Should PVS patients be medical research subjects?

Defining what death means

Discussion about the merits and drawbacks of using patients in a persistent vegetative state (PVS) as subjects for experiments in xenotransplantation gathered some notice in ethics circles when the commentaries appeared in October, but according to one ethicist, that aspect of PVS research is unlikely to see serious debate until more is known about the neurologic state.

A discussion in a recent ethics journal centers on whether PVS patients should, with prior consent, be enlisted as research subjects for animal-to-human solid organ transplants and other studies, as well as whether there should be provisions for people to declare when they want to be considered "dead" — suggesting that some might choose that their bodies be declared legally dead if they are diagnosed permanently vegetative, and for their "breathing cadavers" to be used for medical research.

Such suggestions are deemed unpalatable by most in medicine and society, as even one strong proponent states.

"Firstly, it may be put forward that the general public will not welcome such a shift in policy," wrote Belgian researcher An Ravelingien, in a 2004 article.1 Among Ravelingien's more controversial arguments is that PVS patients could be considered already dead, and if so, should not be referred to as "patients" so as not to overly humanize them.

"If permitting willed body donation in case of PVS implies that we go against some of the most fundamental convictions on life and death matters held by relatives, physicians, and the general public, our suggestion could cause public distrust and outrage," writes Ravelingien.

Consent to the unforeseeable?

But Steven Curry, PhD, a University of Melbourne (Australia) philosopher, writes in the October issue of the Journal of Medical Ethics that suggestions such as Ravelingien's — to declare PVS patients as dead — won't work because public opinion would not allow it.2

That is not to say that people who want their bodies to be used for research, if they themselves enter a permanent vegetative state, should not be allowed to, Curry suggests.

"Those who are in a PVS will not ever wake up; they feel no pain or discomfort and have no continuing interest in their own survival... these patients must also have a right to risk that life for the common good," Curry writes.

Among the benefits to using PVS patients for long-term study of transplants is that, unlike so-called "brain dead" patients, who can only survive a finite period on life support, PVS patients often live many years.

"On the one hand, there are powerful ethical and medical reasons for proceeding with research into the transplantation of non-human organs into human patients; whereas on the other, there are equally powerful ethical reasons for blocking whole organ transplant experiments," according to Curry.

But Kathy Kinlaw, MDiv, acting director of the Emory University Center for Ethics in Atlanta, says that such debate is premature, because there is still much that is not known about PVS — including whether it is a permanent vegetative state or a persistent vegetative state. "Persistent," some experts say, suggests that the state is long-lasting, but perhaps not permanent.

"There is good reason to talk about [PVS patients' role in medical research], but I wouldn't want it to move too quickly forward," says Kinlaw. "There is so much discussion on PVS and whether we have an accurate way of diagnosing it, whether there is potential for reversal, and when it truly becomes permanent, then it raises a lot of other questions."

Before debate over introducing PVS patients into research on other diseases, Kinlaw suggests, comes discussion on how PVS patients might teach medicine about PVS.

There are similar discussions in the end-of-life arena, Kinlaw says, regarding patients who are near death, unable to donate their organs and tissues for transplant, but who want to somehow contribute to ongoing medical research.

"In those cases, like with PVS, there has to be much discussion around how we make sure the patients are very carefully protected," she explains. "The ideal would be an adequate method to inform and somehow get consent to the process."

Agreeably, the informed consent aspect is a major obstacle among those who advocate research involving PVS patients, because a healthy adult is unable to know whether he or she would be in that state eventually, and if so, what procedures or studies might be involved.

The consent for research issue is one factor in Ravelingien's advocacy that the process not be for people to consent to being research subjects if they enter a vegetative state, but to determine when they can be declared dead and their bodies donated to research not requiring a living subject's consent.

"The concept of prior consent from a patient in PVS is fairly problematic," says Kinlaw. "So we would be moving toward surrogate consent. There are large concerns about that that I would have, about its appropriateness."

A family member acting as surrogate for a patient in PVS would likely be very troubled by a decision to permit research on a body that is still alive, even if the surrogate knew the patient would be interested in contributing to research in some way, Kinlaw suggests.

"What happens for the relationship between the PVS patient and their family if the nature of the research is somewhat invasive, or it requires that the patient be removed [from where the family can visit or see the patient] for periods of time or permanently?" asks Kinlaw. "That is not dissimilar to when a patient is near death, and the patient were removed physically from the site. There's a real question of how that interrupts the patient-family relationship."


1. Ravelingien A, Morier F, Mortier E, et al. Proceeding with clinical trials of animals to human organ transplantation: A way out of the dilemma. J Med Ethics 2004; 30:92-98.

2. Curry S. Living patients in a permanent vegetative state as legitimate research subjects. J Med Ethics 2006; 32:606-607.


For more information, contact:

  • Kathy Kinlaw, MDiv, acting director, Emory University Center for Ethics, Atlanta, GA. Phone: (404) 727-4954. E-mail: