The National Hospice and Palliative Care Organization wrote in its 2005 pamphlet, "Questions and Answers: Advance Directive and End-of-Life Decisions":
"'Advance directive' is a general term that describes two types of legal documents:
Medical power of attorney
These documents allow you to instruct others about your future medical care wishes and appoint a person to make healthcare decisions if you are not able to speak for yourself...
Advance directives give you a voice in decisions about your medical treatment, even if you are unconscious or too ill to communicate...
Your advance directives become legally valid as soon as you sign them in front of the required witnesses. However, they normally do not go into effect unless you are unable to make your own decisions and each state establishes its own guidelines for when advance directives become operative. The rules may differ for living wills and medical powers of attorney..."
The American Bar Association explained in its website's section on "Law for Older Americans" (accessed Aug. 2, 2006):
"A health care advance directive is the primary legal tool for any health care decision made when you cannot speak for yourself. 'Health care advance directive' is the general term for any written statement you make while competent concerning your future health care wishes. Formal advance directives include the living will and the health care power of attorney."
The American Medical Association's Council on Ethical and Judicial Affairs, published a June, 1991 report entitled "Decisions to Forgo Life-Sustaining Treatment for Incompetent Patients," explaining that:
"An advance directive is a document that enables competent persons to exercise their right to direct medical treatments in the event that they lose their decision making capacity. There are two categories of advance directives: (1) a living will, which indicates the types of treatment that an individual wishes to receive or forgo under specified circumstances, and (2) a durable power of attorney for health care, which designates a proxy to make treatment decisions. There are a number of different advance directive forms currently available and many more are being developed. Some forms may combine a proxy designation with specific instructions for the proxy.
The obligation to respect a competent patient's right to self-determination includes the obligation to follow the instructions of an advance directive. An advance directive directly reflects the patient's values and preferences with regard to life-sustaining treatment."