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 health care provider 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.

People with severe heart disease who are at risk of sudden cardiac arrest might consider having an AED. But AEDs can resuscitate people only with a specific type of irregular heart rhythm. Talk to a health care provider about whether owning an AED 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). Either of these irregular heart rhythms keeps the heart from pumping effectively and can cause it to stop.

When this happens, the brain and other vital organs don't get the blood and oxygen they need. This requires treatment within minutes to prevent death. The sooner the heart's rhythm is restored, the greater the chance there won't be permanent damage to the brain and other organs.

If an AED is near someone having ventricular fibrillation or ventricular tachycardia, a bystander in a public place or a family member can use it to jolt the heart back to a regular rhythm. Using the AED could possibly save a life.

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

How to use an AED

If someone has fainted and might 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 can 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 gives you step-by-step voice instructions. It will tell you how to check for breathing and a pulse and how to position electrode pads on the person's bare 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.
  • Start CPR. Begin 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 instructions that tell how to use and maintain the device. In homes with an AED, it's helpful for everyone in the home to read the instructions and review them periodically.

Having an AED nearby when needed

Police and ambulance crews carry AEDs. Plus, 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 or 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 the home

For some people at 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 when considering whether to buy an automated external defibrillator:

  • Risk of sudden cardiac death. For someone at high risk of sudden cardiac death due to a specific heart rhythm problem, a health care provider will likely recommend an implantable cardioverter-defibrillator (ICD) rather than an AED. An ICD is implanted in the chest and connected to the heart through a wire that can deliver a shock when needed.
  • Living arrangements. You need someone with you to use the AED if you have cardiac arrest. And the person needs to be able 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.
  • Costs. Home AEDs can be expensive and aren't usually covered by insurance.
  • Overall health and quality of life. Someone with many medical conditions, especially those that might be fatal, or who has a very weak heart that hasn't responded to treatment 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 keep it working properly. Here are some tips for buying and maintaining a home AED:

  • Buy an AED approved by the Food and Drug Administration (FDA). The FDA's website lists approved devices.
  • Register the AED with the manufacturer. That way you'll receive safety alerts and recall notices. Also, check the manufacturer's website from time to time to keep current on information about your device.
  • Learn what you need to know. Consider enrolling yourself and others who might need to use your home AED in a community education class. The American Red Cross, for example, teaches how to use an automated external defibrillator properly and to perform CPR.
  • Have a practice run using the AED. Because the AED works only on certain types of cardiac arrest, it's helpful for the people who might need to use the device to know what steps to take if the AED indicates that a shock isn't needed but the person remains unresponsive.
  • Store your AED in a place that's easy to get to. Make sure family, friends and visitors know where it is.
  • Keep the AED working properly. Install new batteries as needed, typically every four years. Replace electrode pads as needed. Have spare pads on hand. Follow the manufacturer's instructions.
  • 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 use by emergency crews or 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 a health care provider and do research. And don't forget to learn the basics, such as CPR.

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April 26, 2022 See more In-depth

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