This cheat sheet explains the C-A-B order for CPR, which stands for Compressions, Airway, and Breathing. Students need this reference because CPR steps must be fast, clear, and easy to remember during an emergency. The C-A-B memory aid helps responders focus first on keeping blood moving to the brain and heart.
It is a study guide, not a replacement for certified CPR training.
Key Facts
- The CPR order C-A-B means Compressions first, then Airway, then Breathing.
- Check the scene for safety, check responsiveness, and call 911 or tell someone specific to call before starting CPR.
- For adult and teen CPR, push hard and fast in the center of the chest at a rate of 100 to 120 compressions per minute.
- A common CPR cycle is 30 chest compressions followed by 2 rescue breaths if you are trained and willing to give breaths.
- Chest compressions should be about 2 inches deep for an adult while allowing the chest to fully recoil after each push.
- Open the airway with the head-tilt, chin-lift method unless you suspect a serious neck or spine injury.
- Use an AED as soon as it is available, follow its voice prompts, and make sure no one touches the person during analysis or shock.
- Continue CPR until the person breathes normally, an AED or trained responder takes over, the scene becomes unsafe, or you are too exhausted to continue.
Vocabulary
- CPR
- CPR, or cardiopulmonary resuscitation, is an emergency procedure that uses chest compressions and sometimes rescue breaths to help circulate blood and oxygen.
- C-A-B
- C-A-B is the CPR memory aid for Compressions, Airway, and Breathing in that order.
- Chest compression
- A chest compression is a firm push on the center of the chest that helps move blood through the body when the heart is not pumping normally.
- Airway
- The airway is the path that air travels through the mouth, nose, throat, and lungs.
- Rescue breath
- A rescue breath is a breath given to another person to help move oxygen into the lungs when they are not breathing normally.
- AED
- An AED, or automated external defibrillator, is a device that can check heart rhythm and deliver a shock if needed.
Common Mistakes to Avoid
- Starting with rescue breaths instead of compressions is wrong because C-A-B puts blood circulation first in most CPR situations.
- Pressing too slowly or too lightly is wrong because weak compressions may not move enough blood to the brain and heart.
- Leaning on the chest between compressions is wrong because the chest must fully recoil so the heart can refill with blood.
- Forgetting to call 911 or send someone for help is wrong because CPR is a bridge until emergency responders and an AED arrive.
- Stopping compressions for long pauses is wrong because interruptions reduce blood flow and make CPR less effective.
Practice Questions
- 1 A student finds an unresponsive teen who is not breathing normally. List the first three actions the student should take before or as CPR begins.
- 2 If CPR compressions are done at 110 compressions per minute, about how many compressions should be completed in 2 minutes?
- 3 Using the 30:2 CPR cycle, how many rescue breaths are given after 90 chest compressions if the rescuer is trained and willing to give breaths?
- 4 Explain why the C-A-B order begins with chest compressions instead of checking the airway or giving breaths first.
Understanding Order of CPR steps (C-A-B) Memory Aid
CPR works by doing part of the heart’s job from outside the body. Each downward push raises pressure inside the chest. That pressure moves a small amount of blood through the heart, toward the brain, and around the body.
The amount is far less than a normally beating heart provides. Even so, it can protect important organs for a short time. This is why steady, well formed compressions matter more than many people expect.
Long pauses cause blood pressure to fall quickly. Once compressions restart, several more pushes are needed to build that pressure again.
Good technique depends on body position and control. A responder places the heel of one hand on the center of the chest, puts the other hand on top, and keeps the arms straight. The shoulders stay above the hands so body weight, not just arm strength, provides the push.
The chest must rise fully between pushes. Full recoil lets the heart refill with blood before the next push. Leaning on the chest prevents this refill.
Shallow pushes, slow pushes, and frequent stops all reduce the blood flow that CPR can create. Counting out loud can help a responder keep a steady rhythm and avoid losing track.
Breathing checks can be confusing in a real emergency. A person in cardiac arrest may make occasional gasps, snorts, or irregular movements of the chest. These are not normal breaths.
They can happen because the brain is not getting enough oxygen. A student should learn to recognize that normal breathing is regular and effective, not rare or strained. Rescue breaths have a purpose because they add oxygen to the lungs.
They should make the chest visibly rise. Blowing too hard or too fast can force air into the stomach, which may cause vomiting. If a breath does not make the chest rise, the airway may need to be repositioned before another attempt.
An AED is designed to examine the heart’s electrical activity and decide whether a shock could help. It does not shock every person. Some cardiac arrests involve a chaotic rhythm that may be reset by a shock.
Others do not. The machine gives instructions because correct timing and safety are essential. Everyone must be clear of the person while the AED checks the rhythm or delivers a shock.
Water, medication patches, and a very hairy chest can affect pad placement or contact, so trained practice is useful. In school, sports, workplaces, and public buildings, students can notice where AEDs are kept. Formal CPR training gives practice with manikins, emergency communication, teamwork, and the calm habits needed when a real person needs help.