Resource: First Aid & CPR

Using an AED (automated external defibrillator)

An automated external defibrillator (AED) is a lightwieght, portable, computerized device that can identify an abnormal heart rhythm that needs a shock. The AED can then deliver a shock that could help restore a normal heart rhythm. AEDs are simple to operate enabling bystanders to give lifesaving treatment.

Being familiar with your AED will boost confidence.

AED equipment varies according to the model and manufacturer. That being said most operate in the same way. So, know where the nearest AED is located. Have you access to it, do you need a key? Does it have child options and are scissors, gloves etc. included?

Using an AED - Step 1.

Open the carrying case. Power on the AED. 

  • Some devices will ‘power on’ automatically when you open the lid or case
  • Follow the AED prompts as a guide to the next steps
Step 2.

Attached AED pads to the victims bare chest. 

  • Peel the backing away from the AED pads
  • Attach the adhesive AED pads to the victims bare chest. Follow the placement diagrams on the pad. 
  • Attach the AED cable to the device (note, most often the pads are already connected to the AED)
Step 3.

Clear the victim and allow the AED to analyze the rhythm

  • When the AED prompts you, clear the victim during analysis. Be sure that no one is touching the victim, not even the rescuer in charge of giving breaths.
  • The AED may take a few seconds to analyse.
  • The AED tells you if a shock is needed.
Step 4.

If the AED advises a shock, it will tell you to clear the victim and then deliver a shock.

  • Clear the victim before delivering the shock, be sure that no one is touching the victim.
  • Loudly state a ‘clear’ message such as “Everbody clear ” or simply “Clear”.
  • Look to be sure that no one is in contact with the victim.
  • Press the shock button.
  • The shock will produce a sudden contraction of the victims muscles.
Step 5.

If no shock is needed, and after any shock delivery, immediately resume CPR, starting with chest compressions.

Step 6.

After about 5 cycles or 2 minutes of CPR, the AED will prompt you to repeat steps 3 and 4.

Make sure to maintain your AED.

AEDs should be properly maintained according to the manufacturers instructions. This can include, battery replacement, Pad replacement and provision of additional medical equipment - scissors, razor, wipes and gloves.

Special Circumstances

Special circumstances may require the rescuer to take additional actions when placing AED pads.

Hairy Chest.

If the victim has a hairy chest, the AED pads may stick to the hair and not to the skin on the chest. If this occurs, the AED will not be able to analyze the victims heart rhythm. 


If the victim has a hairy chest, you should shave the area where you will place the pads by using a razor from the carrying case. 


Water is a good conductor of electricity. Do not use the AED in water.

  • If the victim is in water, pull them out so long as it is safe for you to do so.
  • If the victims chest is covered in water, quickly wipe the chest before attaching the AED pads.
  • If the victim is lying on snow or in a small puddle, you may use the AED after quickly wiping the chest.
Implanted Defibrillators and Pacemakers.

Victims with a high risk of cardiac arrest may have implanted defibrillators or pacemakers that automatically deliver shocks directly to the heart. If you place an AED pad directly oevr an implanted medical device, the implanted device may block delivery of an effective shock to the heart.


These devices are easy to identify because they create a hard lump beneath the skin of the upper chest or abdomen. 


If you identify an implanted defibrillator/pacemaker – 

  • If possible, avoid placing the AED pad directly over the implanted device.
  • Follow the normal steps for operating an AED.
Transdermal Medication Patches.

Do not place AED pads directly on top of a medication patch. The medication patch may block the transfer of energy from the AED pad to the heart and also cause small burns to the skin. Examples of medication patches are nitroglycerin, nicotine, pain medication, and hormone replacement therapy patches.


If it does not delay delivery, remove the patch using gloved hands and wipe the area before attaching the AED pad.

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