The science of determining when life is over
by Cushla McKinney
With the advent of technologies such as life-support systems, we can now save the lives of people who would once have died. For example, we can now maintain the basic physical functions in patients with profound damage to the brain-stem (the region that controls basic functions such as heartbeat and breathing rate). This has led to a broadening of the definition of death to include both the ‘irreversible cessation of circulation and respiration’ (heart death) and the ‘irreversible ‘cessation of all functions of the entire brain’ (brain death).
It has also led to situations where we have to ask not whether we can keep a patient alive, but if we ought to do so. When and how do we decide to stop treatment and let the patient die? Some of the most difficult of these decisions take place when a person’s body remains healthy but their brain is profoundly, possibly irrevocably damaged. Not all severe brain injuries result in permanent loss of lower-brain function and brain death. Some coma patients recover to the point where they are able to breathe unaided, and exhibit some signs of life.
The critical questions then becomes whether the person is aware of his or her surroundings, and whether consciousness is likely to return. Because we can only infer consciousness by examining another person’s behaviour, profoundly brain damaged patients are divided into categories based on observable criteria and the extent and location of injury. Of particular relevance to this discussion are persistent vegetative state (PVS), minimally conscious state (MCS), and locked-in syndrome.
These classifications have important implications with respect to prognosis, therapy, the ability to consent to or refuse treatment, and the legality of withdrawing treatment. Given the profound implications of such decisions, the need to accurately diagnose when a person with brain damage can no longer benefit from treatment is a critical one. In February, a paper published in the New England Journal of Medicine suggests that just as technology has created the problem, it may also provide the solution.
In order to explain the nature of this dilemma, let me take you back 17 years to a precedent-setting case heard by the British House of Lords:
On the 15th of April 1989, a UK teenager named Anthony Bland was watching a football match at the Hillsborough Football Stadium. More and more spectators pressed into the spectator pen in which Anthony was standing, and in the resulting crush he was unable to breathe. Although eventually resuscitated, his cerebral cortex (the area of the brain that controls awareness) was irreparably damaged. His body continued to breathe, his heart to beat, and his digestive system to function, but the thinking, feeling consciousness that was Anthony Bland no longer existed. Four years later, the British House of Lords authorised the removal of his feeding tube. because it served no humane purpose. Whilst it could have kept him alive for many years, it could not restore him to having life in any sense at all, and the Court felt it likely that were Anthony were in a position to make the choice himself, he would prefer to die rather than live as he was.
In reaching this decision, the Law Lords made two important and apparently quite reasonable assumptions. Firstly, they decided that ‘Anthony Bland’ no longer existed, and because there was no way to reverse his catastrophic injury, any further treatment was futile. If a medical procedure is likely to be of little or no benefit to a patient, a physician is under no duty to provide it, and if the treatment is not in the patient’s best interests, they are obliged not to do so.
Secondly, they considered that Anthony himself would, if he were able, ask for the feeding tube to be removed. Every competent person has the right to refuse medical treatment, even if it this will result in their death. This right does not disappear simply because somebody is unable to make or communicate treatment decisions. In these situations, a substantiated judgement is made; what, based on knowledge of the patient’s beliefs, values and hopes and desires, would he have wished to be done in this situation. In some cases there may be clear indications of what person is likely to have chosen. A Jehovah’s Witness would probably refuse to accept a blood transfusion for example, while a devout Catholic who believes in the sanctity of life would want life-sustaining intervention. In other cases, a determination is made based on the way a person has lived and whether continued intervention is in keeping with who they are.
Keeping Anthony’s body under such circumstances (which he himself would most likely not have wanted) was wrong. It not only demeaned his dignity and the memory of the person he was, it failed to respect his right to live and die in the manner he would have wished. Regardless of whether the decision rests on whether ongoing treatment was of any benefit, or whether it was in keeping with Anthony’s life story, the conclusion would be the same. Allowing him to die was not only lawful, but morally right. The Bland case also set the legal precedent that, under certain circumstances, the withdrawal of artificial nutrition and hydration is not necessarily euthanasia. Like any other medical treatment, it may legally be withheld.
Similar decisions have been made in New Zealand courts. One such case involved case of a patient completely paralysed by with Guillian-Barr Syndrome and unable to communicate although conscious (a type of locked-in syndrome). The removal of his ventilation tube was declared lawful because specialists agreed there was no hope of recovery, and there was general agreement that he would not want to be left in such a state. In another, the removal of nasogastric food and fluid from a man who suffered severe and irreparable brain damage in a road accident was authorised by the courts on similar grounds. Both these decisions rest on the determination that neither patient would have wished treatment to continue, and that removing life-support allowed the patients to die peacefully, with the greatest dignity and least distress (the alternative being to wait until they developed pneumonia or some other illness, then withhold antibiotics).
