When and When Not To Use an AED

Just as it’s important to know when to use AED units, it’s important to know when NOT to use automated external defibrillators (AEDs) as well. Learning the signs of sudden cardiac arrest (SCA) emergencies and the steps in what to do if someone needs CPR and AED use can save a person’s life during a cardiac emergency when every second counts.

When is an AED needed?

Sudden cardiac arrest can occur when a person’s heart suddenly stops beating effectively, stopping the blood flow to vital organs. An AED (automated external defibrillator) is used to revive someone’s heart back to a normal rhythm after experiencing sudden cardiac arrest and can dramatically increase a person’s chances of living.

AEDs are particularly effective for cases of ventricular fibrillation or ventricular tachycardia, which is another way to describe abnormal heart rhythms that can be life-threatening. Providing prompt emergency cardiac care can help restore the abnormal heart’s rhythm to a normal heart rhythm, once again.


When Should you NOT Use an AED?

While defibrillators are generally safe and easy to use, there are some situations in which their use is not recommended. The following guidelines will explain when you should not use an AED during an emergency.

Do not use an AED if the victim has/is:

  1. Conscious and responsive
  2. Normal breathing or a pulse
  3. Submerged in water or in a wet environment *Note: Always be sure the person’s chest is dry before applying pads
  4. Near or has been in contact with flammable substances, such as gasoline or propane
  5. A pacemaker or medication patches on their chest
  6. A “Do Not Resuscitate (DNR)” bracelet or tattoo on their wrist or arm

Other things to consider when you should NOT use an AED are the device’s pads. Electrode pads come in various types, including pads specifically for infants and children. If the victim is a child, do not use a defibrillator until you have attached pediatric pads to the unit instead of adult pads. Pediatric pads will ensure the appropriate shock level is given to a child under the age of 8 or 55 lbs or less.

These sticky pads have an adhesive that delivers the shock waves from the unit to the person. If the victim has a hairy chest, it may interfere with AED pad adhesion. Many AEDs are usually paired with some type of response kit that will contain a razor to move any hair that may prevent the pads from sticking.


When to Use CPR, an AED, or Both

Cardiopulmonary resuscitation (CPR) is a critical lifesaving technique that helps maintain blood flow and oxygenation to a person’s vital organs. When an AED is not immediately available, CPR can keep the heart pumping until emergency medical services arrive with an AED. CPR involves chest compressions and rescue breaths to support circulation and breathing.

Both CPR and AED use should be utilized on a cardiac arrest victim, but before performing either, it’s vital to assess if a person is unresponsive and not breathing normally. If that is the case, dial an emergency services number (such as 911, 112, or the local EMS) to call for help and ask someone nearby to find an automated external defibrillator.

If an AED is not immediately available, or if there is a delay in obtaining one, start initiate CPR. When an automated external defibrillator is immediately available, it should be used in conjunction with CPR. Instructions will be given from the AED on whether to use CPR or deliver an electric shock from a defibrillator.

Automatic defibrillators will deliver a shock automatically, while semi-automatic devices require a button to be pushed to deliver the shock. After a shock is delivered, CPR with chest compressions should be continued until the unit prompts otherwise.


How to use an Automated External Defibrillator (AED)

After understanding when to use an AED, it’s important to know how to use an AED. A defibrillator can keep a person suffering from cardiac arrest alive until medical professionals and an ambulance arrives. If used properly, this small portable machine can increase survival rates and save lives.

Even though using an AED is for anyone, even those without training, it helps to understand the steps before an emergency arises. Following the steps below on How to Use an AED:

Step 1: Call 911

Once it is determined that the person is not breathing or responsive, call 911 immediately or have someone nearby call 911, while you continue to do the following steps.

Step 2: Check Your Surroundings

Ensure the area around a person is safe for the use of an AED. Check for any water or metal surfaces that may be dangerous when using an AED.

Step 3: Power On the AED

Turn on the AED either by lifting the lid, pressing the power button, or removing the pads and begin to follow the AED Prompts.

Step 4: Remove Clothing from Victim’s Chest

Remove or cut all clothing away from the chest. Do not be afraid to cut or tear clothing if needed.

Note: Most rescue kits include shears strong enough to cut through cloth and wire materials, such as in a woman’s bra.

Step 5: Attach AED Pad to Victim’s Chest

Peel off the backing of the AED pads to expose the sticky adhesive and press firmly to the person’s clean, bare, dry skin. Visual guides on the pads or packaging will show proper placement as this varies from adult to child and infant victims.

