CNN Health has an article which originated in Chicago, IL, from meetings of "a task force whose members come from prestigious universities, medical groups, the military and government agencies. They include the Department of Homeland Security, the Centers for Disease Control and Prevention and the Department of Health and Human Services." The results were a set of proposed guidelines in which doctors and medical personnel make "God-like" decisions regarding which patients are treated in case of a wide spread health care disaster. The report states:
To prepare, hospitals should designate a triage team with the Godlike task of deciding who will and who won't get lifesaving care, the task force wrote. Those out of luck are the people at high risk of death and a slim chance of long-term survival. But the recommendations get much more specific, and include:
• People older than 85.
• Those with severe trauma, which could include critical injuries from car crashes and shootings.
• Severely burned patients older than 60.
• Those with severe mental impairment, which could include advanced Alzheimer's disease.
• Those with a severe chronic disease, such as advanced heart failure, lung disease or poorly controlled diabetes.
I'm going to go out on a limb and suggest that there were no Roman Catholics at those meetings. An article on End-of-Life-Ethics states:
The Scriptures provide a sound foundation and a sure direction in helping us to respond to end-of-life questions by offering three major points: 1) life is a basic, but not absolute, good; 2) we are to be stewards of life, but we don’t have complete control and 3) we understand death in the context of belief in new life.
The National Catholic Bioethics Center has a publication "A Catholic Guide to End-of-Life Decisions An Explanation of Church Teaching on Advance Directives, Euthanasia, and Physician Assisted Suicide" available for purchase. And Eternal Word Television Network has an article on End-of-Life Decisions which states:
The natural law and the Fifth Commandment requires that all ordinary means be used to preserve life, such as food, water, exercise, and medical care. Since the middle ages, however, Catholic theologians have recognized that human beings are not morally obligated to undergo every possible medical treatment to save their lives. Treatments that are unduly burdensome or sorrowful, such as amputation, or beyond the economic means of the person, or which only prolong the suffering of a dying person, are morally extraordinary, meaning they are not obligatory.
Whether you are Roman Catholic or not, you might want to read their point of view before writing your own living will. Just Google "living will form" for information on free forms.