Mrs. A is an 85-year-old woman living at home with her husband, who has moderately severe Alzheimer disease and for whom she provides daily care. She has an 8.5 cm abdominal aortic aneurysm. Three months ago she consulted a vascular surgeon, who recommended surgical repair of her aneurysm. However, another physician told Mrs. A that she “would never survive the operation.” Mrs. A decided to “take her chances” and refused surgery, primarily because of her wish to provide uninterrupted care for her husband; however, she agreed to discuss the decision further with the surgeon at a future visit. Before such a visit can take place, however, Mrs. A is taken to the emergency department after collapsing at home with abdominal pain. Physical examination reveals a systolic blood pressure of 50 mmHg and a tender pulsatile abdominal mass. Mrs. A is moaning and barely conscious. The surgeon diagnoses a ruptured aortic aneurysm and believes that Mrs. A will die without emergency surgery.

Mr. B is a 25-year-old man affected by extensive muscular atrophy resulting from Guillain–Barré syndrome. For two years he has been dependent on a ventilator and his prognosis indicates no chance of recovery. One day he announces that he wants the ventilator support withdrawn and that he be allowed to die because he considers his life intolerable. Those caring for him disagree with his decision and the reasons for it because he is not terminally ill and because others with his condition have meaningful and fulfilling lives.[…]