How a Defibrillator Turns 10% Survival Into 60%
An AED can be the difference between life and death in the minutes before an ambulance arrives. Every year, around 25,000 Australians suffer a cardiac arrest outside of hospital, and only less than 1 in 10 survive. That number climbs dramatically when a bystander acts fast, and an automated external defibrillator (AED) is the single most important tool for doing so. This guide explains how an AED saves lives, how the device works, and why every workplace, club, and public space should have one within reach.
Cardiac Arrest is Not a Heart Attack
This is the most important thing to understand, and it's the point most people get wrong. A cardiac arrest and a heart attack are two different emergencies.
A heart attack is a plumbing problem: a blocked artery cuts off blood supply to part of the heart muscle. The person is usually conscious, breathing, and can describe chest pain. A cardiac arrest is an electrical problem: the heart's rhythm fails and it stops pumping blood altogether. The person collapses, loses consciousness, and stops breathing normally within seconds. The Heart Foundation sets out the difference between a heart attack and cardiac arrest clearly, and it matters because the treatment is different. An AED treats cardiac arrest. A heart attack, left untreated, can trigger one.
How an AED Works
An automated external defibrillator is a portable device that analyses the heart's rhythm and, if needed, delivers a controlled electric shock to restore a normal beat. The word "automated" is the key: the machine does the thinking, so the person using it doesn't have to.
Here's what happens when you turn one on:
- The AED talks you through each step with voice and visual prompts.
- You place the pads on the person's bare chest as the diagram shows.
- The device reads the heart's rhythm and decides whether a shock is needed.
- If the rhythm is shockable, it either delivers the shock automatically or tells you to press a button.
- It then guides you through CPR, often with real-time feedback on your compressions.
The safeguard that makes an AED usable by anyone: it will only shock a heart that needs it. As healthdirect explains, an AED checks the heartbeat pattern to decide whether a shock is required, and it will not shock a normal heartbeat or a heart with no rhythm at all. You cannot accidentally hurt someone with it.
Why Every Minute Matters
Cardiac arrest survival is a race against the clock. For every minute that passes without CPR and defibrillation, the chance of survival falls by around 10%. After about 10 minutes, survival is unlikely.
That's the gap an AED fills. Ambulances are fast, but even a good response time is several minutes, and in a cardiac arrest those minutes are everything. When CPR and an AED are used within the first three to five minutes, survival can climb from around 10% to as high as 60-70%. An on-site AED, used by a bystander before the ambulance arrives, is what makes that possible.
Where AEDs Belong: The Chain of Survival
An AED works best as part of what's known as the chain of survival, the sequence that gives someone the best chance:
- Call. Ring Triple Zero (000) the moment someone collapses and isn't breathing normally.
- Push. Start CPR straight away, pushing hard and fast in the centre of the chest.
- Shock. Send someone to fetch the nearest AED and follow its prompts.
CPR alone rarely restarts a heart, but it keeps oxygen moving to the brain and buys time, keeping the heart in a state where the AED has a better chance of working. The two together are what save lives, which is why an accessible AED and some basic CPR awareness are such a powerful combination on any site.
Who Needs an AED on Site
Around 90% of cardiac arrests happen away from a hospital, and they strike without warning, in workplaces, gyms, shopping centres, schools, and sporting clubs. Anywhere people gather is a place a cardiac arrest can happen. That's the case for treating an AED like any other piece of critical safety equipment: not a nice-to-have, but a standard fixture.
For a workplace, an AED sits naturally alongside your first aid provisions and emergency response plan. Our guide on why every site should have an AED looks at the workplace case in more detail.
Choosing an AED
Modern AEDs are designed so that an untrained person can use one under pressure. When choosing, a few features matter:
- Fully automatic vs semi-automatic. A fully automatic unit delivers the shock itself; a semi-automatic one prompts you to press a button. Both are simple to use.
- CPR feedback. Some units, like the HeartSine Samaritan PAD 500P, give real-time feedback on your compression rate and depth.
- Adult and paediatric capability. Many units, including the HeartSine PAD 360P and the ZOLL AED 3, work for both adults and children.
- Durability. An IP rating tells you how well the unit resists dust and water, which matters for worksites and outdoor use.
Checkpoint supplies a range of AEDs from HeartSine and ZOLL, from the compact Samaritan PAD 350P through to CPR-feedback models. You can see the full range of defibrillators and match one to your setting.
Keeping an AED rescue-ready
An AED only saves a life if it works on the day. Mount it somewhere visible and signed, not locked in a cupboard, so anyone can find it fast. Keep the pads and battery in date, since both expire and need replacing, and check the status indicator regularly so a flat battery never catches you out. A wall cabinet protects the unit from knocks and dust while keeping it visible.
An AED is one of the few pieces of equipment that can genuinely bring someone back. If your site doesn't have one, or you're not sure the one you have is ready to use, Checkpoint can help you choose the right unit and keep it rescue-ready. Talk to our team about what suits your workplace.