What is CPR and how do you perform it?
June 05, 2024

What if a family member suddenly started clutching their chest, felt nauseous and had shortness of breath? Would you know what to do? It's so easy to learn how to help someone yet there are still so many people that aren’t trained. You’ve heard of CPR...but what exactly is it and how do you perform it?

CPR stands for cardiopulmonary resuscitation. Performing CPR can help keep blood flowing to the brain and other organs. It is easy to learn and should be performed immediately after you call 911 in the event of a medical emergency. You do not need to be a medical professional to do CPR on someone. There is also no risk of injuring a person while performing CPR.

CPR should be used when someone is experiencing a cardiac arrest. Cardiac arrest means the heart stops beating properly. With no blood flow going to the brain the casualty becomes unresponsive and stops breathing. Cardiac arrest means the casualty is clinically dead, but if CPR is started and a defibrillator (check out our post on AEDs here!) is applied quickly there is still an opportunity to restore a normal heartbeat.

Common causes of cardiac arrest include:

  • Heart attack
  • Severe injuries
  • Electrical shock
  • Drug overdose
  • Drowning
  • Suffocation


CPR is artificial respiration and artificial circulation. Artificial respiration provides oxygen to the lungs. Artificial circulation causes blood to flow through the body. The purpose of CPR is to circulate enough oxygenated blood to the brain and other organs to delay damage until either the heart starts beating again, or medical help takes over from you. CPR is most effective when interruptions to chest compressions are minimized.

Always remember the ABC acronym that represents the 3 main steps of CPR:

  • A: airway
  • B: breathing
  • C: circulation

...now you know your ABCs!

Check out this poster to learn how to perform CPR! You can also download it and print it off to refer to.

Most cardiac arrests do not happen at a hospital. Your loved one could lose their life at a moment’s notice if you don't act upon it. If you have the skills and the knowledge at your fingertips, you can make a difference. Get trained with St. John Ambulance! We’ll teach you everything you need to know to get started with first aid and CPR. View our course catalog by clicking here.