How to use a defibrillator

Defibrillators are very easy to use. Although they don’t all look the same, they all function in broadly the same way. The machine gives clear spoken instructions. You don't need training to use one.

Watch this short film and learn how a defibrillator works.

  • If you come across someone who is not breathing or breathing erratically, the most important thing is to call 999 and start CPR to keep the blood flowing around the body. After a cardiac arrest, every minute without CPR and defibrillation reduces someone's chance of survival by 10 per cent.
  • If you're on your own, don't interrupt the CPR to go and get a defibrillator. If it's possible, send someone else to find one. When you call 999, the operator can tell you if there's a public access defibrillator nearby.
  • Once the defibrillator is open and in position, all you have to do is follow the spoken instructions. Many defibrillators will also have diagrams or a screen to help you. The defibrillator detects the heart's rhythm, it won't deliver a shock unless one is needed.

  • Often you’ll need to press the shock button although some fully automatic defibrillators will deliver the shock themselves. You should resume CPR as soon as instructed by the defibrillator.

Learn CPR with our Heartstart courses

Heartstart courses teach you CPR and other emergency lifesaving skills and they are free to attend.

There are over 1,700 Heartstart schemes across the UK supported by the BHF

Visit our Heartstart courses page to find out more.