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An AED trainer is a training device designed to help people practise using an Automated External Defibrillator, AED, during a simulated cardiac arrest.
It looks and operates in a similar way to a real AED but does not deliver an electrical shock.
During practical first aid training, learners can switch the trainer on, listen to its instructions, position the electrode pads, stand clear during simulated heart-rhythm analysis and practise delivering a simulated shock.
Using an AED trainer alongside CPR manikins allows learners to experience the complete sequence of responding to a cardiac arrest without the risks associated with using a live defibrillator for training.
Most importantly, learners discover just how straightforward an AED is to use.
What Is an AED?
AED stands for Automated External Defibrillator.
A real AED is designed to analyse the heart rhythm of someone in cardiac arrest and determine whether defibrillation is appropriate.
If a shockable rhythm is identified, the device will advise the rescuer to deliver a shock or, depending on the type of AED, deliver it automatically.
The purpose of that shock is to help restore an organised heart rhythm in certain cardiac arrests.
Current Resuscitation Council UK guidance states clearly that anyone can use an AED. Formal training is not required before somebody can use one in an emergency. Resuscitation Council UK
That raises an obvious question.
If anybody can use a defibrillator, why do we practise with AED trainers?
Why Practise With an AED Trainer?
There is a significant difference between understanding that an AED is easy to use and having actually handled one.
Imagine finding somebody collapsed at work.
You have called 999 and started CPR.
Another person arrives carrying the AED.
For the first time in your life, you now need to:
Open the case.
Switch the AED on.
Expose the casualty’s chest.
Remove the pads.
Work out where they go.
Attach them correctly.
Follow the voice instructions.
Make sure nobody touches the casualty during analysis.
Possibly deliver a shock.
Restart CPR immediately afterwards.
An AED is designed to guide you through this process, but doing something for the first time during a genuine cardiac arrest is very different from having practised it beforehand.
An AED trainer gives you that practice.
Resuscitation Council UK says no specific training is required to use an AED, but its community CPR and AED training standards include demonstrating how the device works, pad positioning, understanding its prompts, standing clear during analysis and delivering a shock when advised. Resuscitation Council UK
The two messages are not contradictory.
You do not need training to use an AED in an emergency.
But:
Practical training can help you become familiar with what you will need to do.
Is an AED Trainer a Real Defibrillator?
No.
An AED trainer is designed specifically for training and simulation.
Although it may look very similar to a real AED, it cannot deliver a therapeutic electrical shock.
That allows learners to practise safely on CPR manikins and work through different simulated cardiac-arrest scenarios.
Depending on the model, an AED trainer may reproduce many of the functions and prompts associated with a live AED.
For example, it may simulate:
- Switching the AED on
- Voice instructions
- Attaching electrode pads
- Heart-rhythm analysis
- A shock-advised scenario
- A no-shock-advised scenario
- Simulated shock delivery
- Instructions to continue CPR
- Reassessment after a period of CPR
Training models differ, so the exact controls and prompts will depend on the device being used.
What Happens During AED Training?
AED practice should form part of the wider response to cardiac arrest rather than being taught as an isolated skill.
A learner might begin with a casualty who has collapsed.
They check for danger and response.
Once the casualty is identified as unresponsive, 999 should be called without delay. Breathing is assessed while waiting for the call to be answered.
If the casualty is unresponsive and not breathing normally, CPR begins.
Another rescuer may then bring the AED.
At this point, the learner has to incorporate the defibrillator into an emergency that is already happening.
This is much more realistic than simply placing an AED trainer on a table and asking somebody to switch it on.
Using an AED Trainer Step by Step
Although different AEDs vary slightly, practical training generally follows the same principles.
1. Continue CPR
CPR should continue while the AED is being brought to and prepared for the casualty.
Do not unnecessarily stop chest compressions just because the AED has arrived.
Where more than one rescuer is present, one person can continue CPR while another prepares the AED and attaches the pads.
Resuscitation Council UK emphasises minimising interruptions to chest compressions during AED use. Resuscitation Council UK
2. Switch the AED On
Open the AED and switch it on.
Some real AEDs activate automatically when their case or lid is opened. Others have a clearly marked power button.
Once activated, listen to the instructions.
One of the most useful things learners discover during AED training is that the device tells you what to do next.
3. Expose the Casualty’s Chest
AED pads need to be attached to the casualty’s bare chest.
Clothing must therefore be removed or cut away sufficiently to allow correct pad placement.
Training gives learners an opportunity to discuss some of the practical issues that may occur when exposing and preparing the chest.
These situations can feel much less daunting once they have been discussed and practised.
4. Attach the AED Pads
Remove the backing from the electrode pads and attach them firmly to the casualty’s bare chest.
The pads themselves normally show where they should be positioned.
