Living wills
In case you become terminally ill and cannot communicate what medical procedures and intervention you do or don't want, a living will communicates your wishes on your behalf. This document — also known as an advanced medical directive — gives medical personnel clear instructions as to what measures to take in keeping you alive.
This is different from a Medical Power of Attorney in that it only conveys your wishes if you are determined by your doctors to be terminally ill.
States often differ as to when a living will can go into effect, and in some cases the stipulations in your living will may be subject to interpretation. Regardless of these variations, a living will is probably the best way you can guide your care if you cannot communicate.