Quick answer — what are the 4 links in the chain of survival?

The chain of survival is a sequence of four critical actions that, when performed in order, give a cardiac arrest victim the best chance of survival:

1. Early recognition and call for help — recognise cardiac arrest and call Triple Zero (000) immediately
2. Early CPR — begin chest compressions within minutes to maintain blood flow to the brain and heart
3. Early defibrillation — use an AED (automated external defibrillator) as soon as one is available
4. Early advanced care — paramedics and hospital teams provide advanced life support and post-resuscitation treatment

Every link depends on the one before it. If any single link is weak, delayed, or missing, survival rates drop dramatically. Bystander CPR and early defibrillation — links 2 and 3 — are the links that ordinary Australians can directly influence through training. This is what you learn in HLTAID009 Provide CPR ($45, 2 hours) and HLTAID011 Provide First Aid ($95, 4 hours).

Why the chain of survival matters in Australia

Each year approximately 25,000 Australians experience an out-of-hospital cardiac arrest. Without bystander intervention, only about 12% survive. With immediate CPR and an AED applied within 3–5 minutes, survival rates can reach 74%.

The gap between 12% and 74% is the chain of survival. Every minute without CPR reduces the chance of survival by 7–10%. After 10 minutes without intervention, survival is almost impossible.

In many parts of Australia, paramedic response times average 8–15 minutes depending on location. In rural and regional areas, it can be significantly longer. That means the first two bystander-controlled links — early CPR and early defibrillation — are the only things keeping a cardiac arrest patient alive until professional help arrives.

This is not theoretical. In communities with high rates of bystander CPR training, cardiac arrest survival rates are measurably higher. The chain of survival is the framework that makes this possible.

Link 1 — Early recognition and call for help

The first link requires recognising that someone is in cardiac arrest and activating the emergency medical system immediately. Cardiac arrest is not always dramatic — a person may simply collapse without warning, or they may stop responding during a conversation.

How to recognise cardiac arrest

• The person is unresponsive — they do not react to voice or touch
• They are not breathing normally — absent breathing, or gasping/gurgling sounds (agonal breathing)
• There is no pulse (though checking a pulse is unreliable for untrained rescuers — focus on breathing)

Agonal breathing is the single most common cause of delayed CPR. It looks like occasional gasping, snoring, or gurgling — not smooth, regular breathing. If you are unsure whether someone is breathing normally, treat them as not breathing and begin CPR. This is covered in detail in the DRSABCD guide.

How to activate the emergency system

Call Triple Zero (000) immediately — or direct a specific bystander to call. Say: "You in the blue shirt — call 000 now and come back to tell me what they said." This eliminates the bystander effect, where everyone assumes someone else has already called.

Tell the 000 operator your exact location, that the person is unresponsive and not breathing, and whether you have started CPR. Stay on the line — the dispatcher will guide you through CPR if needed.

Direct a second bystander to find the nearest AED. AEDs are commonly found in shopping centres, sporting venues, airports, schools, libraries, and council buildings. The GoodSAM app can help locate the nearest registered AED.

Link 2 — Early CPR

CPR (cardiopulmonary resuscitation) is the second link and the most critical action a bystander can take. When the heart stops pumping, CPR manually circulates blood to the brain and vital organs, buying time until defibrillation and advanced care can restart the heart.

CPR technique summary

• Place the heel of one hand on the centre of the chest (lower half of the breastbone), other hand on top, fingers interlocked
• Lock your elbows and press straight down with your body weight
• Compress to a depth of 5–6 cm for adults (one-third of chest depth for children and infants)
• Compress at a rate of 100–120 per minute — the rhythm of “Stayin’ Alive” by the Bee Gees
• Give 30 compressions followed by 2 rescue breaths (if trained and willing)
• If you are unable or unwilling to give rescue breaths, continuous chest compressions alone are far better than doing nothing
• Minimise interruptions — every pause in compressions reduces blood flow
• If multiple rescuers are present, swap every 2 minutes to prevent fatigue-related compression depth loss

CPR quality matters enormously. The Australian Resuscitation Council’s 2026 guidelines emphasise that hard, fast, uninterrupted compressions are the single most important factor in CPR survival outcomes. Shallow compressions, slow rates, or frequent pauses significantly reduce effectiveness.

This is why hands-on training matters — reading about CPR is valuable, but practising on a mannequin with a qualified instructor builds the muscle memory and confidence to act under pressure. HLTAID009 Provide CPR teaches this in a 2-hour face-to-face session for $45.

Link 3 — Early defibrillation

An AED (automated external defibrillator) analyses the heart’s rhythm and delivers an electrical shock if a shockable rhythm is detected. For the two shockable cardiac arrest rhythms — ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) — defibrillation is the definitive treatment. CPR alone cannot restart the heart; it only maintains circulation until the AED or paramedics can intervene.

Why timing matters

For every minute that defibrillation is delayed, the chance of successful shock decreases by approximately 10%. If an AED is applied within 3 minutes of collapse, survival rates can exceed 70%. After 10 minutes, the chance of a successful shock is minimal.

This is why the chain of survival emphasises "early" at every step. CPR bridges the gap between cardiac arrest and defibrillation, but the AED is what actually restores a normal heartbeat in the majority of survivable cases.

