CPR, AED, and First Aid Training
AED 101 and How an AED Works
An automated external defibrillator (AED) is a portable device used during suspected cardiac arrest. It analyzes the heart’s electrical rhythm and delivers or advises an electric shock only when the rhythm calls for one. Voice and visual prompts guide the responder through the process.
An AED is used alongside CPR, not instead of it. Calling 911, starting CPR and using an AED as soon as it is available are important parts of the emergency response.
Find CPR and AED Training
When should an AED be used?
Use an AED for a person who collapses and is unresponsive and is not breathing normally. First make sure the scene is safe, call 911 and begin CPR. Ask another person to retrieve an AED when possible. Follow the dispatcher’s instructions and the device prompts.
An AED is not intended for a responsive person who is breathing normally. A suspected heart attack still requires emergency help, but an AED is used if the person develops signs of cardiac arrest.
How does an AED work?
Adhesive electrode pads connect the person to the AED. The device uses these pads to assess the heart rhythm. If it identifies a shockable rhythm, it prepares a shock and tells responders to stand clear. If a shock is not indicated, it advises the responder to continue care, including CPR as prompted.
A semi-automatic AED prompts a responder to press a shock button. A fully automatic AED delivers the shock after its warning sequence. With either type, no one should touch the person during rhythm analysis or shock delivery.
Why CPR is still needed
Chest compressions help circulate blood while the AED is retrieved and between its analysis cycles. A shock does not guarantee that normal circulation has returned. Resume CPR when the AED instructs you to do so, including after a “no shock advised” message.
Learn CPR basics
How To Use An AED
For an unresponsive person who is not breathing normally, call 911 and begin CPR. As soon as an AED becomes available, follow its prompts. The general sequence is:
Step 1
Turn on the AED.
Step 2
Expose the chest and dry it if wet. Apply the pads to bare skin using the diagrams on the pads and the device instructions.
Step 3
Connect the pad cable if the device requires it. If another responder is present, they can continue CPR while the pads are being prepared, until the AED directs everyone to stand clear.
Step 4
Keep everyone clear during rhythm analysis. Do not touch the person.
Step 5
If a shock is advised, make sure no one is touching the person. Press the shock button only when prompted, or allow a fully automatic device to deliver the shock after its warning.
Step 6
Resume CPR immediately when instructed, whether or not a shock was delivered. Follow further prompts until emergency responders take over, the person shows clear signs of life and normal breathing, the scene becomes unsafe, or you are physically unable to continue.
Using an AED on a child or infant
AEDs can be used for children and infants in cardiac arrest. Use the device’s pediatric pads or pediatric mode when available and appropriate, following its age or weight guidance. If pediatric pads are not available, adult pads may be used; the pads must not touch.
Pad position can differ for a small child or infant. Follow the pad diagrams, device instructions and dispatcher guidance. Training in pediatric CPR and AED use helps you practice these differences without delaying a response.
Keeping an AED ready for an emergency
An AED needs to be accessible and maintained. Follow the manufacturer’s inspection and storage instructions, check the readiness indicator, and replace pads and batteries as required. Assign someone to record checks and arrange replacement supplies after use.
Place the AED where responders can reach it quickly and make its location clear. Include it in the emergency response plan so people know who will call 911, retrieve the device, begin CPR and meet emergency responders.
Explore AED Equipment
What CPR and AED training covers
CPR and AED training gives you practice recognizing cardiac arrest, activating emergency help, performing compressions and following AED prompts. Practice also helps responders coordinate tasks and avoid touching the person during analysis or shock delivery.
HSI offers courses that combine CPR, AED and first aid skills. Choose the appropriate age groups and confirm any employer or licensing requirements. Available formats for eligible courses include classroom training, blended learning and Remote Skills Verification.
Explore HSI First Aid and CPR AED Training
AED frequently asked questions
No. The device analyzes the heart rhythm and delivers or advises a shock only when indicated. A “no shock advised” message does not mean you should stop care. Follow the AED instructions and resume CPR when prompted.
AED prompts are designed to guide responders, including people without prior training. Do not delay an emergency response to find a certification card. Training is still valuable because it provides practice using an AED with CPR.
No. An AED trainer simulates prompts for practice and does not deliver a therapeutic shock. An AED trainer cannot be used as a working AED, and a working AED must never be used in training. Keep all training equipment clearly identified.
Move the person out of standing water when it is safe and necessary, and dry the chest before applying pads. Follow the device instructions. Good pad contact and keeping everyone clear during analysis and shock delivery are important.
Consider who may need it, its intended location, pediatric capability, maintenance needs and the manufacturer’s instructions. Plan for training, inspections and replacement supplies as well as the initial purchase. HSI can help you determine the right AED for your workplace. Reach out to us at aed@hsi.com.
Find CPR and AED training with HSI
Practice the skills that connect CPR and AED use in an emergency. Explore HSI training for yourself or your team, and choose a course that fits your responsibilities.
This guide is for general education and does not replace practical training. In an emergency, call 911 and follow the emergency dispatcher’s instructions.
