The most reassuring thing about AEDs

AEDs are designed for ordinary people, not just trained medics. They give clear voice prompts. They won’t deliver a shock unless the heart rhythm calls for one. They tell you exactly what to do at every step. You can’t electrocute someone with a normal heartbeat by accident — the device protects against that.

What that means in practice: if you’re standing next to someone in cardiac arrest and there’s an AED nearby, use it. Even with zero training, you’ll do better than not trying.

The 6 steps, in order

1. Confirm the casualty needs an AED

   Check responsiveness — shake the shoulders, shout “Are you okay?” Check for normal breathing — look at the chest for 5–10 seconds. If the person is unresponsive AND not breathing normally (or only gasping), this is cardiac arrest. Call 911 immediately (or have someone else call), then have someone retrieve the AED while you start CPR. Every second matters.

2. Turn on the AED

   Open the lid or press the power button. The device immediately starts voice prompts. From this point on, the AED tells you what to do — listen and follow.

3. Expose the chest

   Remove or cut away the casualty’s shirt. The pads need direct skin contact to work. Wipe the chest dry if it’s wet from sweat, rain, or water. Remove any visible medication patches (nicotine, nitroglycerin, hormone, etc.) — wipe the area clean. Excessive chest hair only matters if the pads won’t stick — most AEDs include a razor in the kit. For larger breasts, place the lower pad just below the breast, not over breast tissue.

4. Attach the pads

   The pads have pictures showing where they go. Standard placement: one pad on the upper right chest, just below the collarbone. The other pad on the lower left side, below the armpit, over the ribs. Press firmly to make sure they stick. The pads are pre-gelled and disposable — pull off the backing as you place them.

5. Let the AED analyze

   The AED will say “stand clear” or “analyzing — do not touch the patient.” Step back. Make sure nobody is touching the casualty. The device is reading the heart rhythm and deciding whether a shock will help. This takes about 10–15 seconds.

6. Deliver the shock if advised, then resume CPR

   If the AED says “shock advised,” make sure nobody is touching the casualty, then press the shock button (some AEDs deliver automatically without a button). Right after the shock — or if “no shock advised” — immediately resume CPR: 30 compressions, 2 rescue breaths, repeat. The AED will re-analyze every 2 minutes and tell you when to stop CPR for the next analysis. Keep going until paramedics arrive.

Using an AED on a child

The principles are the same, with a few specifics:

• Children under 8 or under ~25 kg — use pediatric pads if available. They deliver a lower-energy shock calibrated for smaller bodies.
• If pediatric pads aren’t available, adult pads can be used on a child in an emergency. Place them so they don’t overlap — front-back placement (one on chest, one on back) may be needed for smaller children.
• For infants under 1 year, manual CPR is generally prioritized; AED use is still considered if available with pediatric pads.
• Some AEDs have a child mode switch on the device itself that adjusts the energy delivery rather than requiring different pads.
• The Chase McEachern Act protects users using AEDs on children in good faith, just as it does for adults.

Special situations

Wet casualty or wet surface

Move the casualty to a dry area before applying the AED if at all possible. Wipe the chest dry. If you’re outdoors in rain, position yourself to minimize water on the casualty during shock delivery.

Metal surface

Move the casualty off the metal if possible. If not, the AED will still work — modern AEDs deliver the shock through the pads, not through the body’s contact with the ground. The risk of bystander shock through metal contact is minimal but the precaution is reasonable.

Pacemaker or ICD

You’ll see a small bump or scar under the skin (usually upper left chest). Place the AED pad at least an inch away from the device — don’t put the pad directly over it.

Pregnancy

Use the AED normally. The shock targets the heart, not the abdomen. Pregnant women in cardiac arrest need the same defibrillation as anyone else.

Hairy chest

If the pads won’t stick because of chest hair, most AED kits include a razor. Quick shave on the pad areas, then apply. Some AEDs include a “rip and replace” approach — apply the first set of pads to remove hair when you tear them off, then apply a fresh set.

Jewelry

Remove necklaces or move them out of the pad area. Don’t waste time on small items like piercings — just place the pads around them.

What if the AED says “no shock advised”?

This doesn’t mean stop helping. It means the heart rhythm at that moment isn’t a shockable rhythm. Some cardiac arrest rhythms (asystole, pulseless electrical activity) don’t respond to defibrillation — but high-quality CPR keeps blood flowing until either a shockable rhythm returns or paramedics arrive with additional interventions.

Resume CPR immediately: 30 compressions, 2 rescue breaths, repeat. The AED will re-analyze every 2 minutes. Keep going.

What if the AED makes a mistake?

It won’t. AEDs are designed so they only deliver a shock when the rhythm calls for one. If you accidentally place pads on someone with a normal heartbeat, the device will analyze the rhythm and say “no shock advised.” You physically cannot deliver a shock to someone who doesn’t need it. This is the safety feature that makes AEDs usable by bystanders.

How CPR and AED work together

The chain of survival in cardiac arrest:

1. Recognize the event (unresponsive, not breathing)
2. Call 911
3. Start CPR immediately
4. Use the AED as soon as one is available
5. Paramedics arrive with advanced care

CPR keeps blood flowing to the brain and heart while the AED is being retrieved and applied. The AED then tries to restart the heart’s normal rhythm. After the shock — or if no shock advised — CPR resumes immediately to keep blood flowing until the next analysis or until EMS takes over. Neither CPR nor AED alone is as effective as the combination.

Training matters

The Chase McEachern Act protects untrained bystanders, and the AED’s voice prompts make it possible to use one with no training. But trained users respond faster, place pads correctly the first time, and integrate AED use smoothly with high-quality CPR. Standard CPR Level C, Standard First Aid, and BLS courses all include AED training as part of the curriculum — you don’t need a separate AED-specific course.