What Happens During CPR? A Comprehensive Guide

Cardiopulmonary resuscitation (CPR) is a critical life-saving technique performed during emergencies when someone's heart has stopped beating or their breathing has ceased. CPR is an essential skill that can help sustain vital organ function until advanced medical help arrives. In this comprehensive guide, we will outline the key steps and procedures involved in performing CPR, as recognized by MyCPR NOW.

1. Recognition and Assessment:
The first step in CPR is recognizing that someone requires immediate assistance. Check for responsiveness by gently tapping the person and shouting for a response. If there is no response, assess for normal breathing or signs of gasping. If the person is unresponsive and not breathing normally, activate the emergency medical services (EMS) and begin CPR immediately.

2. Chest Compressions:
Chest compressions are a vital component of CPR. To perform effective chest compressions:
- Position yourself beside the person on a firm surface.
- Place the heel of one hand on the center of the person's chest, between the nipples.
- Place your other hand on top of the first hand, interlocking your fingers.
- Keep your arms straight and position your shoulders directly above your hands.
- Press down on the chest at least 2 inches (5 centimeters) deep and at a rate of 100-120 compressions per minute.
- Allow the chest to fully recoil between compressions.

3. Rescue Breaths:
Rescue breaths are performed to deliver oxygen to the person's lungs. However, in some CPR guidelines, hands-only CPR (chest compressions without rescue breaths) is recommended for untrained individuals or in situations where rescue breaths cannot be given. If you are trained and confident in providing rescue breaths:
- Ensure an open airway by tilting the person's head back and lifting their chin.
- Pinch the person's nose closed with your hand.
- Take a normal breath and make a complete seal over the person's mouth.
- Deliver a breath that makes the chest rise visibly.
- Repeat this process, delivering two rescue breaths after every 30 compressions.

4. Compression-to-Ventilation Ratio:
The compression-to-ventilation ratio for CPR varies depending on the provider's training level and the circumstances. The most common ratio is 30 compressions to 2 rescue breaths for single-rescuer CPR. For two-rescuer CPR, the ratio is often 30 compressions to 2 rescue breaths as well, with a seamless transition between providers during compressions.

5. Use of Automated External Defibrillator (AED):
An automated external defibrillator (AED) is a device that delivers an electrical shock to the heart to restore its normal rhythm in cases of sudden cardiac arrest. If an AED is available, it should be used as soon as possible. The steps for using an AED generally involve:
- Powering on the AED and following the voice prompts or visual instructions.
- Placing the electrode pads on the person's bare chest as indicated by the AED's instructions.
- Clearing the area and ensuring no one is in contact with the person during the analysis and shock delivery.
- Following the AED's prompts for delivering a shock if advised.

6. Continuation of CPR:
CPR should be continued until one of the following occurs:
- The person starts to show signs of life, such as breathing normally, coughing, or moving.
- Trained medical personnel take over and direct you to stop.
- You are too exhausted to continue.

7. Transfer of Care:
Once medical personnel arrive, they will take over and provide advanced life support. It is crucial to give them a concise and accurate report of what has transpired, including the number of cycles of CPR performed, the use of an AED, and any other relevant information.


Performing CPR involves a series of critical steps aimed at sustaining vital organ function during emergencies. The primary objectives of CPR are to maintain blood flow and deliver oxygen to the body's vital organs until professional medical help arrives. MyCPR NOW recognizes the importance of CPR training and certification to equip individuals with the knowledge and skills necessary to respond effectively in emergency situations. Remember, early recognition, immediate activation of emergency services, and prompt initiation of CPR can significantly increase the chances of a positive outcome for someone in cardiac arrest.

CPR Certification
Back to blog