How to Use an AED: A Step-by-Step Guide

An automated external defibrillator (AED) is engineered so that anyone — trained or not — can use it in a cardiac emergency. The device talks you through every step and will only deliver a shock when one is truly needed. Combined with CPR, early defibrillation can double or triple a person’s chance of surviving sudden cardiac arrest. Here is how to use an AED, step by step.

If you witness a collapse: check responsiveness, call 911 (or have someone else call), and send someone for the nearest AED while you begin CPR.

Step 1: Turn the AED on

Open the case and press the power button (some models turn on automatically when opened). From here, the device’s voice prompts will guide you — just follow them.

Step 2: Prepare the chest

Expose the person’s bare chest. Make sure the skin is dry; wipe away sweat or water. Remove any medication patches and, if the chest is very hairy where the pads go, use the razor in the AED kit so the pads stick well.

Step 3: Attach the pads

Peel the electrode pads and place them on bare skin exactly as shown in the diagram on each pad — typically one on the upper right chest and one on the lower left side. Press firmly so they adhere fully.

Step 4: Let the AED analyze

Stop CPR and make sure no one is touching the person. The AED will analyze the heart rhythm and tell you whether a shock is advised. Stay clear during analysis.

Step 5: Deliver the shock if advised

If a shock is advised, confirm everyone is clear of the person, then press the flashing shock button. A fully automatic AED will deliver the shock itself after a warning — just stay clear.

Step 6: Resume CPR and follow the prompts

Immediately resume chest compressions and continue following the AED’s prompts. It will re-analyze every couple of minutes. Keep going until EMS takes over or the person shows clear signs of life.

Using an AED on a child

For children under about 8 years old or 55 pounds, use pediatric pads or a pediatric setting/key if your device has one, which lowers the energy delivered. If pediatric pads are not available, use adult pads rather than delaying care — just keep the pads from touching each other. Keep a current set of pediatric pads on hand wherever children may be present.

A few safety reminders

• Never touch the person during analysis or shock delivery.
• Move the person off metal surfaces and out of standing water before shocking.
• Keep the device’s pads and battery in date so it is ready when seconds count.

AEDs are designed for untrained use, but hands-on CPR/AED training builds the confidence to act fast. Practicing on an AED trainer is a smart investment for any workplace or facility.

Frequently asked questions

Do you need training to use an AED?

No. AEDs are designed for untrained bystanders and provide step-by-step voice prompts. Training is recommended because it builds speed and confidence, but it is not required to operate one.

Can you use an AED on a child?

Yes. Use pediatric pads or a pediatric setting for children under about 8 years old or 55 pounds. If pediatric pads are unavailable, use adult pads rather than delay care.

Will an AED shock someone who does not need it?

No. The AED analyzes the heart rhythm and will only enable a shock when it detects a shockable rhythm.

This guide is informational and is not a substitute for certified CPR/AED training or professional medical advice. In an emergency, always call 911 first.