How to use an AED in 7 steps
Quick answer: Call 911, start CPR, turn on the AED and follow its voice prompts. Put the pads on the bare chest, stand clear while it analyzes, press the shock button if it tells you to, then go right back to CPR until help takes over.
You can’t hurt someone in cardiac arrest by using an AED. It checks the heart rhythm and only allows a shock when one is needed. Every minute without CPR and defibrillation lowers the chance of survival, so act fast.
Step 1: Make sure the scene is safe
Check for traffic, electrical hazards, standing water or other dangers before you approach.
Step 2: Check the person and call 911
Tap their shoulder and shout, “Are you OK?” If they don’t respond and aren’t breathing normally (or are only gasping), call 911 or have someone call, and send someone to get the AED.
Step 3: Start CPR right away
Don’t wait for the AED. Push hard and fast in the center of the chest, at least 2 inches deep for an adult, at 100 to 120 compressions per minute, and let the chest fully rise between compressions.
Step 4: Turn on the AED
As soon as the AED arrives, turn it on and follow the voice prompts. On a Philips HeartStart OnSite, pull the green handle. On a Philips HeartStart FRx, press the green On/Off button.
Step 5: Attach the pads
Expose the chest. Wipe it dry if it’s wet, quickly shave thick chest hair if the pads won’t stick, and remove any medication patches. Place the pads as shown in the pictures on them:
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One pad on the upper right chest, just below the collarbone
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One pad on the lower left side, a few inches below the armpit
If you see a bump under the skin from a pacemaker or implanted defibrillator, place the pad about an inch to the side of it, not directly over it.
Step 6: Stand clear and shock if advised
The AED analyzes the heart rhythm on its own. Make sure no one is touching the person and say “Clear!” If a shock is advised, press the flashing shock button when prompted. If no shock is advised, continue CPR.
Step 7: Resume CPR and keep following the prompts
Restart chest compressions immediately after the shock. Leave the pads on and the AED turned on; it will reanalyze about every 2 minutes. Keep going until EMS takes over or the person starts breathing normally.
Using an AED on a child or infant
For children under 8 years old or under 55 pounds, use infant/child pads if you have them (Philips OnSite) or insert the Infant/Child Key (Philips FRx). If pediatric pads aren’t available, use adult pads and don’t delay. On a small child, place one pad on the center of the chest and one on the back so the pads don’t touch.
Common questions
Can I get in trouble for using an AED?
Pennsylvania’s Good Samaritan law protects people who use an AED in good faith during an emergency from civil liability, except for gross negligence or intentional harm. The law says using an AED should not be delayed while waiting for EMS. (General information, not legal advice.)
Can an AED shock someone who doesn’t need it?
No. An AED analyzes the heart rhythm and only advises a shock for a rhythm that needs one.
What if the person is wet?
Move them out of standing water if you can, and wipe the chest dry before attaching the pads.
Do we still need CPR if we have an AED?
Yes. CPR keeps oxygen moving to the brain; the AED works to restore the heart’s rhythm. They work together.
Practice before you need it
Reading the steps helps. Hands-on practice builds the confidence to act. CMR CPR brings AHA and ECSI CPR/AED certification to your workplace, school or church for groups of 10 or more. Contact us to schedule training, or shop new and refurbished AEDs for your space.
More from the AED Center: How much does an AED cost? · How often do you need to replace an AED?
This guide is for general education and does not replace certified CPR/AED training.
