Last Updated On: October 7, 2024
Sudden cardiac arrest (SCA) is responsible for more than 50% of death related to cardiac health, which contributes to upto 20% of global mortality. In such emergencies, cardiopulmonary Resuscitation (CPR) can potentially save lives. However, the responders must stay aware of its guidelines, which have evolved over time.
Initially, CPR followed the A-B-C sequence (Airway, Breathing, Compressions), but studies showed that changing to the C-A-B sequence (Compressions, Airway, Breathing) improves survival rates. This shift prioritizes chest compressions, which are critical in maintaining blood flow to vital organs until professional help arrives.
Read on to learn more about the shift in CPR steps A-B-C to C-A-B and its significance.
For years, the A-B-C method was the standard sequence taught for CPR. This approach emphasized checking the airway first, followed by rescue breaths and chest compressions.
The first step was ensuring the patient’s airway was clear. This involved tilting the head back and lifting the chin to open the airway, often a necessary procedure if the person was unconscious and their airway was blocked by the tongue or other obstructions.
Once the airway was cleared, two rescue breaths were administered, ensuring oxygen entered the patient’s lungs. This step focused on reviving the respiratory system before addressing the heart’s function.
Only after addressing the airway and breathing did chest compressions begin. The compressions were applied to the chest to help circulate blood through the heart and into vital organs like the brain and lungs.
While the A-B-C method seemed logical, it had several limitations when used in real-world emergencies. These shortcomings led to CPR sequence changes.
One of the biggest limitations of the A-B-C approach was the delay in starting chest compressions. When someone suffers from cardiac arrest, every second without circulation increases the risk of brain damage and death. The time spent checking the airway and delivering breaths often delayed the most critical intervention: chest compressions.
For bystanders without CPR training, remembering the steps of A-B-C and executing them properly was often difficult. Studies showed that even those trained in A-B-C sometimes struggled under pressure to perform the sequence correctly, leading to hesitation or incomplete CPR efforts.
Research has indicated that in the initial minutes of cardiac arrest, oxygen levels in the blood remain relatively high. Therefore, focusing on compressions to maintain blood circulation is more crucial than attempting to restore breathing immediately. This realization led to the introduction of the C-A-B sequence, which places compressions before breathing.
The move from A-B-C to C-A-B represents a fundamental shift in the approach to CPR. Introduced in 2010, this change is based on the understanding that compressions before breaths are the most critical component of CPR, especially in the first few minutes of cardiac arrest.
Chest compressions before breaths can provide enough oxygenated blood to the brain and heart even without immediate rescue breaths. In a typical out-of-hospital cardiac arrest, the victim often has enough oxygen in their bloodstream to support the brain and heart for a few minutes—provided compressions start immediately. In the new C-A-B approach, the following steps should be taken:
This sequence ensures that blood circulation is the top priority, which significantly reduces the chances of brain damage or death while waiting for emergency services.
To fully appreciate the benefits of the C-A-B approach, people learn by breaking down its individual components and understand how each works together in a cardiac emergency.
In CPR, chest compressions are responsible for keeping the heart pumping and moving oxygenated blood to the brain and vital organs. To perform compressions effectively:
Once compressions are underway, the next step is to open the airway to ensure air can enter the lungs. The head-tilt, chin-lift method is still the most effective way to do this, which allows air to flow freely when breaths are given.
Once the airway is open, give two rescue breaths, each lasting about one second. Ensure the chest rises with each breath, indicating that the air is entering the lungs. After delivering two breaths, immediately return to chest compressions. The cycle of 30 compressions followed by two breaths should continue until emergency medical services (EMS) take over or the person regains consciousness.
When confronted with a cardiac arrest situation, performing CPR using the C-A-B method can save lives. The bystanders should follow these CPR steps A-B-C to C-A-B:
The importance of calling emergency services can be understood by the fact that even slight delays in immediate help can cost a life. Thus, lay responders should always start by calling emergency services or directing someone nearby to do so. The sooner professional help arrives, the better the chances of survival.
Place the victim on a firm surface and immediately begin chest compressions. Press hard and fast in the center of the chest, maintaining a rate of 100-120 compressions per minute. Don’t worry about being perfect—doing something is always better than doing nothing.
Once you’ve established a rhythm of compressions, open the airway using the head-tilt, chin-lift maneuver to ensure airflow.
With the airway open, pinch the nose shut and cover the person’s mouth with yours. Deliver two slow, steady breaths, ensuring the chest rises with each one. Resume chest compressions immediately after the two breaths.
Repeat the cycle of 30 compressions followed by two breaths until EMS arrives or the patient shows signs of life, such as breathing or movement. If an Automated External Defibrillator (AED) is available, use it as soon as possible, according to the device’s instructions.
The change from CPR steps A-B-C to C-A-B has proven to be more effective, especially for laypeople and bystanders who may be performing it for the first time. Here are some key benefits of the updated sequence:
The shift from CPR steps A-B-C to C-A-B represents an essential evolution in this life-saving practice. This emphasizes the critical role that chest compressions play in saving lives during cardiac arrest. Whether you’re a trained professional or a bystander, knowing and using the updated C-A-B method can make a difference in emergencies.
The more people come to know the guidelines with proper training and implement them, the higher the survival rates from cardiac arrest, and this will provide a better chance of recovery for the victim.
