7.4 – How to Use the Automated External Defibrillator (AED)

If an AED is immediately available, refer to the instructions enclosed with the AED, or that automatically begin when the AED is engaged.

Note: This content is courtesy of the National Institutes of Health. Click here to access the website.

  1. Confirm that the person is unconscious and cannot respond by shaking the person and loudly asking if they are ok.
    Note: Do not shake children or infants; instead, pinch them to try to wake them.
  2. Call 911. If a second person is present, one should start performing CPR while the other calls for emergency aid and retrieves the AED.

If breathing and pulse are absent or irregular, prepare to use the AED as soon as possible.

  1. Turn on the AED’s power. The device will give you step-by-step instructions. You’ll hear voice prompts and see prompts on a screen.
  2. Expose the person’s chest. If the person’s chest is wet, dry it. AEDs have sticky pads with sensors called electrodes. Apply the pads to the person’s chest as pictured on the AED’s instructions.
  3. Place one pad on the person’s right center of the chest above the nipple. Place the other pad slightly below the other nipple and to the patient’s left of the ribcage.


  • Make sure the sticky pads have good connection with the skin. If the connection isn’t good, the machine may repeat the phrase “check electrodes.”
  • If the person has a lot of chest hair, you may have to trim it. (AEDs usually come with a kit that includes scissors and/or a razor.)
  • If the person is wearing a medication patch that’s in the way, remove it and clean the medicine from the skin before applying the sticky pads.
  • Keep the defibrillator pads at least one inch away from piercings or implanted devices, such as a pacemaker.
  1. Remove metal necklaces and underwire bras. The metal may conduct electricity and cause burns. You can cut the center of the bra and pull it away from the skin.
  2. Check that the wires from the electrodes are connected to the AED. Make sure no one is touching the person, and then press the AED’s “analyze” button. Stay clear while the machine checks the person’s heart rhythm.
  3. If a shock is needed, the AED will let you know when to deliver it. Stand clear of the person and make sure others are clear before you push the AED’s “shock” button.
  4. Start or resume CPR until emergency medical help arrives or until the person begins to move. Stay with the person until medical help arrives, and report all of the information you know about what has happened.
  5. After you use the AED, give CPR until emergency medical help arrives or until the person begins to move. Try to limit pauses in CPR.
  6. After 2 minutes of CPR, you can use the AED again to check the person’s heart rhythm and give another shock, if needed. If a shock isn’t needed, continue CPR.