I follow reported health news. My understanding is that if you have a transient event (hypothermia, drowning, electrical shock, internal ticking problem), and

I follow reported health news. My understanding is that if you have a transient event (hypothermia, drowning, electrical shock, internal ticking problem), and you're otherwise healthy, CPR is helpful. But if you have a chronic heart condition, CPR is not going to fix that. Additionally, if you're old, several of your ribs will be cracked, possibly a lung will be punctured, and then during surgery they will crack the rest. So it's unlikely you'll ever walk out of the hospital. Meth overdose is a weird one. According to one video I saw on Youtube, you need CPR every 5 minutes or so as they take you to the hospital after they inject you with an antidote. So when revived meth patients try walking away from EMS, the ambulance just follows them until they fall over again. Anyway, I'm just trying to illustrate how CPR is a complex thing, and you should do your own research to understand it better.