I don't know of anything you can take.
But in the US, you can sign a Do-not-resuscitate (DNR) order. If you're young and otherwise healthy, the doctors will try to talk you out of it, but it's your choice and you can tell them you don't want to end up with permanent damage. Or sign one before going to the hospital and just say these are your wishes.
It's a brilliant place to ctb, but also probably the hardest for all the reasons listed in previous posts.