How to use an AED (Automatic External Defibrillator)

AEDs (Automatic External Defibrillators), when used within the first 3-5 minutes of a person suffering a Sudden Cardiac Arrest (SCA) can dramatically increase a victims chance of survival from currently what is currently less 5% to as much as 70% and higher with a defibrillator on the scene. AEDs were designed to be used by virtually anyone with little or no experience.

An AED will automatically analyse the heart rhythm of a pulse less victim and, if the victim is in ventricular fibrillation (VF) or ventricular tachycardia (VT), shock the victim's heart in an attempt to restore its rhythm to normal. AEDs will not shock patients who do not require a shock.

When a heart is in VF, it is still receiving nerve impulses from the brain. These impulses are simply firing so chaotically that the heart cannot produce a "beat;" it cannot expel enough blood to keep the circulatory system flowing through the body. Brain cells begin to die after 4-6 minutes of oxygen deprivation.

The heart will continue its uncoordinated twitching or fluttering until it is no longer receiving electrical impulses from the brain and thus stops all together, or until the heart is shocked back into a normal rhythm, which is where an AED comes in. An AED stops the heart from its spasm by shocking it. This allows the nerve impulses a chance to resume their normal pattern, which, in turn, allows the heart to resume beating at its normal pace.

The ONLY definitive treatment for ventricular fibrillation (VF) is DE -FIBRILLATION

Note: AEDs are NOT for use on children under the age of 1, or victims that have a pulse.
chain of survival


The AED will guide you through the entire process until help has arrived.

Follow the visual & voice prompts of the AED

1. Call 000.

If you see someone collapse, immediately call 000 and get the paramedics en route. If there are other people around, choose someone specific and instruct them to call 000 and explain the situation. This decreases confusion about who should do what and ensures that the call is being placed.

2. Check the victim's breathing and airway.

If someone has collapsed, you should immediately determine whether they are breathing. If the victim is breathing, you know that they have a pulse. If the victim is not breathing, check the airway is clear then begin CPR at 2 breaths then 30 chest compressions at a depth of 4-5cm.

3. Locate an AED.

If there is an AED nearby, ask a bystander to take over CPR while you apply the AED chest electrode pads to the victim. Uninterrupted CPR is an important factor in increasing the recovery rate of cardiac arrest patients. Always ensure that someone is providing CPR for the victim unless the AED machine is actively analysing or shocking the victim.

4. Turn on the AED.

Follow the visual & voice prompts of the AED

5. Attach the electrode pads to patients bare chest. (Expose the patients bare chest, male or female)

First ensure that the adhesive AED pads are attached to a cable, which is plugged into the AED machine. Then bare the victim's chest including females and attach the adhesive AED pads in the appropriate locations. The AED should include a diagram (typically on the adhesive pads themselves) indicating where each pad goes. The ZOLL Aed uses a one-piece chest pad that makes placement easy.

6. Always follow the instructions of the AED.

CPR should not be interrupted while the adhesive electrode pads are being applied.

Female Electrode Pads  
Zoll One-Piece Pads         Two Piece Pads Position
Male Electrode Pads
Zoll One-Piece Pads         Two Piece Pads Position

Analaysing the victims’ heart rhythm.

The AED may instruct you to “Stop CPR, do not touch patient, analysing”. The rescuer will then say "CLEAR!" to ensure that nobody is touching the victim while the AED analyses the victims heart rhythm. A shock is only indicated if the victim's heart is in ventricular fibrillation (VF) or ventricular tachycardia (VT). The AED will automatically analyse the heart rhythm of the victim and inform you, the rescuer, whether a shock is advised.

If you get a "no shock advised" instruction from the AED it can mean:

Follow the visual & voice prompts of the AED

Delivering a shock to the victim.

If the AED indicates that a shock is required, make sure that everyone is “CLEAR” of the victim. Tell everyone assisting you to stay clear of the victim and ensure that you are clear of the victim as well. Then press the shock button on the AED machine to deliver the first shock. (Fully automatic AED will shock the victim automatically) Immediately following the shock, begin 2 minutes of CPR as instructed by the AED.

: Do not remove the AED chest pads while performing CPR.

Follow the visual & voice prompts of the AED

Check the victim's rhythm.

After 2 minutes the AED will say “Stop CPR, analysing” The AED is now analysing the victim to see whether a shockable rhythm is present and instruct you again either “ Shock advised” or “No Shock advised”, continue CPR in intervals of 2 mins or until help arrives.

If the AED gives a "no shock advised" message after any analysis, check the victim's pulse and breathing. If a pulse is present, monitor the victim's airway and provide rescue breathing as needed.

Follow the visual & voice prompts of the AED


Do not use on children below 8 years (or 40 kg unless using paediatric (child) electrode pads.
Do not use on conductive surfaces - water - fluids - metals
Do not operate an AED if under the effects of ALCOHOL or DRUGS
Do not touch patient when shock therapy is being delivered.
Do not use in an explosive environment, eg oxygen enriched, gaseous or fume environment

There are many different AED designs, but all are created with simplicity in mind. Many models will audibly instruct the rescuer about exactly what to do during each step of the process (i.e. “stand back” and “check breathing and pulse”). Some will even deliver the shocks automatically. As long as you understand the general principles behind an AED, you may be able to save someone’s life.

Zoll AED Plus Demonstration


  1. Confirm patient is unconscious, no breathing, no pulse.
  2. Turn on the AED and follow the voice & visual prompts.
  3. Attach electrode pads to patient’s bare chest (male or female) as indicated.
  4. Stop CPR and do not touch patient while AED analysing.
  5. Deliver a shock by pressing flashing red light if indicated.
  6. Continue 2 mins cycles CPR between shocks if victim is still not breathing until help arrives.