I'd never forgive myself if I didn't try.
That's precisely the way I feel.
As do I.
I would assume most in health care would agree.
I've lost track, but somewhere between 5-10 saves in around 100 arrests. Most were witnessed, in-hospital arrests. In the field, maybe 2.
As for how long you can do CPR, it too varies. One person performing solo, I would assume short times- probably because you get so winded. But I've personally done compressions over 30 minutes. Can't comment on the quality of them towards the end, and it is quite a workout!