When does CAB go in effect

Think of it this way: if you rescue breathe for someone, sure, you're getting some oxygen in the lungs. But if they have no circulation, it doesn't matter how perfect your rescue breathing is; that oxygen will never get to the cells that need it. That's part of the reason for the change to CAB over ABC, as well as the average time doing the "look, listen, feel" exceeding the recommended time. Time is of the essence in restoring oxygen supply to prevent further cell death.

A hint for prioritizing patients for NCLEX- it's not always about ABC/CAB. Sometimes, it's about what is different about the patient in this circumstance.