You've got to get your beliefs, preferences and directives in writing, AND! AND! AND! you've got to have somebody --- your spouse, your oldest child, your brother or whoever --- who really understands what you want, to be there to advocate for you. As important as a document is, a document won't speak up for you and bang its fist on the Clinical Manager's desk when there's a dang medical ethicist saying your life is meaningless, and a hospital administrator who wants to free up a bed.
My personal recommendation is to go HERE and click on your state and evaluate for yourself what you want when you're too weak to be as communicative or as assertive-as-you-wanna-be.
Get it in writing, and let your nearest and dearest know.
Very good advice Mrs. D. I know who will get my medical proxy, a very good friend who truly embodies the American value of “I might not agree with what you say, but I will defend to the death your right to say it”.
She understands me and would never, in a thousand years, substitute her own judgement for what, in her best understanding, would be mine.
And, she’d be more than willing to pound on a desk if necessary, and sadly it often is.