As the term implies, an advance directive is a set of instructions or guidelines made in advanced by a competent person specifying his/her medical care when he or she becomes physically and mentally incapacitated.
It is not legally required to complete an advance directive. However, if a person has not expressed his/her wishes at end-of-life, other people, like a court-appointed guardian, a close family member or a friend will make the decision on the person’s behalf in an event that he/she is incapacitated or permanently unconscious.
A competent person is one who can make an informed decision. A person must have the ability to understand the nature, extent, probable consequence of a medical procedure or recommendation. A person is also able to make an evaluation of the risks and benefits of a proposed medical intervention and weigh them against alternative options. A competent person is also able to communicate an understanding of directives.
The two main parts of an advance directive are living will and surrogate directive.
The two main parts of an advance directive are A) living will (also known as treatment directive) and B) surrogate directive (also known as proxy directive, or power of attorney for healthcare).
A living will is a set of instructions of medical care at the end of life.
The living will is a document that usually refuses treatment including life-sustaining treatments, interventions and the provision of artificial nutrition and hydration towards the end of life. Although most living wills state limitations of treatment or intentions of forgoing life-sustaining treatments, this is not always the case. A directive can also request aggressive treatments. A patient has the choice to indicate in their living will that they want such treatment.
A living will cannot be used to demand something illegal or immoral.
A living will cannot be used to ask for something illegal or immoral, such as ending one’s life or demanding for any kind of treatments or interventions. Healthcare providers decide appropriate treatments and interventions. They cannot just administer them because of patient’s or family’s demand.
The Ethical and Religious Directives for Catholic Health Care Services, a document developed by the United States Conference of Catholic Bishops (USCCB) that provides moral guidance to Catholic healthcare institutions, states that the Church is committed to moral medical practice and “will not honor an advance directive that is contrary to Catholic teaching. If the advance directive conflicts with Catholic teaching, an explanation should be provided as to why the directive cannot be honored.”
In cases of moral conflicts, patients and family members must be provided with the opportunity for discharge in order to seek out another facility. Family members and surrogates must be informed of the decision in a timely manner
 Virginia Catholic Conference -Diocese of Arlington and Diocese of Arlington, Catholic Advance Medical Directives: Making Life Decisions, (Richmond, VA, December 2010), 4. Available at http://www.cdrcmfl.org/wp-content/uploads/2014/01/Advance-Medical-Directive.pdf,accessed on January 23, 2018.
 David F. Kelly. Medical Care at the End of Life: A Catholic Perspective (Washington DC: Georgetown University Press, 2007), 5.
 United States of Catholic Bishops (USCCB), Ethical and Religious Directives for Catholic Health Care Services Sixth Ed, (Washington, DC, 2018), No. 24.
Matthew P. Lomanno,”Healthcare Proxy and Advance Directives,” in Catholic Healthcare Ethics: A Manual for Practitioners, Second edition, edited by Edward J. Furton, Peter J. Cataldo and Albert Moraczewski, OP, 217. Philadelphia: The National Catholic Bioethics Center, 2009.