Terri Schiavo, a Florida patient who existed for the last 15 years in a “persistent vegetative state (PVS)” died last Thursday. In 1990 a “chemical imbalance,” brought on by an eating disorder caused her heart to stop beating and subsequently cut off oxygen to her brain.

A “persistent vegetative state” is a term of consensus, not unanimity, among neurologists. Consensus also marks the following medical judgments or assessments relating to the condition A person in PVS is capable of a reflexive response to a stimulus—but is unaware. PVS is not a state of coma which is a state of unconsciousness and inability to be aroused.

People in PVS are not brain dead, but feel neither hunger, thirst nor pain. They can breathe without a respirator and their open eyes can appear to track a moving object—as Schiavo did, to the great surprise of onlookers. A vegetative state caused by lack of blood or oxygen delivery to the brain, which has gone on more than five years is considered permanent.

Over the same 15-year period a fierce legal battle over whether to sustain or withdraw (or reinsert) the tube that provides Schiavo with nutrition and hydration (“food and water”) divided her parents and her estranged husband. The legal battle was all but over, in the husband’s favour (against re-inserting) just before she died, but the ethical divide, not just in the Schiavo household but in the wider society, remains as wide and unrelenting as ever.

How is the ethical obligation to treat patients like Schiavo described?

In the case of both competent and incompetent patients, whether medical treatment is ethically obligatory, non-obligatory, or optional, depends on a calculus of benefits and burdens. If the benefits outweigh the burdens, the basic medical obligation always to heal, not to harm, is obviously operational. If no reasonable hope of benefit exists, all expense, pain, or other inconvenience becomes excessive, and there is no obligation to treat. If a reasonable hope of benefit exists, along with significant burdensomeness, treatment is optional.

Competent patients, of course, retain the right to make decisions for themselves about treatment in the light of their own assessments of burdens and benefits.

Application of these distinctions to Schiavo presumes that medically-administered nutrition and hydration is a form of medical treatment. This is the view of some professional codes, philosophical arguments, and the US Supreme Court, but not everyone, including Schiavo’s parents agrees. They regard it as nonmedical sustenance, which imposes a standard human obligation. On this understanding, withholding nutrition and hydration amounts to starvation.

As the late English philosopher GEM Anscombe once bluntly put it: “For willful starvation there can be no excuse. The same can’t be said quite without qualification about failing to operate or to adopt some course of treatment.”

C Everett Koop, a former US Surgeon General, similarly views withholding nutrition and hydration as an intentional act of killing that amounts to active euthanasia, because it causes a preventable death.

Advocates of nutrition and hydration as sustenance argue on three fronts. First, they claim that the provision is required because it is necessary for the patient’s comfort and dignity.

Secondly, there’s the matter of the procedure’s symbolic significance. Feeding the hungry is a response to a fundamental human claim, and a clear symbol that human life is inescapably social. We are our brothers’ and sisters’ keepers, especially when they are incompetent to keep themselves. Thirdly, withholding nutrition and hydration will lead us down a slippery slope. Death with dignity will become under pressures of undertreatment the “obligation to die.”

These arguments merit serious consideration, but they are not finally persuasive. Nutrition and hydration procedures themselves sometimes involve discomfort and indignity, such as pain from a central IV and physical restraints which prevent patients from removing lines or tubes. It is also misleading, if one goes by the neurological consensus, to project the common experience of hunger and thirst on patients in PVS. Such patients feel neither hunger, thirst nor pain. This provides no leave to “starve” them. The issue is whether or not it provides sufficient medical justification for keeping them alive.

The fears underlying the third argument are more troubling because of uncertainties regarding whether lines can be drawn and maintained in order to prevent abuses. Vulnerable patients are particularly at risk here, eg those in nursing homes.

In making decisions on their behalf caregivers should remind themselves that the protection of the weakest is an essential component of the social contract. But again, this does not mean that provision of nutrition and hydration should be obligatory in all circumstances.

From a practical point of view, the Schiavo dilemma highlights the importance of having either a living will or a durable healthcare power of attorney. One difficulty here of course is that no 20-year old ever thinks that they need either. But had Schiavo chosen one of these options to give some indication of her wishes under circumstances similar to what befell her, no legal or ethical dispute would have followed.

A second perhaps more important issue raised by the dilemma is that of quality of life. Some forms of life in medical extremity seem worse than death. In those situations what medical technology seems to be able to do is to prolong vitalism, not life in any sense we would recognise as worthy of the name. How can one describe the ethical obligation, if there is one, to prolong vitalism?

The Schiavo situation has generated much talk about the need to promote a “culture of life.” With the general trajectory of this vision, I entirely agree. But general appeals to a culture of life are no substitute for the hard analysis and decision-making often entailed in determining whether this or that is an instance of “life” that should be promoted. There is often a tragic calculus involved in these determinations, and generalities here do not provide much help.