First Aid

What is AED in First Aid? – A Detailed Overview

Ricky Kambray
Ricky Kambray

While sudden cardiac arrest is a leading cause of death worldwide, and early defibrillation using an AED can significantly improve survival chances, it’s no surprise that people are looking for an appropriate answer to the question, What is AED in first aid?

An Automatic External Defibrillator (AED) is a medical device employed in first aid to assist in the resuscitation of a person experiencing sudden cardiac arrest. It operates by analysing a person’s heart rhythm and, if necessary, administering an electric shock to the heart. 

This write-up will illustrate everything you need to know about AED, including its importance, types, usage and other required information.

Now, let’s dive into the details without further adieu.

Close-up of First aid kit with AED emergency equipment

Automated External Defibrillator (AED)

Automated External Defibrillator, popularly known as AED is an integral part of the chain of survival. It is a medical device applied to treat sudden cardiac arrest (SCA). It monitors the heart’s rhythm and, if required, delivers an electrical shock, known as defibrillation, to assist the heart in reestablishing an effective rhythm. 

Now the question is, what is AED in first aid and how can you use the same in any emergency situation?

What is AED in First Aid?

In order to increase the chances of survival for individuals who have suffered from sudden cardiac arrest, AEDs have been used by medical professionals as well as first responders and in public places like airports, schools and workplaces. 

SCA happens when the heart stops beating suddenly and, if not treated immediately, can result in brain damage or death. That’s why AEDs are intended to administer an electric shock to the heart to help restore regular beating. Automated External Defibrillators (AEDs) are machines designed to deliver a shock to the heart in order to treat Sudden Cardiac Arrest (SCA). AEDs are portable and easy to use for anyone trained in cardiopulmonary resuscitation (CPR). 

These devices are a crucial component in the survival chain, helping restore the heart’s normal rhythm so oxygen can flow to the brain and other vital organs. 

Importance of AED in First Aid

Using an AED in first aid is crucial and can help save someone’s life who is experiencing sudden cardiac arrest. Below are some of the key reasons why an AED is useful in first aid:

Can restore a normal heart rhythm
Increases the chance of survival
Easy to use
Fast response time
Portable and readily available
Safe to use with built-in safety features
Anyone, regardless of their medical training or experience, can use


You can visit our other blog on 9 reasons why first aid is important for a more elaborate explanation.

How does an AED Work?

The heart has four hollow chambers:

  • two on the right take blood from the body and transmit it to the lungs for oxygen, 
  • and two on the left collect freshly oxygenated blood from the lungs and transport it throughout the body.

The heart’s upper right chamber contains specialised pacemaker cells that regulate the heart’s rate. When the coronary arteries surrounding the heart become damaged, either enough oxygen cannot reach the pacemaker cells or enough blood cannot reach the heart muscle, resulting in a heart attack or ventricular fibrillation.

The electrical shock from an AED can effectively reset the heart muscle, allowing it to reestablish its regular rhythm and begin pumping again.

Let’s get a detailed overview of the two main types of AED.

CPR training session using AED

Types of AED

The two main types of AED are:

  • Fully automatic AED
  • Semi-automatic AED

Fully Automatic AED

After connecting the electrode pads and turning on the device, this type of AED will analyse the person’s heart rhythm and, if a shock is required, will deliver it automatically after a prompt or countdown period without any input from the rescuer. A completely automatic AED has the advantage of requiring less user interaction, making it a desirable solution for persons with little or no training.

Semi-automatic AED

This AED needs the rescuer to initiate the shock by pressing a button. It will still evaluate the heart rhythm and determine if a shock is required, but the rescuer must follow the device’s directions to give the shock manually. The benefit of a semi-automatic AED is that the rescuer has more control over the device and can delay the shock if necessary.

Nurse conducting resuscitation using AED on a dummy

How to Use An AED?

If you are interested in learning how to use an AED in a medical emergency, you might wonder, “What is AED training in first aid?” It involves learning how to safely and effectively use an AED to help save a person experiencing sudden cardiac arrest. 