For an adult, the usual placement is one pad on the upper right side of the chest, below the collarbone, and the other on the left side of the chest below the armpit.
Correct pad placement is something learners can physically practise using an AED trainer and CPR manikin.
5. Allow the AED to Analyse
Once the pads are attached, the AED will analyse the casualty’s heart rhythm.
Nobody should touch the casualty while the device is analysing.
The rescuer should clearly tell everyone to stand clear and visually check that nobody is in contact with the casualty.
This is another useful training point.
Learners need to develop the confidence to communicate with the other people around them rather than concentrating only on the machine.
6. Deliver a Shock If Advised
If the AED identifies a shockable rhythm, it will instruct the rescuer accordingly.
With some devices, the rescuer presses a flashing shock button.
Fully automatic AEDs can deliver the shock automatically after warning rescuers to stand clear.
An AED trainer simulates this process without delivering real electrical energy.
The learner can therefore practise checking that everyone is clear before following the device’s instruction.
7. Restart CPR Immediately
CPR should restart immediately after the simulated shock.
Do not pause to see whether the shock has “worked”.
The AED will continue guiding the rescuer and will reassess the rhythm at appropriate intervals.
If no shock is advised, CPR should also resume immediately when the device instructs you to do so. RCUK’s community training standards specifically include practising the response to a no-shock-advised instruction. Resuscitation Council UK
Can an AED Shock Someone Who Does Not Need It?
This is one of the most common concerns learners have.
A real AED analyses the casualty’s heart rhythm before deciding whether defibrillation is appropriate.
The rescuer does not make that clinical decision.
Resuscitation Council UK states that AEDs are designed so they will not shock somebody who does not require a shock. Resuscitation Council UK
That is why an untrained member of the public should not be frightened to use one.
Switch it on and follow its instructions.
Do You Need Training Before Using an AED?
No.
This point deserves to be extremely clear.
You do not need an AED certificate or previous AED training before using a defibrillator in an emergency.
Resuscitation Council UK’s 2025 Adult Basic Life Support guidance states that anyone can use an AED and recommends that AED signage makes clear that no training is required. Resuscitation Council UK
If somebody is in cardiac arrest and an AED is available, use it.
Do not stand back because the only person who attended the first aid course is not there.
Do not wait for somebody who has an AED certificate.
Do not assume you might make the situation worse.
Turn the AED on and follow its instructions.
Why Train People If Anybody Can Use an AED?
Because being allowed to do something and feeling confident doing it are two different things.
Someone seeing an AED for the first time during a cardiac arrest may worry about:
Where to put the pads.
Whether they could shock the casualty incorrectly.
Whether everybody needs to stand back.
When to stop CPR.
When to restart CPR.
Whether the AED can be used if the casualty is wet.
What happens if there is excessive chest hair.
What happens if the AED says no shock is advised.
Practical training allows these questions to be answered before the emergency occurs.
It also allows the learner to make mistakes safely.
That is one of the major benefits of using an AED trainer.
AED Training Should Include CPR
Defibrillation is only one part of the response to cardiac arrest.
Current Resuscitation Council UK guidance emphasises early recognition, calling 999, starting CPR and using an AED as soon as possible. Resuscitation Council UK
AED practice should therefore be integrated with good-quality CPR.
For an adult, chest compressions should be delivered at:
100 to 120 compressions per minute
to a depth of:
At least 5 cm but no more than 6 cm.
If the rescuer has been trained and is able to give rescue breaths, adult CPR normally uses:
30 chest compressions followed by 2 rescue breaths.
Someone who has not been trained to provide rescue breaths should perform continuous chest compressions.
Our article on the Seven Steps of CPR explains the complete sequence in more detail and is a useful companion to this guide.
Why Minimising Interruptions Matters
An AED does not replace CPR.
One of the most important skills during practical AED training is learning how to introduce the device while interrupting chest compressions as little as possible.
When several rescuers are available, this becomes a team activity.
One person can continue chest compressions while another opens the AED and prepares the pads.
Roles can then change as rescuers become tired.
The device will tell rescuers when they need to stand clear for rhythm analysis and, if required, shock delivery.
RCUK’s community training standards specifically emphasise continuing CPR while the AED is being prepared and applied wherever possible. Resuscitation Council UK
This is difficult to appreciate fully from reading instructions.
It makes much more sense when learners practise it.
What About a Wet Casualty?
Water and defibrillation naturally cause concern.
If the casualty’s chest is wet, quickly dry the chest sufficiently for the AED pads to stick properly.
Do not delay defibrillation unnecessarily by trying to make the casualty completely dry.
The priority is good pad adhesion and safe use of the AED.
Training scenarios allow an instructor to discuss situations such as swimming pools, wet environments and drowning without learners having to work them out for the first time during an emergency.
What About Excessive Chest Hair?
AED pads need good contact with the skin.
