So it depends on the setting and patient. Kids tend to have respiratory causes of cardiac arrest so the focus is more on airway management and positive pressure ventilation. Kids don’t generally code just out of nowhere like say a 90 year old might keel over. There’s usually a specific cause and if you can correct that cause they will rebound.

As for adults it’s about the setting. Outside of the hospital we should be teaching cpr only. Especially for lay people. It gets too complicated and they’re too stressed out to remember 30 and 2, 15 and 2. Plus most people have a reserve of air in their airway and lungs that gets circulated with compressions so focusing too much on trying to get breaths in causes too many delays and confusion.

Now for ems you can debate whether they should do cpr only with a non rebreather, a bls airway and bagging, a biad, or a definitive airway. It hugely depends on your protocols, provider availability, and who the patient is.

In hospital we are almost always going to secure the airway during a code to remove that from the equation. We have the resources and it can be done relatively quickly without the need to delay cpr for more than a pulse check in many cases.