How an AED Is Used During Sudden Cardiac Arrest
For an unresponsive person who is not breathing normally, call emergency services, start CPR, turn on an AED, attach pads to the bare chest, keep everyone clear during analysis and shock, then resume CPR immediately.
Timeline
- At collapse: Check responsiveness and normal breathing, call 911 or direct a bystander to call, send for an AED and start CPR.
- When the AED arrives: Turn it on, expose and dry the chest, attach pads as pictured and follow every voice or screen prompt.
- After analysis or shock: Resume CPR immediately and continue following prompts until the person recovers or emergency professionals take over.
Sudden cardiac arrest means the heart unexpectedly stops pumping blood. A person typically collapses, is unresponsive and is not breathing normally; occasional gasps are not normal breathing. Call 911 immediately, put the phone on speaker if useful, send someone to retrieve an automated external defibrillator, and start CPR. Emergency dispatchers can coach the response, and early CPR plus defibrillation can improve survival. [1][2][3]
An AED is designed to analyze the heart rhythm and decide whether a shock is appropriate. It will not simply shock everyone to whom pads are attached. Turn on the unit—some start when the lid opens—and follow its spoken and visual prompts. Continue CPR while another rescuer prepares the device when possible, minimizing pauses in chest compressions. [1][2]
Expose the chest and wipe it dry. Remove the backing and place the pads exactly as their pictures show, commonly one on the upper right chest and one on the lower left side below the armpit. Plug in the pad cable if the device instructs. For a small child, use pediatric pads or mode when available and follow the device diagram; do not improvise placement from memory. [1][2][4]
When the AED says it is analyzing, stop CPR and make sure no one is touching the person. Say “clear” loudly and visually confirm separation. Movement can interfere with rhythm analysis. If the AED advises a shock, again clear everyone and press the flashing shock button when prompted, unless the model delivers the shock automatically. Never touch the person during shock delivery. [1][2]
Immediately resume CPR after a shock, or when the AED says no shock is advised. A no-shock message does not mean the emergency is over; the rhythm may still require CPR and advanced medical care. Continue the cycles directed by the device and dispatcher until the person shows clear signs of life, trained responders take over, the scene becomes unsafe or the rescuer cannot continue. [1][2][3]
Use the AED in place and follow its own prompts for unusual circumstances. Keep pads from touching each other, use the child configuration the manufacturer specifies, and do not delay lifesaving care merely to determine an exact age or weight. Water, medication patches, implanted devices, excessive chest hair and pregnancy can affect technique, so current CPR/AED training is the best preparation for safe adjustments. [1][2][4]
Public-access AEDs need maintenance before an emergency. The responsible organization should inspect readiness indicators, batteries, pads, recalls and expiration dates according to the manufacturer and local program rules. Training is strongly recommended even though the unit guides a rescuer. This overview supports, but does not replace, certified CPR/AED training, the device instructions or real-time directions from emergency dispatch and medical responders. [2][3][4]
Sources
- American Red Cross — AED Steps
- U.S. Food and Drug Administration — How AEDs in Public Places Can Restart Hearts
- U.S. Food and Drug Administration — Automated External Defibrillators
- U.S. Food and Drug Administration — Avive Automated External Defibrillator Approval