What is a Defibrillator? How AEDs Work and How to Use Them

AED defibrillators are well-known tools, often seen in dramatic moments on screen and essential in emergency medical care.

An AED, or Automated External Defibrillator, is a portable device designed to treat sudden cardiac arrest by delivering an electric shock to the heart. While they are a staple for paramedics and widely used in hospitals across Australia, AED defibrillators are also designed for use by anyone, even without first aid training. However, there’s more to these life-saving devices than you might realise.

Understanding the different types of defibrillators and their specific functions is crucial. In this article, we’ll explore what a defibrillator is, when it should be used, and how it works. 

What is an AED Defibrillator?

An AED (automated external defibrillator) is a device that sends an electrical shock or pulse to the heart in order to restore a normal rhythm. These are commonly found in public places, stored in conspicuous locations where anyone can access them in case of an emergency. AEDs are used to both prevent and correct abnormal heart rhythms (arrhythmia). A defibrillator can restart a heart if it stops due to sudden cardiac arrest (SCA) or other heart conditions.

While every type of defibrillator works in essentially the same way, they each fulfil different roles for patients, healthcare professionals, and the general public. Below, we look at the different types of defibrillators and the normal activities that they are responsible for performing. 

What Are The Different Types of Defibrillators?

Manual External Defibrillator 

MEDs are the most recognisable defibrillators, thanks to TV. However, they can only be used by healthcare professionals and are primarily found in hospitals and ambulances. They are used in conjunction with an electrocardiogram (ECG), and the user needs to manually identify whether the patient requires a shock, and then what kind of voltage is required. 

These kinds of machines are expensive and are used in professional medical settings. They cost anywhere from $20,000 to $40,000. If you’re shopping for your hospital or medical facility, we recommend the Zoll X Series Defibrillator CCT, which is a lightweight and customizable option that professionals prefer.

Automated External Defibrillator 

AEDs use two paddles or electrode pads to deliver an electric shock to restore the natural heart rate in a similar way to MEDs. They were designed to allow anyone to use them in an emergency, and the automated computer analyses the heart rhythm to ascertain whether a shock is required—requiring little to no user input in order to save a patient’s life.

AEDs are readily available in many public areas, and some people even have portable ones in their homes. If you or a loved one is at high risk for needing defibrillation due to a heart condition, it may be worth owning a portable AED of your own. You can expect to pay anywhere from $1,000 to $4,000 for an AED for home use. For an affordable option, the Philips HeartStart Onsite AED is a great choice for people who would like extra peace of mind at home.

Implantable Cardioverter Defibrillator

ICDs are surgically placed within the chest cavity to check and correct arrhythmia. They work in a similar way to pacemakers; however, while pacemakers only deliver low-level shocks, ICD defibrillators are capable of delivering both low- and high-energy shocks. Since these devices require surgery, the cost can vary based on your medical coverage.

Wearable Cardioverter Defibrillators 

Like an ICD, a WCD can deliver both low- and high-energy shocks to the patient. In fact, the only difference is that these devices are attached to the skin with trailing wires connected to a unit that monitors your heart. WCDs are generally used temporarily while patients are waiting for ICDs or other cardiac procedures. Like ICDs, costs will vary greatly since these are obtained through your physician.

 

How Does an AED Defibrillator Work?

AED defibrillators work by identifying arrhythmia and heart failure using a sophisticated computer and then delivering a shock to return the heart back to its natural rhythm. As suggested by the name, defibrillators stop fibrillation, the “trembling” that someone’s heart muscles may experience during cardiac arrest.

AEDs achieve this by passing an electric current through the heart, shocking it back into rhythm. The defibrillator pads on an AED form a circuit, allowing electricity to pass through the body without harming it and, when placed correctly, focusing that current directly on the heart.

 

Safety Precautions and Best Practices for AED Usage

When using an automated external defibrillator, following best practices is important to ensure effective and safe assistance during cardiac emergencies. In this section, we outline essential safety precautions and best practices that should be followed when utilising an AED. By sticking to these guidelines, rescuers can increase the victims’ chances of survival while minimising risks and hazards. 

Call for help first

Always call emergency medical services before using the AED. AEDs are crucial, but professional medical help should be on the way as well. If you are busy providing emergency healthcare, ask a bystander to call 000.
Check for water or wet surfaces — Ensure the area around the person is dry before using the AED to avoid electrical hazards and electric shocks. 

Remove metal objects

Take off any metal objects like jewellery or piercings from the person's chest before applying the AED defibrillator electrodes. 

Check for paediatric settings

Some AEDs have paediatric settings, which reduce the energy delivered for use on children. Ensure you are using the appropriate setting for the person's age and weight, if available.

Clear communication

In a group setting, designate one person to be in charge and clearly communicate the steps and prompts provided by the AED. Another can be in charge of the first aid kit, and someone else should be calling emergency services. Assigning clear roles to everyone decreases the chances of something important being missed.

Avoid touching the person during analysis

When the AED is analysing the rhythm or delivering a shock, make sure no one is touching the person to prevent interference. 

Be cautious with implanted devices

If the person has an implanted pacemaker or defibrillator, place the AED electrodes at least one inch away from the device if possible.

Training is valuable

Proper CPR training and AED usage increases confidence and effectiveness in responding to emergencies. In addition, learning the difference between CPR vs AED is important.

 

Step-By-Step Guide: How to Use an AED Defibrillator

An AED consists of an analysis unit, or computer, and electrodes that are placed on the body, which, when combined, measure electrical signals from the heart. To help untrained individuals use AEDs correctly, there will be a diagram and set of instructions on the unit itself, telling you how to turn on the machine and begin the process. All clothing should be removed from the patient’s chest, arms, and abdomen before using the AED, and the pads should always be attached directly to the skin.