How to use an AED

AEDs are designed for use by anyone — no medical training is required. The device provides voice prompts that guide you through every step:

1. Turn on the AED — most activate when you open the lid
2. Attach the electrode pads to the bare chest — one below the right collarbone, one under the left armpit
3. Stand clear while the AED analyses the heart rhythm — ensure nobody is touching the patient
4. If a shock is advised, press the shock button when prompted (some AEDs deliver automatically)
5. Immediately resume CPR after the shock — do not wait to see if the patient responds
6. Continue CPR and AED cycles until paramedics arrive

An AED cannot harm a patient with a normal heartbeat — it will only deliver a shock if a shockable rhythm is detected. There is no risk of "shocking someone who doesn’t need it." This is one of the most important facts to understand, because fear of causing harm is the primary reason bystanders hesitate to use AEDs.

AED training is included in both HLTAID009 Provide CPR and HLTAID011 Provide First Aid.

Link 4 — Early advanced care

The fourth link is delivered by paramedics and hospital emergency teams. It includes advanced airway management, intravenous medications (adrenaline, amiodarone), continuous cardiac monitoring, targeted temperature management, and post-resuscitation care in a cardiac catheterisation lab or intensive care unit.

While bystanders cannot provide this level of care, the quality of links 1 through 3 directly determines whether the patient arrives at hospital with a viable chance of recovery. Effective bystander CPR and early defibrillation are the foundation that makes advanced care possible.

How to strengthen the chain of survival in your community

Get CPR trained — and renew annually

The Australian Resuscitation Council recommends annual CPR training to maintain competency. Skills degrade without practice — research shows that CPR quality declines significantly within 3–6 months of training. Annual renewal through HLTAID009 ($45, 2 hours) keeps your skills sharp.

Know your nearest AED

Walk through your workplace, shopping centre, gym, sports club, and children’s school. Locate the AED. Note where it is. In an emergency, the difference between knowing where the AED is and having to search for it is measured in minutes — and in cardiac arrest, minutes determine survival.

Encourage workplace compliance

Under the Work Health and Safety Act 2011, every Australian workplace must have trained first aiders. The Heart Foundation recommends AED placement in all workplaces with 20 or more employees. If your workplace doesn’t have an AED or current first aiders, raise it with your WHS officer.

Get CPR certified at our North Brisbane venues

Be a link in the chain of survival. IRFA delivers nationally accredited CPR training (HLTAID009, $45, 2 hours) and comprehensive first aid (HLTAID011, $95, 4 hours) at four venues across North Brisbane:

Redcliffe Peninsula — Redcliffe RSL

Irene Street, Redcliffe QLD 4020. On-site parking. Serving Redcliffe, Scarborough, Kippa-Ring, Margate, and Woody Point.

North Lakes — Community Centre

10 The Corso, North Lakes QLD 4509. Near Westfield. Serving North Lakes, Mango Hill, Griffin, Dakabin, and Kallangur.

Virginia / Northgate — Northgate Hall

34 Ridge Street, Virginia QLD 4014. 5 minutes from Northgate Station. Serving Virginia, Banyo, Nudgee, and Nundah.

Caboolture — Caboolture Hub

4 Hasking Street, Caboolture QLD 4510. Near train station with free parking. Serving Caboolture, Morayfield, and Burpengary.

Same-day certificates. Paramedic trainers. Sessions 7 days a week from 7 AM. View all North Brisbane courses →

Frequently asked questions

What are the 4 links in the chain of survival?

The four links are: (1) early recognition and call for help — call 000, (2) early CPR — begin chest compressions, (3) early defibrillation — apply an AED, and (4) early advanced care — paramedic and hospital treatment. Each link depends on the one before it.

Why is the chain of survival important?

Without bystander intervention, only about 12% of out-of-hospital cardiac arrest patients survive in Australia. With early CPR and defibrillation within 3–5 minutes, survival can reach 74%. The chain of survival is the framework that connects each step to maximise the patient’s chance of recovery.

Which links in the chain can a bystander perform?

Links 1, 2, and 3. A bystander can recognise cardiac arrest and call 000 (link 1), begin CPR (link 2), and apply an AED (link 3). Link 4 — advanced care — is provided by paramedics and hospital staff. The quality of bystander actions in links 1–3 directly determines the outcome of link 4.

How long can someone survive without CPR during cardiac arrest?

Brain damage begins within 4 minutes of cardiac arrest without CPR. After 10 minutes without intervention, survival is almost impossible. CPR extends this window by maintaining blood circulation to the brain and heart until defibrillation or advanced care can be provided.

Is the chain of survival taught in first aid courses?

Yes. The chain of survival is a foundational concept in both HLTAID009 Provide CPR ($45, 2 hours) and HLTAID011 Provide First Aid ($95, 4 hours). IRFA teaches it at four North Brisbane venues — Redcliffe, North Lakes, Virginia/Northgate, and Caboolture — with same-day certification under RTO 32154.

Where can I find an AED near me?

AEDs are commonly located in shopping centres, airports, sporting venues, schools, libraries, and council buildings. The GoodSAM app and the Heart Foundation’s AED registry can help you locate the nearest registered defibrillator. Ask your workplace WHS officer whether your building has one.