If excessive chest hair prevents the pads from sticking properly, it may be necessary to remove enough hair to achieve good pad contact.
Many AED kits include a razor for this purpose.
Do not routinely shave every casualty.
Only remove hair if it is preventing effective pad adhesion, and avoid unnecessary delays.
What Happens If the AED Pads Are Put in the Wrong Place?
The pictures printed on AED pads should be followed whenever possible.
Correct positioning helps the electrical current travel effectively through the chest.
If the pads have accidentally been placed the opposite way around but are both firmly attached in appropriate positions, do not waste valuable time removing and replacing them simply because they are reversed.
The priority is minimising interruptions and delivering defibrillation when appropriate.
AED training gives learners the opportunity to practise pad positioning repeatedly until it becomes familiar.
What Does “No Shock Advised” Mean?
This phrase can confuse learners.
If the AED says:
“No shock advised”
it does not necessarily mean the casualty is recovering.
It means the AED has not identified a heart rhythm that should be treated with a shock at that moment.
If the casualty remains unresponsive and is not breathing normally, restart CPR immediately and continue following the AED instructions. Resuscitation Council UK
The AED will reassess the heart rhythm later.
This is one of the most useful scenarios to practise with an AED trainer because learners quickly understand that the device does not always advise a shock.
Can You Practise With a Real AED?
Training should be carried out using equipment intended for training rather than deliberately attempting to operate a live AED on another learner.
An AED trainer allows realistic practice without delivering therapeutic electrical energy.
Training devices also normally use reusable training pads and can be configured to create different scenarios.
For organisations with their own AED, it can be particularly useful for staff to become familiar with the type of device they are likely to encounter.
In healthcare settings, RCUK quality standards go further and recommend that defibrillator training equipment matches the model used in clinical practice where appropriate. Resuscitation Council UK
Is Every AED the Same?
No.
Different manufacturers produce different AED models.
Some have a power button.
Others activate when the lid opens.
Certain devices use a shock button, while fully automatic models can deliver the shock automatically after warning everyone to stand clear.
Voice prompts, screens, pad connections and carrying cases also vary.
The underlying principles remain similar:
Switch it on.
Attach the pads.
Listen to the AED.
Stand clear when instructed.
Deliver the shock if instructed.
Restart CPR immediately.
Practical training helps people understand these principles rather than memorising one particular machine.
Can AED Trainers Be Used With Children?
Many AED training devices can simulate paediatric defibrillation, although the available functions depend on the particular trainer.
Real AED use in children involves additional considerations, including the child’s age, pad size and whether the AED has a paediatric mode or attenuated pads.
For this reason, paediatric AED practice should form part of appropriate paediatric first aid or resuscitation training rather than assuming the adult procedure can simply be copied without modification.
Our Paediatric First Aid training gives learners practical experience of responding to emergencies involving babies and children.
What Should You Learn From an AED Training Session?
By the end of practical AED training, a learner should be more comfortable with the entire process rather than simply knowing where the power button is.
They should understand how an AED fits into the cardiac-arrest response, including recognising the emergency, calling 999, performing CPR and introducing the defibrillator with minimal interruption.
Learners should also understand that:
Anyone can use an AED.
The AED decides whether a shock is appropriate.
CPR continues alongside AED use.
Nobody should touch the casualty during rhythm analysis or shock delivery.
A no-shock-advised message does not automatically mean the casualty has recovered.
CPR should restart immediately when instructed.
Most importantly, they should leave training more willing to act.
An AED Trainer Builds Familiarity Before the Emergency
An AED trainer cannot reproduce the pressure of a genuine cardiac arrest.
It can, however, remove much of the uncertainty surrounding the equipment.
Instead of seeing a defibrillator as an unfamiliar medical device, learners discover that it is designed to help them.
They have already opened one.
They have attached the pads.
They have heard the prompts.
They have practised standing clear.
They have delivered a simulated shock.
They have restarted CPR.
If they ever need to use a real AED, the situation will still be stressful, but the equipment itself should feel much less unfamiliar.
That is the real value of practical AED training.
Learn CPR and AED Skills With First Aid and Safety Training
Reading about an AED trainer explains how the equipment works, but practical training gives you the opportunity to use it alongside CPR in realistic emergency scenarios.
First Aid and Safety Training uses practical CPR and AED exercises to help learners understand not only what to do, but how the different parts of a cardiac-arrest response work together.
Remember, however, that you do not need to have completed AED training before using a real defibrillator in an emergency.
If somebody is unresponsive and not breathing normally:
Call 999, start CPR and use an AED as soon as one becomes available.
Switch the AED on and follow its instructions.
You can explore our first aid training courses, book a first aid course or contact First Aid and Safety Training to discuss practical CPR and AED training for your workplace or organisation.
You can also find First Aid and Safety Training on Google and see our business information and customer reviews.
