CPR step by step and how to use a defibrillator (AED)

Cardiac arrest can strike anywhere: on the street, at the gym, at home. In the first minutes, the person’s only chance is someone nearby who starts compressions and brings a defibrillator. Every minute without CPR sharply reduces the chance of survival. You don’t need to be a doctor: you need to know three things and not be afraid to do them.

The steps below follow the European resuscitation guidelines updated in 2025, as published for the public by Resuscitation Council UK. In North America, the American Heart Association’s guidance is essentially the same. This doesn’t replace a hands-on first aid course with a practice manikin, but it can help you save a life until you take one.

1. Check

• Make sure the scene is safe for you (traffic, electricity, fire).
• Speak loudly and gently shake their shoulders: “Can you hear me?”

2. Call for help

• If they don’t respond, call the emergency number at once and put the phone on speaker beside you.
• Check breathing: watch the chest for no more than 10 seconds. Abnormal breathing means cardiac arrest: occasional gasps, slow labored breaths or panting. A few seconds of seizure-like movements can happen at the start of an arrest; once they stop, check breathing again.
• If someone is with you, send them to look for a defibrillator.
• The call handler will guide you step by step. Follow their instructions.

3. Chest compressions

1. The person should lie on their back on a firm surface (the floor, not a bed).
2. Put the heel of one hand on the lower half of the breastbone, in the center of the chest, and the other hand on top, fingers interlocked.
3. Arms straight, shoulders directly over your hands.
4. Push down 5–6 cm (2–2.4 in), at 100–120 compressions a minute (the beat of “Stayin’ Alive”).
5. Let the chest come all the way back up between compressions and avoid unnecessary pauses.

Rescue breaths: if you’re trained and confident, give 30 compressions, then 2 breaths, and repeat. If not, do compressions only, continuously. The call handler will assume you’re untrained and give compression-only instructions anyway.

CPR is exhausting. If someone else is there, swap every 2 minutes without a gap.

4. The defibrillator (AED)

• Anyone can use it, without training. It analyzes the heart rhythm itself and only shocks if needed.
• Open it or press the power button and follow the spoken instructions.
• Stick the pads on the bare chest exactly as the picture on them shows. If there are two of you, one keeps doing compressions while the other applies the pads.
• While it analyzes or shocks, nobody touches the person.
• After a shock, or if it says no shock is needed, restart compressions immediately.

How long to keep going

Until paramedics arrive and take over, until the person starts breathing normally, or until you physically can’t go on. If they recover and breathe normally, roll them onto their side (the recovery position) and stay with them.

Afterwards

It’s normal to be shaken after attempting CPR, however it ended. Talk to someone close about what happened. The 2025 guidelines explicitly recognize that bystanders may need support too.

A good first aid kit at home and in the car helps in other emergencies too: see what to put in a first aid kit.