How to use a defibrillator (AED), step by step
Automated external defibrillators (AEDs) are now in shopping centres, gyms, sports clubs, schools and offices all over Queensland. But when someone collapses, many people walk straight past the AED on the wall because they’re worried they’ll use it wrong. The truth is that AEDs are designed for complete beginners. Here’s exactly how to use one.
This guide follows the Australian and New Zealand Committee on Resuscitation (ANZCOR) guidelines. It's not a substitute for hands-on training. In an emergency, always call Triple Zero (000) first.
What does an AED do?
In a sudden cardiac arrest, the heart’s electrical system often goes into a chaotic rhythm called ventricular fibrillation. The heart quivers instead of pumping, and no blood reaches the brain. An AED analyses the heart’s rhythm and, if it detects a shockable rhythm, delivers an electric shock to reset it.
Every minute without CPR and defibrillation reduces the person’s chance of survival. Ambulances do an incredible job, but they take time to arrive. Bystanders who start CPR and use an AED in those first few minutes give the person the best chance of surviving.
When should you use an AED?
Use an AED on anyone who is unresponsive and not breathing normally. Occasional gasping breaths (called agonal breathing) are common in the first minutes of a cardiac arrest. They are not normal breathing, so treat the person as being in cardiac arrest.
Step by step: how to use an AED
Follow DRSABCD, the action plan you’ll learn in every First Aid and CPR course.
1. Danger. Check the area is safe for you, bystanders and the casualty.
2. Response. Talk to the person and squeeze their shoulders. If there’s no response, they’re unresponsive.
3. Send for help. Call Triple Zero (000), or ask someone else to call and put the phone on speaker. Send another person to find the nearest AED and bring it back. The 000 operator can talk you through CPR while you wait.
4. Airway. Open the mouth and check for anything blocking the airway. If you see something, roll them onto their side and clear it. Then tilt the head back and lift the chin.
5. Breathing. Look, listen and feel for normal breathing for up to 10 seconds. If they’re not breathing normally, start CPR straight away.
6. CPR. Give 30 chest compressions followed by 2 breaths. Push hard and fast in the centre of the chest, about one third of the depth of the chest (more than 5 cm on an adult), at 100 to 120 compressions per minute. If you can’t or won’t give breaths, keep doing compressions without stopping.
7. Defibrillation. As soon as the AED arrives, use it:
- Turn it on. Open the lid or press the power button. From this point the AED talks you through every step.
- Expose the chest. Remove or cut clothing. Wipe the chest if it’s wet, and remove any medication patches from where the pads go.
- Attach the pads. Peel off the backing and place the pads exactly as shown on the pictures. On an adult, one pad goes on the upper right chest, below the collarbone. The other goes on the left side of the chest, below the armpit.
- Stand clear. The AED will tell everyone not to touch the person while it analyses the heart’s rhythm. Say it out loud: “Stand clear!”
- Shock if advised. If the AED advises a shock, make sure nobody is touching the person and press the shock button. Fully automatic AEDs deliver the shock themselves after a countdown.
- Resume CPR when prompted. After the shock, or if no shock is advised, the AED will tell you to continue CPR. Start compressions again straight away.
Keep going: the AED will re-analyse the rhythm at regular intervals and tell you what to do. Don’t turn the AED off or remove the pads, even if the person starts to recover, and continue until paramedics take over or the person starts breathing normally.
Using an AED on children and infants
An AED can be used on children and babies. Standard adult pads are suitable for children over 8. For children under 8 and infants, paediatric pads, or an AED with a child mode, are ideal because they reduce the energy of the shock. If neither is available, use the adult pads. Don’t delay defibrillation looking for child pads.
If the pads would touch or overlap on a small child, place one in the centre of the chest and the other in the centre of the back, between the shoulder blades.
Special situations
- Water. Move the person out of the water and away from any pooled water, and dry their chest quickly before attaching the pads. The pads need dry skin to stick and work properly.
- Pacemakers and implanted devices. You’ll often see a lump under the skin on the upper chest. Place the pad at least 8 cm away from it, never directly over it.
- Chest hair. If the pads aren’t sticking, press them down firmly. Many AED kits include a razor for this reason.
Common myths about AEDs
“I could shock someone who doesn’t need it.” An AED will only allow a shock if it detects a shockable rhythm. If the person’s heart doesn’t need a shock, it won’t deliver one.
“I could make things worse.” A person in cardiac arrest is clinically dead. Doing CPR and using an AED can only improve their chances.
“I need training to use one.” Training makes you faster and more confident, but anyone can follow the voice prompts. AEDs are designed for members of the public.
“An AED restarts a heart that has stopped.” Not quite. An AED treats chaotic rhythms like ventricular fibrillation. If the heart has no electrical activity at all, the AED will advise no shock, and good CPR becomes even more important.
Where to find an AED
AEDs are increasingly common in workplaces, shopping centres, gyms, sporting clubs, schools, pools and airports. They’re usually in a green or orange box with a heart symbol and a lightning bolt. Take a moment next time you’re at work or the gym to look for where the nearest one is kept. If you ever need it, you’ll already know.
If you run a business, an AED is a worthwhile addition to your First Aid kit, especially in a high-risk workplace or one with lots of visitors. See our guide to workplace First Aid requirements in Queensland.
Practise it before you need it
Reading a guide is a good start, but nothing beats hands-on practice. In our 1.5-hour CPR course you’ll practise CPR on adult and infant manikins and use a training AED until it feels natural. Courses run every week in Brisbane and on the Gold Coast for $49. AED training is also part of our First Aid course and Childcare First Aid course.