What is the initial step of the C-A-B sequence in CPR?

The correct initial step of the C-A-B sequence in CPR is chest compression. This step emphasizes the importance of providing effective and immediate chest compressions to initiate blood circulation in a cardiac arrest scenario. The focus on chest compressions first is based on the understanding that, in a situation where the heart has stopped pumping blood, the priority is to restore blood flow to vital organs, especially the brain.

Chest compressions should be performed at a depth of approximately 2 to 2.4 inches for adults, at a rate of 100 to 120 compressions per minute. This method allows for the best chance of survival by maintaining blood flow to the heart and brain until advanced medical help can arrive or until the heart rhythm can be restored.

Other steps in the C-A-B sequence, such as assessing airway and breathing, or defibrillation, come after ensuring that effective chest compressions are initiated. The change to C-A-B instead of the previous A-B-C sequence reflects updated guidelines that prioritize circulation first, improving outcomes in cases of cardiac arrest.