Once the pads are stuck to the body, the AED will begin to analyse the patient's heart rhythm. If the process does not start automatically, then ensure you push the analyse button indicated on the machine. During this process, you should not touch or move the patient.

If the AED determines that a shock is required, you will be instructed to press the button on the unit. Newer units will only shock once. Older units may shock up to three times, so be certain to read the instructions on the unit itself. More information on how to use an AED defibrillator can be found here.

Knowing how to use an AED properly can mean the difference between life and death during sudden cardiac arrest. Below, we provide a step-by-step guide to using an AED defibrillator, and by following these instructions, even individuals with minimal medical training can confidently and effectively respond to emergencies, delivering life-saving aid until professional medical assistance arrives. Don’t forget to review the terms and instructions on the AED, as well.

1. Turn on the AED and follow the voice prompts or visual instructions. 
2. Expose the person's chest by removing any clothing or accessories that might interfere with electrode placement.
3. Apply the AED electrodes to the person's bare chest as shown in the pictorial instructions. 
4. Stop CPR temporarily. Ensure that no one is touching the person during the AED's heart rhythm analysis.
5. If the AED advises a shock, have everyone stand clear and refrain from touching the person, then press the shock button as instructed to restore normal rhythm.
6. Resume CPR immediately after the shock, if advised by the AED, until EMS arrives. 
7. Once the person has been revived, stay close and keep an eye on them to ensure they remain conscious. Do not remove the AED pads from the person’s body, and do not turn off the AED. Once first responders arrive, you can let the professionals take over.

 

 

 

Where to Find an AED

AEDs have revolutionised the healthcare sector, allowing untrained bystanders to provide lifesaving treatment to anyone who requires it. Today, you will find them located within large public places including:

• Hospitals and other national institutes of health
• Schools
• Community centres
• Workplaces
• Business centres
• Sport centres
• Gyms
• Shopping centres
• Public libraries
• Zoos

 

Read more in my article How to Find Your Nearest AED in Australia. 

When to Use A Defibrillator

AED defibrillators should be used when a patient is unresponsive and AFTER their airway has been cleared and cardiopulmonary resuscitation (CPR) has been performed. This may be any condition where there is no pulse or response from the patient. However, it is also important to shake or otherwise try to wake up someone who is unresponsive before performing CPR or using an AED defibrillator. 

When to Use an AED

 

When Not to Use an AED

 

It’s crucial to follow the health information and guidance printed on the equipment, and to be cautious or avoid using an AED in the following circumstances:

• Heart Attack: Although the symptoms may resemble those of cardiac arrest, an AED will not help someone suffering from a heart attack.

• Water: If the patient is in water or is wet, it is important to remove them from the water and dry them off before using an AED.

• Medication Patch or Pacemaker: If the patient has a medication patch, remove it before using the AED. If the patient has a pacemaker, avoid placing the electrode pads directly over it.

• Faulty AED: Do not use the AED if it has an expired sticker, or if any part of the device appears damaged.

• Hairy Chest: If the victim has a hairy chest, the electrode pads may not adhere properly to the skin, which can prevent the AED from delivering an effective shock. In this case, it may be necessary to quickly remove the chest hair to ensure proper pad contact.

Always ensure the AED is used correctly and under appropriate conditions to maximize its effectiveness and the safety of the patient.

AED Defibrillator FAQs

What are the survival rates for people with heart conditions that require AED application?

Some estimates suggest that the use of AEDs in out-of-hospital cardiac arrest situations doubles the chances of survival for individuals.

Can AED defibrillators damage your heart?

It is highly unlikely that an AED will damage a patient’s heart, as the automated computer, step-by-step visuals, and voice prompts essentially make the process “foolproof.” Even if a patient does not require ventricular fibrillation, an AED will know this and not deliver unneeded shocks or electrical impulses.

Can an AED Harm or Shock Someone Not in Cardiac Arrest?

The good news is that modern AEDs are designed to be used by anyone, which means they take out the guesswork of using the device. The machine will not advise or issue a shock to a person who does not need it.

Do I Need to Perform CPR if I Have a Defibrillator?

AEDs should always be used in conjunction with CPR techniques. The role of the AED is to shock the heart back into a normal rhythm while chest compressions keep blood pumping throughout the body. You should continue CPR until the person regains consciousness and is breathing on their own.

Can AED Defibrillators Kill You?

Again, it is highly unlikely that and AED defibrillator will harm or kill a patient. They are designed to only work when required, delivering the required treatment as ascertained by the computer after analysing the person’s heart rhythm.

Can Anyone Use AED Defibrillators?

Anyone can use AED defibrillators, even without specific AED training, and they are designed exactly for this purpose. Instructions are included on the units themselves, and there are visual and audio prompts to make their usage even easier.

How Many Volts are in an AED Defib?

AEDs deliver anywhere from around 200-1000 volts, with the patient’s heart receiving around 300 joules of electrical energy.

How Much do AED Defibs Cost?

If you are looking to purchase an AED defibrillator for any purpose, you can expect to pay anywhere from $1000 AUD to $4000 AUD for a top brand. Additionally, a range of accessories and replacement parts may be included in your purchase to help your equipment last longer and continue to function for many years.

Where to Buy an AED Defibrillator?

AED defibrillators are available to buy from recognised medical equipment supply stores in Australia, and Medshop has a broad range of options from which to choose. Whether for your home, your business, or any other public place, we stock everything you need to ensure you have the very best lifesaving equipment to hand.

Explore the range or contact us to discuss your requirements or if you would like more information on any specific products. Additionally, for more information on other health topics and equipment, check back to the Medshop blog.