Explain why the american heart association changed the abcs of cpr to the cabs of cpr

The American heart association changed ABC (Airway, Breathing, Compressions) to CAB (Compressions, Airway, Breathing) because when the ABC sequence to perform CPR was performed, people would spend so much time trying to open the airway that there was a delay in chest compressions making rescue breathes harmful. With the new CAB sequence people initiate chest compressions sooner and ventilation is only slightly delayed.

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Your answer is  d.)relationship between pressure and air volume and led to the understanding of how respiration works