Step 6: Connect Pads to AED

Plug the pad cables into the AED if it is not already attached to the device. This will allow the AED to monitor the person’s heart rhythm.

Step 7: Clear the Victim’s Surrounding

Sometimes during emergency situations, crowds begin to form. It is essential to sit back away from the person’s body and instruct others to do the same. Ensure you are not touching the person so as not to interfere with the analysis of their heart rhythm.

Step 8: Follow the AED’s Prompts

If the AED advises a shock, be sure no one is touching the person. For fully automatic AEDs, a button does not need to be pushed, and a shock will automatically be given. However, semi-automatic AEDs will advise you that a shock is required at this time, and then you press the shock button. If the AED does not advise a shock, follow the voice and/or visual prompts for performing CPR until emergency services arrive.


How to perform CPR

An AED will prompt you when to initiate CPR. Even though anyone can do CPR, it helps to understand the steps before an emergency arises, as emergency situations can often be chaotic. To begin CPR, follow these steps:

Step 1: Check for responsiveness

You must determine whether the person is responsive before CPR on a person. Tap the person’s shoulder and ask if they are okay. If there is no response, call 911 or ask someone nearby to call and get an AED (if one is available) while you move on to step 2.

Step 2: Open the Airway and Check for Breathing

Next, you need to open the victim’s airway. Gently tilt the head back and lift the chin to open the airway. You can check to see if the victim is breathing by placing your ear near the person’s mouth or nose. Look for chest movement and listen for breathing sounds. If the person is confirmed not breathing, you know it’s time to start CPR.

Step 3: Perform Chest Compressions

Kneel beside the person and place the heel of one hand in the middle of the chest, between the nipples on the lower half of the sternum (breastbone). Clasp the other hand on top of the first hand and pull the fingers upward. Lean over and press down hard and fast. Aim for a depth of about 2-2.4 inches and a rate of 100 to 120 beats per minute.

Step 4: Perform Rescue Breaths

After 30 compressions, give two rescue breaths. Tilt the person’s head back, pinch their nose, and give two slow breaths, each lasting about one second. Note: If you are not comfortable with giving rescue breaths, you can perform hands-only CPR by doing compressions without breaths. This is still an effective way to keep blood flowing until help arrives.

Step 5: Repeat Steps 3 & 4

Continue the cycle of 30 compressions followed by two breaths until help or an Automated External Defibrillator (AED) arrives.


Using an AED & CPR together

Using an AED & CPR together is a powerful combination. When an AED is available, it should be used along with CPR for the best outcome. When a cardiac arrest emergency arises, the best scenario is to begin CPR, while another person retrieves the AED and powers it on.

Once the pads are in place, the device will analyze the person’s heart rhythm and deliver an electrical shock if necessary. Immediately after, resume CPR as instructed by the AED. Following the step-by-step instructions, whether visually or vocally, from the defibrillator throughout the entire process to ensure you are using an AED & CPR together most effectively.


CPR vs. AED training

Although CPR and using an AED can be done by anyone, even those without medical training, taking a CPR or AED training course can create confident rescuers that are quick to act during an emergency to help save lives.

CPR training equips individuals with the skills to:

  • Assess a person’s condition
  • Perform chest compressions
  • Learn how to give rescue breaths

AED training teaches individuals how to:

  • Understand if an AED is needed based on a person’s condition
  • Prep a person for a shock using AED pads
  • Turn on and confidently handle an AED unit
  • Use the device correctly and safely in conjunction with CPR


Familiarizing yourself with the proper resources, techniques, and training can help when determining whether or not you need an AED, CPR, or both in an emergency situation. The key with any emergency is to act fast. Prompt action of both CPR and an AED together can be life-saving when it comes to sudden cardiac arrest.

AEDs should be accessed and used within 10 minutes to increase the chances of survival in a cardiac arrest victim. Educating yourself on the steps and investing in training courses can help you feel confident, act quick if an emergency arises, and potentially save a life.

Let AED.com help you be the confident hero when every second counts. We’re here for you, so you can be there for others. Contact us today at 800-544-0004 or fill out our contact us form.


2 Responses to “When and When Not To Use an AED”

December 19, 2023 at 9:53 am, David McGinty said:

Can an AED be used when the person is laying on a metal floor?


February 06, 2024 at 10:30 am, gabrielle said:

Hi David! If possible, it’s best to move the patient to an area that is not on metal flooring. However, if that is the only option, best practices are to keep the electrode pads away from contact with the conductive surface and be sure no one is touching the victim when shock happens. For more questions, please contact your manufacturers, as devices do vary.


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