By Jointra Editorial Team, Certified EMT
When the heart goes into ventricular fibrillation (VF) — the chaotic, disorganized rhythm that causes most sudden cardiac arrests — the only treatment is defibrillation: delivering an electrical shock to reset the heart's rhythm. Every minute without defibrillation decreases survival by 7–10%. CPR buys time, but defibrillation is the cure.
AEDs are designed to be used by untrained bystanders. They are found in airports, schools, gyms, shopping centers, and many other public places. Finding and using one while calling 911 and performing CPR is the chain of survival.
Step 1: Turn it on Open the case and press the power button (or lift the lid on some models — it powers on automatically). Follow the voice and visual prompts.
Step 2: Attach the pads Place the pads as shown in the diagrams on the pads themselves:
Bare skin only — remove clothing, dry wet skin, wipe away excessive chest hair if possible (a razor is often included in AED kits).
Step 3: Let the AED analyze Stop CPR and make sure no one is touching the patient. The AED will analyze the heart rhythm. Do not touch the patient during analysis.
Step 4: Deliver the shock (if advised) If a shock is indicated, the AED will charge and tell you to press the shock button. Shout "Clear!" and confirm no one is touching the patient before pressing.
Step 5: Resume CPR Immediately after the shock, resume CPR — 30 compressions to 2 breaths. Continue until EMS arrives or the patient regains consciousness.
The AED will re-analyze every 2 minutes. Follow its prompts.
Children under 8 or under 55 lbs: Use pediatric pads if available. If only adult pads are available, place one on the chest and one on the back.
Pacemaker or ICD: Place pads at least 1 inch away from visible device bumps.
Water: Move the patient to a dry surface before use.
Medication patch (nitroglycerin, nicotine): Remove patch and wipe skin before placing pad.
If the AED says "no shock advised," it means the heart rhythm does not benefit from a shock — continue CPR. AEDs will never shock a patient who doesn't need it.