One concern that many people will have about cases such as those described above is that decisions to withdraw treatment are motivated, at least in part, by financial considerations. After all, if there were a duty placed on those caring for such patients to keep them alive as long as medically possible, this would be at the cost of other patients also needing limited health resources. Both the High Court and the old Court of Appeal have accepted that resource constraints as well what is in the patient’s clinical best interests may be a relevant in determining whether it is lawful to withdraw treatment. Although medical care in New Zealand is provided on the basis of need, and we don’t place a monetary value on life, there has been an attempt to develop a formula to arbitrate between needs on the basis of QALYs (Quality of Adjusted Life Years). These measure both the number of years a person would gain from treatment, and the quality of those years. Because a coma or PVS patient might be kept alive for a considerable time by life support, these would be regarded as of little or no quality of life and he or she thus less needy than a patient more likely to benefit from treatment.
Although such fears are reasonable, any decision to cease treatment must be firmly grounded on the presumption that the patient would not wish to continue receiving it. The critical factor is that ongoing intervention provides no substantial benefit to them (and that their consent to treatment would have lapsed), not that their ongoing treatment is prevented another person from receiving care. Court decisions here and internationally have stressed that the interests of the patient are the primary concern – and this is consistent with the duty of care doctors owe to their patients. This same duty, however, also means that a doctor ought not keep a patient alive in what would, to them, be an unacceptable state. Respect for the person’s dignity and integrity, not financial considerations, that guides these painful and difficult decisions.
The damage that leads to a vegetative or minimally conscious state occurs in the cortical regions that interpret sensory inputs and control those phenomena that we generally think of as evidence of consciousness; language, mathematical and artistic ability, logic, and imagination. Because the areas of the brain that control, among other things, visual and auditory reflexes and sleep, patients in a vegetative or minimally conscious state will open their eyes, and develop a ‘normal’ sleep/wake cycle with periods of apparent arousal.
A patient in a vegetative state will give no sign of awareness or meaningful response to commands or questions and their movements or behaviours are reflexive rather than contingent on environmental stimuli. In some cases signs of awareness may return, but if the patient remains non-responsive for 6-12 months, their condition considered likely to be in an a permanent and a diagnosis of PVS is made.
As ethicist and neurosurgeon Grant Gillett points out, the fact that we recognise and respect a person’s right to a dignified death implies that ‘life’ (and sanctity of life) refers to more than biological functioning. He describes life as a ‘lived narrative’, requiring personal identity (the sense of oneself living this life, with these people), conscious awareness, and intentional action and interaction. In the case of Anthony Bland and other PVS patients, the awareness of and interaction with the world, and thus their ability to experience a ‘lived’ life are irrevocably lost, and thus prolonging the life of their body was futile.
How certain can we be in making such judgements, however? What if the person is still aware but trapped inside a non-responsive body? Although it sounds the stuff of nightmares, locked in syndrome (LIS) is a very real phenomenon that occurs when the motor cortex is damaged, leaving a person fully conscious but unable to communicate except (sometimes) by moving their eyes. The most famous LIS patient is Jean-Dominique Bauby, journalist and former editor of Elle, who suffered a massive stroke at the age of 42. Despite almost total paralysis (he communicated by blinking his left eye once for ‘yes’, twice for ‘no’) he narrated a memoir of his life and experience with LIS called the ‘Diving Bell and the Butterfly”, later adapted into an award winning film. In it, he describes the wonderful life of the mind that survived the loss of his body, and similar narratives have come from other LIS patients. Once they are able to establish a means of communication and interaction, they rate their quality of life remarkably highly, and wish to continue to live, despite their limitations.
Patients in a minimally conscious state occupy a halfway house between PVS and LIS. They will show signs of definite evidence of some degree of awareness of themselves or their surroundings (for example focussing on or following movement), although their ability to respond to commands or indicate answers to yes/no questions may be variable, or absent. As with coma and PVS patients, decisions are sometimes made to discontinue treatment, usually when patients or relatives initiate a review of the situation. In some cases the patient may be able to give some indication of their wishes, in others the decision will rest on whether
In some cases this awareness may be minimal, and treatment may be judged futile, but it is estimated that up to 40% of those diagnosed as being in PVS actually possessed the ability to spell messages, make choices, or were orientated to time and place. They retain the ability (albeit diminished) to experience and interact with the world, and thus maintain a hold onto their ‘lived’ life. Not only may they may have the ability to make decisions on their own behalf, we cannot automatically assume that they would not choose to live this way if they are able to do so, as the accounts of people with locked-in syndrome clearly demonstrate.