Even after training, remembering how to operate an AED correctly might be challenging. We’ve designed a brief step-by-step guide for you. To use an AED, follow these general guidelines:

AED Steps

The following AED protocols should be used if you are taking care of a non-breathing adult or child who is at least 55 pounds and eight years old.

Make sure the area is safeEnsure the area is safe for you and the individual in need before utilising the AED. Move the person safely away from water or other risks if necessary. Before applying the AED, remove any medicated adhesive patches from the victim, such as  

  • nicotine, 
  • birth control, 
  • nitroglycerin, 
  • or pain medication. 
Turn on the AEDPress the power button to turn the AED on.
Expose the person’s chestRemove all clothing and jewellery covering the chest and wipe the chest dry if it is wet.
Attach the electrode padsAvoid placing the pads directly over a pacemaker.

Following the illustrations or vocal directions on the AED pads, open the electrode pads’ packaging and attach them to the person’s bare chest:

  • Place one pad on the top right side of the chest, exactly below the collarbone.
  • Put the other pad on the lower left side of the chest, just below the left armpit.
Analyse the heart rhythmIf necessary, attach the pad connector cord to the AED. Prepare to have the AED examine the heart rhythm.

  • Ensure that no one is touching the person.
  • Say “CLEAR!” loudly and commandingly.
Deliver a shock if advisedIf the AED advises a shock,

  • ensure no one is touching the victim,
  • then press the shock button.

If the AED is fully automatic, the shock will be given automatically following a prompt or countdown.

Begin CPRPerform CPR with 30 chest compressions and two rescue breaths immediately after administering a shock. Until emergency medical services come, the AED will prompt you to start CPR.

Things to Remember

  • Do not use an AED on a child under the age of one year.
  • When using an AED on a child under the age of eight or weighing less than 55 pounds, apply paediatric pads and follow the AED’s instructions for administering a shock appropriate for the child’s age and weight. 
  • Some AEDs feature a paediatric mode that will adjust the shock level accordingly. If the victim is an infant, one should use a manual defibrillator. 

You may visit our other blog, What is the first aid treatment for heart attack?

Wrapping Up

Hopefully, our write-up on “What is AED in first aid” has thoroughly acquainted you with a medical device applied to treat sudden cardiac arrest in a first aid setting. While AEDs can be pretty helpful in treating sudden cardiac arrest, they are not suited for all forms of cardiac arrest.

For example, an AED may be ineffective if the person is having a heart attack or another non-cardiac incident. In these situations, it is vital to seek medical treatment as soon as possible and to follow proper first aid techniques.


What is the difference between a heart attack and cardiac arrest?

When one of the coronary arteries becomes clogged, it causes a heart attack. The heart muscle is then deprived of its vital blood flow and, if left untreated, begins to die due to a lack of oxygen. On the other hand, cardiac arrest occurs when a person’s heart ceases pumping blood around their body, and they cease breathing normally.

Are CPR and AED the same?

CPR and AED are not similar. People use CPR as a set of manual techniques to keep blood and oxygen circulating through the body. In contrast, an AED is a device that provides an electrical shock to the heart to restore its normal rhythm following a cardiac arrest.

What is an AED checklist?

An AED checklist is a set of items and procedures to ensure that an AED is in good working condition and ready for use in an emergency. Some common items to see on an AED checklist are the following:

  • Location
  • Inspection
  • Battery and electrode pad expiration dates
  • Indicator lights
  • Maintenance and testing.

Who is qualified to use an AED?

Non-medical professionals, such as firefighters, police officers, security guards, teachers, family members of high-risk individuals, and spectators, can use AEDs. In a sudden cardiac arrest, anyone can (and should) use an AED.

What is the AED 3 minute rule?

The AED 3-minute rule refers to the suggested timing for using an AED in a cardiac arrest situation. The rule mandates using an AED as soon as possible after a victim collapses to improve their survival rate.


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Ricky Kambray

Hey this is Ricky Kambray an award-winning first-aid trainer with over 20 years of healthcare and teaching expertise. Highly certified general nurse regularly appears in the press discussing accident prevention and first aid advice.