Medical Futility: The absence of a useful purpose or useful result in a diagnostic procedure or therapeutic intervention. The situation of a patient whose condition will not be improved by treatment or instances in which treatment preserves permanent unconsciousness or cannot end dependence on intensive medical care. (From Ann Intern Med 1990 Jun 15;112(12):949)Withholding Treatment: Withholding or withdrawal of a particular treatment or treatments, often (but not necessarily) life-prolonging treatment, from a patient or from a research subject as part of a research protocol. The concept is differentiated from REFUSAL TO TREAT, where the emphasis is on the health professional's or health facility's refusal to treat a patient or group of patients when the patient or the patient's representative requests treatment. Withholding of life-prolonging treatment is usually indexed only with EUTHANASIA, PASSIVE, unless the distinction between withholding and withdrawing treatment, or the issue of withholding palliative rather than curative treatment, is discussed.Refusal to Treat: Refusal of the health professional to initiate or continue treatment of a patient or group of patients. The refusal can be based on any reason. The concept is differentiated from PATIENT REFUSAL OF TREATMENT see TREATMENT REFUSAL which originates with the patient and not the health professional.Dissent and Disputes: Differences of opinion or disagreements that may arise, for example, between health professionals and patients or their families, or against a political regime.Ethicists: Persons trained in philosophical or theological ethics who work in clinical, research, public policy, or other settings where they bring their expertise to bear on the analysis of ethical dilemmas in policies or cases. (Bioethics Thesaurus)Persistent Vegetative State: Vegetative state refers to the neurocognitive status of individuals with severe brain damage, in whom physiologic functions (sleep-wake cycles, autonomic control, and breathing) persist, but awareness (including all cognitive function and emotion) is abolished.Secularism: Indifference to, or rejection of, RELIGION or religious considerations. (From Merriam-Webster's Collegiate Dictionary, 10th ed)Life Support Care: Care provided patients requiring extraordinary therapeutic measures in order to sustain and prolong life.Ethics, Medical: The principles of professional conduct concerning the rights and duties of the physician, relations with patients and fellow practitioners, as well as actions of the physician in patient care and interpersonal relations with patient families.Personal Autonomy: Self-directing freedom and especially moral independence. An ethical principle holds that the autonomy of persons ought to be respected. (Bioethics Thesaurus)Early Termination of Clinical Trials: Earlier than planned termination of clinical trials.Euthanasia, Passive: Failing to prevent death from natural causes, for reasons of mercy by the withdrawal or withholding of life-prolonging treatment.Decision Making: The process of making a selective intellectual judgment when presented with several complex alternatives consisting of several variables, and usually defining a course of action or an idea.Ethics, Nursing: The principles of proper professional conduct concerning the rights and duties of nurses themselves, their patients, and their fellow practitioners, as well as their actions in the care of patients and in relations with their families.