Automated external defibrillators: Do you need an AED?

An AED may save your life during cardiac arrest. Weigh the pros and cons to see if you should get one.

By Mayo Clinic Staff

If you've ever watched a TV medical drama, chances are you've seen someone shocked back to life by a doctor who yells, "Clear" before delivering a jolt of electricity to the person's chest to get the heart beating again.

The machine being used is called a defibrillator, and its use isn't limited to a hospital setting. Devices called automated external defibrillators (AEDs) can be used at home and in schools and are also found in a number of public places. These lightweight, portable devices are available without a prescription.

If you have severe heart disease, you're at risk of sudden cardiac arrest and might want to consider having an AED. But AEDs can resuscitate you only if you have a specific type of heart rhythm problem. Talk to your doctor about whether owning an AEDs could help save your life.

When is an AED needed?

AEDs are used to revive someone from sudden cardiac arrest. This usually occurs when a disruption in the heart's electrical activity causes a dangerously fast heartbeat (ventricular tachycardia) or a fast and irregular heartbeat (ventricular fibrillation). If you're having one of these irregular heart rhythms, your heart doesn't pump effectively and may even stop.

When this happens, your brain and other vital organs don't get the blood and oxygen they need, and you can even die if you don't get treatment within minutes. The sooner your heart's normal rhythm is restored, the greater the chance that you won't have permanent damage to your brain and other organs.

If you're having ventricular fibrillation or ventricular tachycardia and an AED is nearby, a bystander in a public place or a family member can use it to jolt your heart back to a normal rhythm and possibly save your life.

Cardiopulmonary resuscitation (CPR) after cardiac arrest can keep blood flowing to your heart and brain for a time. But often only defibrillation can restore the heart's normal rhythm. Together these treatments can improve your chances of survival.

How to use an AED

If you see that someone has fainted and suspect that he or she may need an AED:

  • Check to see if the person is breathing and has a pulse.
  • If you cannot feel a pulse and the person is not breathing, call for emergency help. If there are other people present, one person should call 911 while the other prepares the AED. If you're alone, call 911 or emergency services first to make sure help is on the way.
  • Turn on the AED. The automated external defibrillator will give you step-by-step voice instructions explaining how to check for breathing and a pulse and how to position electrode pads on the person's chest.
  • Deliver the shock. When the pads are in place, the AED automatically measures the person's heart rhythm and determines if a shock is needed. If it is, the machine tells the user to stand back and push a button to deliver the shock. The AED is programmed not to deliver a shock if a shock isn't needed.
  • Administer CPR. Start CPR after the shock is delivered if CPR is still needed. The AED will also guide users through CPR. The process can be repeated as needed until emergency crews take over.

The home AED comes with an instructional training video that shows how to use and maintain the device. If you buy an AED, everyone in your home should watch the video and review it periodically.

Having an AED nearby when you need it

Police and ambulance crews carry AEDs, and they're commonly available in many public places, including malls, office buildings, sports arenas, gyms and airplanes. However, many cardiac arrests occur at home, so having a home AED can save precious minutes in reviving a person with ventricular fibrillation and ventricular tachycardia.

Proponents of home AEDs say putting them where they're needed most will save many lives. But critics argue there's no reliable evidence that home defibrillators save more lives.

Deciding if an AED is right for your home

For some people who have a high risk of cardiac arrest, having an AED can provide peace of mind and might help save their lives. Here are some things to keep in mind as you consider whether to buy an automated external defibrillator:

  • Your risk of sudden cardiac death. If you're at high risk of sudden cardiac death due to a specific heart rhythm problem, your doctor will likely recommend an implantable cardioverter-defibrillator (ICD) rather than an AED. An ICD is implanted in your chest and connected to your heart via a wire that can deliver a shock when needed.
  • Your living arrangements. You need someone with you to use the AED if you have cardiac arrest. And the person needs to be agile enough to get on the floor to use the device and get back up. If you live alone or if the person you live with can't get up and down, a home AED might not make sense.
  • Your costs. Home AEDs can be expensive and aren't usually covered by insurance.
  • Your overall health and philosophy. If you have numerous medical problems, a terminal illness or a very weak heart that hasn't responded to treatment, you might choose not to be resuscitated from sudden cardiac death.

Tips for proper use and maintenance of AEDs

If you get an AED for your home, make sure that family, friends and visitors know where it is and how to use it. And you need to maintain it properly. Here are some tips for buying and maintaining your home AED:

  • Buy an AED approved by the U.S. Food and Drug Administration. You can check the FDA's website for a list of approved devices.
  • Register your AED with the manufacturer. That way you'll receive safety alerts and recall notices. Also, check the manufacturer's website periodically to keep current on information about your device.
  • Learn what you need to know. Consider enrolling yourself and whoever might need to use your home AED in a community education class, such as classes offered by the American Red Cross, to learn how to use your automated external defibrillator properly and to perform CPR. This will also enable you to come to the rescue if someone has cardiac arrest in a public place and there's an AED nearby.
  • Have a practice run using the AED as you would in an actual emergency. Because the AED works only on certain types of cardiac arrest, the people who might need to use the device should know what steps to take if the AED indicates that a shock isn't needed but the person remains unresponsive.
  • Store your AED in an easily accessible place. Make sure family, friends and visitors know where it is.
  • Keep the AED maintained properly, including installation of new batteries as needed, typically every four years, and replacement of electrode pads as needed. Follow the manufacturer's instructions and be sure to have spare pads on hand.
  • Heed alarms. Home AEDs are designed to test themselves to make sure they're working properly. Be sure you can hear the alarm. If your machine starts beeping or you see a light flashing, call the device manufacturer. Keep the number handy.
  • Buy the right AED for you. Some AEDs aren't intended for home use, but rather for emergency crews or for installation in public places. Don't be lured by websites or other sellers offering AEDs not intended for home use.

AEDs offer a way to save a life. Before buying one, talk to your doctor and do research. And don't forget to learn the basics, such as CPR.

April 16, 2020 See more In-depth

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