With time and intensive therapy, they may be able to recover some ability to communicate and control their bodies, but if such therapy is not initiated soon after awareness returns, they may be unable to attain any reasonable quality of life. Because legal competence requires people to have both the ability to make reasoned decisions and to convey their decision to others, it is clinically, ethically and legally important to find ways to establish communication.
Under New Zealand law, the decision to withhold or cease treatment are clinical decisions made by the physicians in charge of the case – and not, as many people believe, by the family, unless somebody has been granted guardianship or power of attorney over the patient. Although this may not be widely known, Right 7 of the Patient’s Code of Rights states that: “Where a [patient] is not competent to make an informed choice and give informed consent…the [doctor] may provide services where it is in the best interests of the [patient]; and…that [this] is consistent with the informed choice the [patient] would have made.”
In fact, even if a legal guardian requests treatment, it may still be withheld or withdrawn because is unlikely to benefit the patient ¬– either because there is little or no prospect of therapeutic success, or because the result of intervening will leave the patient in an unacceptably bad state.
Not only are doctors under no legal (or ethical) obligation to provide futile treatment, they have a duty not to intervene in ways that are not in the patient’s best interests. Providing that the decision is in keeping with acceptable medical practice, discontinuing life-sustaining measures is lawful, even though will result in the patient’s death.
This is not to say that family members do not play an important role in the process – they are an important source of information about what the patient would have wanted. In addition, the decision to discontinue (or withhold) treatment will have profound consequences for those who love and care for the patient, doctors are reluctant to act against a family’s wishes.
Dr Mike Hunter, the director of Dunedin Hospital’s ICU, says that he waits until the family has come to accept the decision before acting, but adds that removing the responsibility from the family also relieves them of the pain, guilt and potential conflict of having to make that choice themselves. Similarly, one of the charge nurses describes her job and duty of care as extending to the family, especially if this is somebody’s first experience of death, because this experience will stay for them for the rest of their lives.
Given the diagnostic uncertainty in cases of brain injury and the fear of condemning a fully conscious person to death many people are likely to be uncomfortable with the idea of withholding life-sustaining treatment of patients in PVS or MCS. In addition, there are rare but regular news stories about patients who have been declared dead only to spontaneously show signs of recovery (one man most dramatically last year just as the family were preparing to say farewell prior to donating his organs). This is enough for many families to think twice when faced with the prospect of a loved one’s life support being turned off.
It is even harder in cases such as Anthony Bland – or more recently, in the controversial case in Florida of Terry Schiavo – where a person has no conscious awareness but whose body continues to function without artificial support. How can we be sure that they are, to all intents and purposes, dead?
This is where the research reported in the New England Journal of Medicine is significant. Functional magnetic resonance imaging (fMRI) has been used for a number of years to supplement behavioural observation as a diagnostic tool. fMRI detects changes in blood flow in the brain that indicate neuronal activity, and has been used to assess the extent of brain damage in comatose or non-responsive patients (this was not possible with Terry Schiavo because she had metal implants in her head).
Until now, however, there has been no way to determine whether responses to external stimuli (names, touch etc) reflected conscious thought or are merely reflexive responses. In the February study, researchers attempted to establish virtual communication with 54 patients diagnosed with MCS or PVS. They were asked to imagine playing tennis or visualise walking around a familiar space, and five of them showed increased blood flow to the motor cortex when asked to think of tennis, and to the visual cortex when asked to mentally navigate a room, indicating they heard and understood at least some of what was being said.
One of these patients was also able to accurately answer questions about his family by thinking ‘tennis’ for yes and ‘walking’ for no, the mental equivalent of Bauby’s eye-blinking. Although only preliminary, these results show not only the utility of fMRI for detecting awareness and cognitive function in severely brain-injured patients (critical for distinguishing between PVS and MCS), but also mean that in future some MCS patient previously unable to communicate may be able to make their own treatment decisions. Similarly, it may provide some certainty to grieving friends and family of PVS patients for whom food and fluids have been withdrawn that the person they loved is truly gone.