You mean, a sudden cardiac event, right?
The range of events for which CPR has even a vanishingly small chance of success is very narrow.
The range of events for which CPR is currently applied is enormous.
Take, for example, the patient found dead in bed at 5am nurse rounds. I have never, in 35 years, seen such a patient successfully resuscitated. Have you?
Have you ever seen one such patient without a preexisting DNR order NOT get CPR?
CPR is subject to more magical thinking than any other medical procedure of which I am aware.
Non-medical people are not expected to make decisions about when to administer CPR and when not to.
If a lay person comes across someone who is unconscious, and it is determined there is no heartbeat and breathing, you administer CPR. The chances may indeed be small across the vast range of reasons a person might be found with no pulse or breathing, but do you want to advocate that a 13 year old Boy Scout who has had training in CPR try to determine if it is worthwhile or not?
I would hope not. You would want that boy to do what he was trained to do, as a bridge to letting a professional decide.
I’ve got one report in the Jewish Observer (1990s, don’t
have cite handy) about how a no-code was averting when
the patient’s wife forcefully told the medical staff her
husband did *NOT* have a DNR. She was there, heard them
tell each other no code was necessary. I know another woman
whose father died bc of a “slow code”. So I do not believe
everyone without DNR escapes CPR, however futile it may
seem. BTW the first man lived for some months to see some
family events (but I can’t recall which)