The National Catholic Bioethics Center offers a helpful guide to Catholic teaching on medical ethics and how it applies to decisions for a patient in danger of death. It mentions some of the main points that should be included in a morally sound "Advance Directive" document to regulate medical decisions in case a patient is incapacitated.
That is a great document and thanks for sharing it. The Power of Attorney is becoming more important because doctors are afraid to share with even spouses medical information. I know some pro-life attorneys urging people to give someone this authority because if you can't make a decision, you need to make sure that someone who cares about you can.