I understand where you're coming from. Each person has the right to life, liberty, and the pursuit of happiness and thus children must be ensured that legally until they are mature enough to do it for themselves (which is also the argument for allowing/banning abortion). I guess that the issue now becomes even if there is a general consensus, we still see a lot of these cases going before judges and ethics panels. Therefore, relating back to OP's scenario, would it all fall in place fast enough to save a minor in pediatric arrest? I don't think so.
As has been stated multiple times, and as per the American Academy of Pediatrics recommendations for dealing with that exact scenario, emergencies are treated differently by the law, courts, and anyone with common sense. In a life threatening time sensitive emergency nothing needs to be in place - you treat first, while in parallel obtaining LE/court assistance.