soon to be released syllabi and have come into effect, officially, from January 1st 2017.

We have therefore introduced AED teaching into all of our First Aid courses as standard with the exception of First Aid for Parents and First Aid for Brownies.

We thought we would take this opportunity to explore the purpose of an AED and how to safely use one when trying to save a life.

Did you know?…

If a defibrillator is used and effective Cardio-Pulmonary Resuscitation (CPR)
is performed within 3-5 minutes of a cardiac arrest the chances of
survival increase from
6% to 74%.

What is an Automated External Defibrillator?

An Automated External Defibrillator, also known as an AED or defib, is a portable device that checks the heart rhythm of a casualty and can send an electric shock through the casualty’s heart to try to restore a normal rhythm.

What is an AED used for?

An AED is used to treat sudden cardiac arrest (SCA). SCA is a condition where a heart suddenly and unexpectedly stops beating or beating in a normal rhythm.

A cause of SCA is Ventricular Fibrillation (v-fib). Ventricular fibrillation is the most serious cardiac rhythm disturbance. The lower chambers of the heart called the ventricles quiver and can’t pump the blood any more. This causes a SCA.

When discussing ventricular defibrillation on our courses, we often describe the quivering of the lower chambers of the heart as a plate of jelly, and this helps to demonstrate how this is not good for the casualty’s body and heart.

What does the AED do?

The electric shock that the AED delivers to the heart, stuns the heart to try to stop the abnormal rhythm that the heart is currently suffering from.

The AED cannot shock a flatlining or totally stopped heart, nor can it shock a heart which is in a normal working rhythm, in these circumstances the AED will advise the First Aider continues with CPR if it is needed and will then recheck the heart rhythm after approximately 2 minutes.

How do I know if there is a Public Access Defibrillator (PAD) near me?

Public Access Defibrillators are identified by a sign that the Resuscitation Council (UK) have designed. The sign is closely aligned to the First Aid sign which is widely recognised across the United Kingdom. The AED standard sign is available here. In 2008, ILCOR (International Liaison Committee on Resuscitation) designed a universal AED sign, which has 3 subtle differences to the Resuscitation Council (UK) version, as follows:

  • There is a white cross in the top right corner,
  • There is an arrowhead at the bottom of the flash,
  • The word AED is used in place of defibrillator.

You can view this version of the sign here, although the Resuscitation Council (UK) agrees that it meets legal guidelines, but feels that their design meets the UK needs better. Also, it is not clear how many other countries will endorse the ILCOR version.

How safe is an Automated External Defibrillator to use?

Modern AEDs are very reliable and will not allow a shock to be given to a casualty unless it is absolutely necessary. It is highly unlikely that an AED will cause any harm to a sudden cardiac arrest casualty nor will it cause any harm to a First Aider. There is no need for any specific training to be given as the machine will talk you through the process, although it is a good idea to have the knowledge of how they work.

Are there any safety advice guidelines?

There are some considerations to be aware of as follows:

Casualty’s Wet Chest

Should the casualty have a wet chest, for example they have been profusely sweating or swimming, the chest should be dried prior to the AED pads being applied to the chest, ensuring that the pads adhere to the chest properly. Also, ensure that you have dried the area of the chest between the pads to prevent the electricity from ‘arcing’ across the chest.

Excessive Chest Hair

A particularly hairy chest will prevent the AED pads from adhering effectively to the casualty’s chest as well as interfering with the electrical contact. Only shave a chest if the casualty has excessive chest hair and even then only spend the minimal amount of time as possible to do this. However, do not delay defibrillation if there is no razor available, although there should be one in the Defibrillator pack.


Care should be taken to ensure that any jewellery, for example a necklace, is not placed under the defibrillator pads. If this should happen the electric shock that is supposed to go through the heart, will actually conduct through the jewellery and burn the casualty. You do not need to remove body piercings as long as you do not place the pads over these.

Medication Patches

Some casualties may be wearing a patch which delivers medication to them. This could be a nicotine patch, or in the case of some heart patients a ‘Glyceryl Tri-Nitrate’ (GTN) patch. If electricity passes through these types of patches, the patch could explode, therefore you should remove any visible medication patches.

Implanted Devices

Usually any implanted devices, for example a pacemaker or defibrillator, are implanted on the left hand-side of the casualty’s body just under the collar bone. You can usually see or feel them under the skin when the chest is exposed, and there may well be a scar. Should they be on the left hand side as described above they will not be in the way of the AED pads, however if they are in any other position, you should avoid placing the pads directly on top of these devices.

Highly flammable environments

The AED could potentially create a spark when delivering the shock to the casualty’s heart. With this in mind the AED should not be used in a highly flammable atmosphere, for example in the presence of petrol fumes.

Other Considerations

A defibrillator should not be used when the casualty is having a seizure, and the First Aider should ensure that any vehicle engines and/or vibrating machines are switched off wherever possible.

Do NOT delay defibrillation because the casualty is laid on a wet surface or something that is metal, as long as the chest is dry it is safe to deliver the shock.

How do we use a Defibrillator?

So, we have spent a while discussing how the AED works and the safety considerations, we should conclude this blog with the instructions of how to use.

In fear of repeating ourselves, DO NOT delay in using the defibrillator if there is one available, however should you be alone or not have access to a Defibrillator, you should commence CPR immediately.

When the Defib arrives:

  • Switch on the defibrillator immediately and follow the voice prompt,
  • Attach the leads to the AED if necessary,
  • Attach the pads to the casualty’s bare chest, having assessed whether the chest needs to be dried and/or shaved due to excessive hair, and observing for signs of jewellery, medication patches and/or implanted devices as stated above,
  • Peel the backing off one pad at a time and place, where indicated, firmly onto the chest:
    • Place one pad below the casualty’s right collarbone,
    • Place the other pad around the casualty’s left side over the lower ribs,
    • DO NOT remove the pads if the diagram shows you have laid them the wrong way round as the AED will still work,
  • While the AED analyses the heart rhythm – stop CPR and ensure that no one touches the casualty.

If a shock is indicated, deliver shock:

  • Ensure that no one touches the casualty,
  • Push the shock button as directed, if you have a fully automated defibrillator, it will deliver the shock automatically,
  • Immediately restart CPR at a ratio of:
    • 30 Chest Compressions (at a rate of 120 per minute) to
    • 2 Rescue Breaths.
  • Continue as directed by the defibrillator voice commands.

If a shock is NOT indicated, continue CPR:

  • Immediately restart CPR at a ratio of:
    • 30 Chest Compressions (at a rate of 120 per minute) to
    • 2 Rescue Breaths.
  • Continue as directed by the defibrillator voice commands.

N.B. if you are dealing with a child, pay particular attention to the defibrillator pads that you have.

Paediatric Specific Defibrillator Pads:

  • Peel the backing off one pad at a time and place, where indicated, firmly onto the chest:
    • Place one pad in the centre of the child’s chest,
    • Place the other pad in the centre of the child’s back.

However, they may also be designed to use as per the adult pads. If using adult pads you should use them as per the description above.

For more information on the use of AEDs, why not book a First Aid course where we will take you through the use of them and you will get the opportunity to try using one on a CPR manikin.

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