in which a person, in case of incapacitation
, expresses in advance
his or her wishes concerning the use of medical measures to prolong life. Typically living wills are used to reject extraordinary measures, such as intravenous feeding and mechanical respirators, when death appears imminent. The use of living wills was affirmed by a 1990 U.S. Supreme Court
decision. Family members and medical personnel
sometimes challenge a living will because of unclear or legally invalid instructions, concern over possible legal consequences, or the emotional difficulty involved in withholding treatment.
A living will is similar to a DNR order, but the latter can be performed by one's family members once one is incapacitated.