With the advances in medical technology people are now living much longer than previously. Sometimes this may involve prolonging a person's life when that person's decision-making capacity is impaired.
This means another person or authority may need make a decision about the person's medical treatment on their behalf, see: When someone 16 or over can't consent.
People may wish to have some say in what treatment they receive in these situations. A competent adult can make an advance care directive, appointing a subsitute decision-maker and outlining their wishes in advance of such situations. See: Advance Care Directives. Previously the Natural Death Act 1983 (SA) and the Guardianship and Administration Act 1993 (SA) enabled a person to complete a form similar to an advance care directive. See Advance care directives before July 2014.
Section 17(2) of the Consent to Medical Treatment and Palliative Care Act 1995 (SA) says that a medical practitioner responsible for the care of a patient in the terminal phase of a terminal illness is under no duty to use or continue to use life sustaining measures if the effect would be merely to prolong life in a persistent vegetative state or moribund state without any real prospect of recovery [s 17(2)(a)]. This is the case even if the patient or the patient's representative requests their use or continuation. However, if the patient or their representative requests that life sustaining measures be withdrawn, the medical practitioner must withdraw them [s 17(2)(b)].