First Aid Tips, Information & Advice - St John Ambulance

How to do CPR on an adult

If an adult is unresponsive and not breathing normally, you need to call 999 or 112 for emergency help and start CPR straight away. Learn what to do.

What is CPR?

CPR stands for cardiopulmonary resuscitation. It combines chest compressions and rescue breaths to give a person the best chance of survival following a cardiac arrest. If an adult is unresponsive and not breathing normally, you need to call 999 or 112 for emergency help and start CPR straight away.

Watch our video - Adult CPR

What to do

1. If you find someone collapsed, you should first perform a primary survey. If you have established from this that they are unresponsive and not breathing, you should ask a helper to call 999 or 112 for emergency help while you start CPR. Ask a helper to find and bring a defibrillator, if available.

• If you are on your own, use the hands-free speaker on a phone so you can start CPR while speaking to ambulance control.
• Do not leave the casualty to look for a defibrillator yourself. The ambulance will bring one.

First aid - call 999 or 112 for emergency help

2. Start CPR. Kneel by the casualty and put the heel of your hand on the middle of their chest. Put your other hand on top of the first. Interlock your fingers making sure they don't touch the ribs.

Keep your arms straight and lean over the casualty. Press down hard, to a depth of about 5-6cm before releasing the pressure, allowing the chest to come back up.

Cardiac arrest first aid - start CPR

3. Repeat the compressions 30 times; at a rate of 100-120 compressions per minute.

• The beat of the song ‘Staying Alive’ can help you keep the right rate.

Cardiac arrest first aid - repeat compressions 30 times

4. After 30 compressions, you need to give two rescue breaths. To do this, open the airway by placing one hand on the forehead to tilt the head back and use two fingers from the other hand to lift the chin.

Cardiac arrest first aid - give two rescue breaths

5. Take the hand from the forehead and pinch the soft part of the nose closed. Allow the mouth to fall open. With the head still tilted, take a breath in and place your mouth over the casualty’s forming a seal. Blow into their mouth for one second, until the chest rises. Take your mouth away and watch the chest fall.

• If the chest doesn’t rise, check the airway is open.
• If you are not trained or do not feel comfortable performing rescue breaths, give continuous chest compressions.

Cardiac arrest first aid - blow into their mouth for one second, until the chest rises

6. Continue to perform CPR, alternating 30 chest compressions with two rescue breaths, (30:2) until:  

• emergency help arrives and takes over  
• the person starts showing signs of life and starts to breathe normally
• you are too exhausted to continue (if there is a helper, you can change over every one-to-two minutes, with minimal interruptions to chest compressions)
• a defibrillator is ready to be used.

Cardiac arrest first aid - repeat compressions 30 times

7. If the helper returns with a defibrillator, ask them to switch it on and follow the voice prompts while you continue with CPR.

Cardiac arrest first aid - apply the pads

8. If the casualty shows signs of becoming responsive such as coughing, opening eyes, speaking, and starts to breathe normally, put them in the recovery position. Monitor their level of response and prepare to give CPR again if necessary.