artificial life support

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.

life-support Given that the heart is beating, and that metabolic processes in the body organs and tissues are intact, continuation of life depends on there also being effective exchanges with the external world: breathing, food and water intake, and output of waste. Damage may necessitate artificial take-over of one or more of these functions. Such take-over has become possible by virtue of medical technology.

‘Life-support’ describes any continuing medical treatment necessary for survival, as distinct from the short-term interventions involved in resuscitation, which are life-saving rather than life-sustaining. Very often, however, such life-sustaining measures become necessary after the initial success of a life-saving intervention.

The commonest forms of life-support are mechanical artificial ventilation and artificial feeding through a stomach tube. Such support may be required only for a period of weeks or months until recovery of the lost function occurs, but continued survival for some patients depends on permanent life-support. In that event the patient usually remains in hospital, but sometimes arrangements can be made to manage permanent life-support systems at home. Long-term dialysis for kidney failure is another form of life-support.

Sometimes a decision is made to discontinue life-support and let the patient die. This is most often in the first few days after resuscitation, when it becomes clear that there is no prospect of survival and that treatment is futile because it is merely prolonging the process of dying. Occasionally life-support is withdrawn after months or years, as when a patient on dialysis who develops new complications requests its withdrawal, or when a brain-damaged patient is diagnosed as in a permanent vegetative state and it is decided to stop tube feeding.

Bryan Jennett