artificial life support, systems that use medical technology to aid, support, or replace a vital function of the body that has been seriously damaged. Such techniques include artificial pacemakers, internal defibrillators, dialysis machines (see kidney, artificial), and respirators. The use of life-support systems to prolong the life of a patient who has suffered apparently irreversible damage to a vital organ system may raise such ethical issues as the quality of life, euthanasia, and the right to die, and has been the subject of much legal and moral debate. Some people specify their wishes concerning prolonged artificial life support, especially should they be in a persistent vegetative state (see coma), in a living will. A health-care proxy is another legal means of insuring that a person's wishes regarding artificial life support are respected, even if the person is unable to communicate those wishes.