The Basic Principles of CPR: A Comprehensive Guide

CPR: Step-by-Step

Mastering the Lifesaving Essentials

Cardiopulmonary Resuscitation (CPR) is a crucial lifesaving technique that significantly increases the survival rate of individuals experiencing sudden cardiac arrest. This comprehensive guide delves into the fundamental principles of CPR, equipping you with the necessary knowledge and confidence to perform CPR effectively in emergencies.

1. Early Recognition and Activation

Understanding the initial signs and promptly responding to a cardiac emergency are critical.

Assess the Situation

  • Responsiveness: Gently shake the victim’s shoulders and ask loudly, “Are you okay?” to check responsiveness.

  • Assess Breathing: After confirming unresponsiveness, check for normal breathing by looking for chest movement, listening for breath sounds, and feeling for exhaled air. Agonal breathing, which may appear as gasping, should not be considered effective breathing.

Call for Help

  • Immediate Action: If alone, shout for nearby help before starting CPR to ensure emergency services are alerted as soon as possible. If someone is nearby, instruct them to call 911 and find an AED while you begin CPR.

2. Check for Breathing

Proper assessment of the victim's breathing status is crucial for determining the next steps.

Open the Airway

  • Head-Tilt, Chin-Lift Maneuver: Place one hand on the forehead and the other on the chin, then gently tilt the head back and lift the chin up. This maneuver helps clear the air passage by lifting the tongue away from the back of the throat.

Look, Listen, and Feel

Duration: Spend no more than 10 seconds determining if the person is breathing adequately by looking for chest movement, listening at the mouth for breathing sounds, and feeling for air flow on your cheek.

3. Begin Chest Compressions

Effective chest compressions circulate blood to vital organs, providing a lifeline until advanced care arrives.

It is crucial to perform chest compressions as part of CPR to ensure blood flow to the heart and brain.

Hand Placement

  • Correct Positioning: Locate the center of the chest between the nipples and place the heel of your hand on the lower half of the sternum.

Compression Depth

  • Force and Depth: Compress the chest at least 2 inches for adults, and about 1.5 inches for children. Ensure each compression is hard and fast, with complete chest recoil between compressions to allow the heart to refill with blood.

4. Deliver Rescue Breaths

Providing oxygen to the victim's lungs is crucial for maintaining oxygen levels in the blood.

Seal the Airway

Mouth-to-Mouth: Before sealing the airway, ensure the person's mouth is clear of obstructions. Then, ensure a tight seal over the victim’s mouth with yours, pinch the nose shut, and deliver two rescue breaths.

Watch for Chest Rise

  • Effective Breaths: Each breath should last about one second and make the chest visibly rise. Avoid quick or forceful breaths to prevent air from entering the stomach.

5. Continue Compressions and Breaths

Maintain a rhythm to maximize blood flow and oxygen delivery until professional help arrives. Be aware that hyperventilation-induced hypotension can occur during CPR, potentially impacting the quality of resuscitation efforts in both in-hospital and out-of-hospital settings.


  • Duration and Sequence: Continue with cycles of 30 compressions and 2 breaths. Do not stop CPR until professional help takes over, the victim starts breathing normally, or you are too exhausted to continue.

6. CPR Ratio and Rate

Consistency in CPR performance is key for its effectiveness.

Compression Rate

  • Speed: Aim to deliver 100-120 compressions per minute. Keep a steady pace, using the beat of a familiar song like "Stayin' Alive" by the Bee Gees to maintain rhythm.

Compression-to-Breath Ratio

  • Consistency Across Ages: Maintain a compression-to-breath ratio of 30:2 for adults, children, and infants when alone. When two rescuers are available for an infant, use a ratio of 15:2.

7. Compression Technique

Optimal technique ensures maximum effectiveness of each compression.

Effective Compressions

  • Using Body Weight: Lean directly over the chest and use your body weight to help compress the chest, keeping your arms straight.

Minimize Interruptions

  • Continuous Flow: Strive to keep interruptions to less than 10 seconds during transitions between compression cycles and rescue breaths.

8. Use of Automated External Defibrillator (AED)

An AED can be a critical tool in cardiac emergencies, providing an electric shock to help the heart re-establish an effective rhythm. Early defibrillation is crucial in treating ventricular fibrillation, a common cause of sudden cardiac death.

Prompt Use

  • Integration with CPR: As soon as an AED is available, pause CPR, turn on the AED, and apply the pads as directed. Follow the AED's prompts, and resume CPR immediately after the shock is delivered, if instructed, or continue following the AED’s prompts.

Pad Placement

  • Proper Placement: Place one pad on the upper right chest and the other below the left breast to ensure effective delivery of the shock.

9. Special Considerations

Different scenarios may require slight modifications in the CPR technique.

It is also important to understand the principles of resuscitation in the context of in-hospital cardiac arrest.

Infant CPR

  • Technique: Use two fingers in the center of the chest just below the nipple line for compressions. Use a two-thumb encircling hands technique if two rescuers are available.

Pregnant Women

  • Modification for Comfort: If possible, perform compressions with the woman slightly tilted to her left to avoid compression of the vena cava.

10. Emotional Preparedness

Handling a CPR situation requires both physical and mental readiness.

Stay Calm

  • Mental Focus: Maintaining calm helps you perform CPR more effectively and reassures the victim, if they are conscious.

Follow Instructions

  • Clear Communication: If other bystanders are present, clearly communicate who should call 911, who should fetch the AED, and who should assist in the CPR process if needed.


Mastering the basic principles of CPR empowers you to act effectively in emergency situations. Familiarizing yourself with these steps and regularly refreshing your skills through training and practice can make a critical difference, potentially saving a life. Remember, your actions can provide a vital bridge of care that sustains a person until professional medical help arrives.

Save a Life Get CPR Certified today!

Back to blog