How do I know if the treatment is no longer "of benefit?"

In some cases, the treatment may be "futile" ; that is, it may no longer fulfill any of the goals of medicine. In general, these goals are to cure if possible, or to palliate symptoms, prevent disease or disease complications, or improve functional status. For example, patients with severe head trauma judged to have no chance for recovery of brain function can no longer benefit from being maintained on a mechanical ventilator. All that continuation would achieve in such a case is maintenance of biologic function. In such a case, it would be justifiable to withdraw mechanical ventilation.