CPR Guidelines Explained: Why CAB Comes Before ABC
For many years, people learning cardiopulmonary resuscitation (CPR) were taught to remember the ABCs: Airway, Breathing, and Chest Compressions. However, updated research led the American Heart Association (AHA) to revise these steps to CAB — Chest Compressions, Airway, Breathing.
This change reflects a better understanding of how CPR saves lives during sudden cardiac arrest.
Why Chest Compressions Come First
When cardiac arrest occurs, the heart stops pumping blood effectively. Although breathing may also stop, oxygen often remains in the blood and lungs for the first few minutes.
Starting CPR with chest compressions helps:
- Circulate existing oxygenated blood to the brain and heart
- Reduce delays in restoring blood flow
- Improve survival outcomes
Under the old ABC method, valuable time could be lost while opening the airway and delivering breaths before compressions began. In an emergency, those seconds matter.
CAB Makes CPR Easier for Bystanders
Another benefit of the CAB approach is that it encourages more people to act. Many bystanders hesitate to perform mouth-to-mouth breathing, especially without training. Chest-compression-only CPR allows untrained individuals to still provide life-saving care until help arrives.
That said, formal CPR training remains essential for learning proper technique, breathing, and AED use.
How CPR Is Performed Using CAB Guidelines
First aid and CPR courses teach these steps in detail. At a high level, the CAB approach includes:
1. Call for Emergency Help
- Call 911 immediately or direct someone nearby to do so
- If alone, shout for help while beginning care
2. Check Responsiveness
- Tap the person and shout
- If there is no response, place the person flat on their back
3. Begin Chest Compressions
- Place the heel of one hand in the center of the chest
- Place the other hand on top and interlace fingers
- Push hard and fast
4. Compression Depth and Rate
- Adults and children: compress at least 2 inches
- Infants: compress about 1.5 inches
- Aim for 100–120 compressions per minute
A common rhythm reference taught in CPR courses is the beat of “Stayin’ Alive.”
5. Add Breaths (If Trained)
- Open the airway using a head-tilt, chin-lift
- Pinch the nose and give two breaths after every 30 compressions
- Continue cycles until emergency services arrive
Untrained rescuers should continue hands-only chest compressions.
Why CPR Training Is Essential
Sudden cardiac arrest claims thousands of lives each year. While updated guidelines have improved outcomes, proper CPR technique requires hands-on training.
CPR courses teach participants how to:
- Perform effective chest compressions
- Provide rescue breaths safely
- Use an AED correctly
- Stay calm and act quickly during emergencies
At Hamilton First Aid, our CPR courses follow current guidelines and focus on real-world confidence and skill development.
Learn CPR — It Saves Lives
Knowing CPR is a skill everyone should have. Whether at home, at work, or in public, the ability to respond during cardiac arrest can mean the difference between life and death. Updated CPR guidelines make it easier than ever to act — but training ensures you do it correctly.