Today we completed an EFR course - Emergency First Response. This is a jazzed up (or dumbed down, depending on your viewpoint) first aid qualification, designed by PADI primarily to be able to do their own first aid courses which form a prerequisite for certain dive qualifications. We intend to take the Rescue Diver course whilst we're out in Sweden for six months.
I've done first aid courses before, notably through my 'military' service many, many years ago. Just like with any other skill you don't maintain or use, it fades quickly. CPR has been simplified a lot from back in those days. Many people, even those who are trained to give CPR, frequently hesitate in a sharp situation, afraid that they will not get it right and make the situation worse, rather than better. Our instructor reinforced the point that if someone's suffering a cardiac arrest, they're tecnically dead, or 'in the worst possible state of health'. Whatever you do, you can only make the situation better. You can't be deader than dead. Imperfect CPR is infinitely better than perfect CPR witheld.