Often used synonymously with the term "ordinary/extraordinary means" since the two sets of terms were equated in the 1980 Vatican Declaration on Euthanasia. This principle constitutes an important approach to the analysis of ethical questions arising from the general obligation to preserve human life and the limits of that obligation. Among other questions, the principle addresses whether the forgoing of life-sustaining treatment constitutes euthanasia or physician-assisted suicide in certain circumstances and it guides individuals and surrogate decision-makers in the weighing of benefits and burdens.
As conceived in the Catholic moral tradition, the principle holds that one is obligated to preserve his or her own life by making use of ordinary means, but is under no obligation to use extraordinary means (see Ethical and Religious Directives, nn. 32, 56 and 57). In other words, when a medical intervention or "means" is proportionate, one has a general obligation--all things considered--to accept the treatment. When the medical intervention constitutes a disproportionate means, then one is no longer obliged to undergo the treatment. Since judgments that a given means is either proportionate or disproportionate must be made in light of the personal (including religious beliefs), familial, economic, and social circumstances of each individual patient, an a priori list of treatments that can be classified as always and everywhere proportionate or disproportionate is not possible.
Proportionate means is any treatment that, in the given circumstances and in the judgment of the patient or the patient’s surrogate, offers a reasonable hope of benefit and is not too burdensome for the patient or others. What is a reasonable hope of benefit to the patient should be judged within the context of the whole person (i.e., considered holistically, not just physiologically). Generally, a treatment or means is not too burdensome when it offers benefits that outweigh the burdens to the patient and others. These determinations should be patient specific and include considerations of the expected medical outcomes and the patient’s personal, financial, familial, and social circumstances.
A disproportionate means is any treatment that, in the given circumstances and in the judgment of the patient or the patient’s surrogate, either offers no reasonable hope of benefit (taking into account the well-being of the whole person) or is too burdensome for the patient or others, i.e., the burdens or risks are disproportionate to or outweigh the expected benefits of the treatment. Again, these determinations should be patient specific and take into consideration the patient’s personal, financial, familial, and social circumstances.
If one uses the terms ordinary and extraordinary means (as opposed to proportionate and disproportionate), care must be taken not to confuse the terms "ordinary care" and "ordinary means." While patients may forego treatments that are disproportionate or extraordinary means, there is always an obligation to provide ordinary care due to the sick person, that is, to provide non-medical nursing interventions. [See also: Lynn, J. and J. F. Childress, "Must Patient Always Be Given Food and Water?" The Hastings Center Report 13 (October 1983): 17-21; O’Rourke, K.D. and J. deBlois, "Removing Life Support: Motivations, Obligations," Health Progress 73 (July/August 1992): 20-7, 38.]