Defibrillators When to use an AED in an Emergency


A person whose heart stops from cardiac arrest must get help within 10 minutes to survive.

Fainting is usually the first sign of cardiac arrest. If you think someone may be in cardiac arrest, try the following steps:

  • If you see a person faint or if you find a person already unconscious, first confirm that the person cannot respond. The person may not move, or his or her movements may look like a seizure.
  • You can shout at or gently shake the person to make sure he or she is not sleeping, but never shake an infant or young child. Instead, you can gently pinch the child to try to wake him or her up.
  • Check the person’s breathing and pulse. If the person is not breathing and has no pulse or has an irregular heartbeat, prepare to use the AED as soon as possible.

    Where to find an AED

    You often find AEDs in places where large numbers of people gather, such as shopping malls, golf courses, gyms and swimming pools, businesses, airports, hotels, sports venues, and schools. You can also purchase a home-use AED.

    The AED is in a case about the size of a large first-aid kit. Many AEDs have a heart logo in red or green. Large letters on the case or the wall where it is stored might spell out A–E–D.

    How to use an AED

    Even someone without special training can respond in an emergency by following the instructions relayed by the device. The information below can help you use an AED correctly.

    • Call 9-1-1 or have someone else call 9-1-1. If two rescuers are present, one can provide CPR while the other calls 9-1-1 and gets the AED.
    • Make sure the area around the person is clear. Touching the person could interfere with the AED’s reading of the person’s heart.
    • Listen for voice prompts that tell you when and how to give an electric pulse or shock if one is needed to restore a normal rhythm. Electrodes deliver the shock, and some deliver more than one shock with increasing.
    • Start CPR again after delivering the shock, if the device instructs you to do so.
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