Criteria for Brain Death has Worldwide Medical Consensus

15 Feb 2007, The Straits Times

Question

Name of the Person: Andy Hosenior Writer

Criteria for Brain Death has Worldwide Medical Consensus

LIFE MATTERSTHERE was a three-hour stand-off at the Singapore General Hospital last week when the family of a brain-dead stroke patient tried to stop doctors from harvesting his organs, as permitted under the law. 

Brain death is said to be the complete and irreversible cessation of brain activity, but the man's next-of-kin had noticed tears rolling down his cheeks when they spoke to him, while his elder brother said he even squeezed "my hand when I held his". Doctors say these are just reflexes prompted by the spinal cord, not the dead brain. Families in these situations often ask: Is my loved one really dead?

This tormented ambivalence arises from the conceptual untidiness that "brain death" entails. Up to the 1960s, death was uncontroversially deemed to have occurred when all of a person's major organ systems ceased to function. To this day, no one doubts that a cold, stiff and grey body is dead, but the brain-dead are still pink and warm.Yes, a person hanging from the gallows has lost all brain function and is quite dead. So if the brain is dead, the person must be too. Yet, if ventilated,brain-dead persons can digest food and excrete waste, heal wounds and even carry a pregnancy to full term. Thus while doctors refer to the brain-dead as "cadaveric donors", they do not look or behave like bodies in the morgue. In the brain-dead, the crucial part that is gone is the brain stem, or the lower part of the brain that is continuous with the spinal cord. The brain stem is responsible for human alertness, arousal from sleep, breathing, blood pressure and heart rate control, and it relays information between the spinal cord and the upper parts of the brain. When the brain stem stops working, the brain cannot transmit data to the body to control the heart and lungs, say. Also, it cannot receive data from the body. The patient thus shows no reaction to stimuli, no evidence of thought or consciousness and no ability to breathe on his own. Such a patient can be kept going with life-support for up to three months,before the heart also stops, as the brain turns into mush and the heart rate centre dies. But while on a ventilator, the person still looks alive, or justasleep, so how can he be (brain) dead, family members would ask. 

Brain death differs, however, from the persistent vegetative state - like a Terri Schiavo - where the patient is permanently unconscious but has sleep/wake cycles: The eyes may open during the waking phase but the person remains unaware of the surroundings. In such cases, clinical testing shows that the brain stem is intact - so no ventilator is required, say - but the upper parts of the brain are totally non-functioning. In the brain-dead, by contrast, we do not know if the upper brain is completely dead. For even if we concede that the patient's consciousness is irreversibly and irretrievably lost, there is no proof that the content of his consciousness that was present (in his upper brain) is also permanently gone.That content includes a person's private thoughts, memories, plans, attitudes, etc. Since they are subjectively experienced, there is (still) no way to provethat they are now absent. If so, the whole idea of brain death may have been built upon an unproven hypothesis. It does not help matters when brain-dead persons can also make complex movements, such as placing their hands in a praying position. Then there is the Lazarus sign, which "starts with stretching of the arms, followed by crossing or touching of the arms on the chest, and finally falling of the arms alongside the torso", according to a report in the Journal of the American Academy of Neurology in 2000. It noted that "these movements are more common than has been reported or believed". In the study, 40 per cent of cases had such movements, all within the first 24 hours after diagnosis, but none after 72 hours. Sometimes, drugs to paralyse the patient are used to prevent these movements from occurring during surgery to remove the organs. 

There is also evidence that the upper brain continues to regulate some bodily functions, including electrolyte and hormone metabolism, which are controlled by the hypothalamus, a part within the upper brain. In some countries, where high-tech tests are used to confirm the diagnosis of brain death, significant brain function may be detected in about 20 per cent of cases. These tests include those in which brain cells actively take up radioactive drugs or produce "evoked potentials", which are electrical potentials recorded following a stimulus, such as a sound presented through earphones. (Evoked potentials are distinct from spontaneous electrical potentials that can be recorded from the surface of the head as normal brain waves.) In some cases, even normal brain waves can be detected for up to seven days. Yes, people correctly diagnosed with brain stem failure never ever recover consciousness, but what these tests show is that some brain cells are still functional. Thus not all the brain is dead in the brain-dead - at least some of the time. If so, the very concept of brain death is not internally consistent. 

Moreover, equating brain death with death takes for granted that the brain is the supreme regulator or fundamental orchestrator of all body functions. It assumes that it is the brain that keeps a person's total physiology integrated. However, many experts today argue that it is unclear if there is a supreme regulator at all. The evidence is, rather, that all bodily systems need to co-equally function for life to be sustained. Since the very notion of brain death is problematic, the next-of-kin should not be told that the patient is brain dead, and thus legally dead for the purposes of organ harvesting. What should be explained instead is that his brain stem has suffered irreversible damage and that total cessation of brain function is just a matter of hours or days away and that the patient cannot be kept alive with heroic measures indefinitely. In such futile cases, consent to have life support withdrawn is sought from the next-of-kin. This is not euthanasia: It is perfectly acceptable for a person to have a doctor turn off his ventilator, which would result in his death. 

This is because we have the right not to have things done to our bodies against our will - lawyers call it "battery" - even things that could keep us alive. The family is advised that life support will be unplugged in the operating theatre instead of the hospital ward. Family members say their final goodbyes outside, the patient is wheeled in and he is then unplugged. Although the heart could theoretically be resuscitated (as long as the brain has not yet completely liquefied into mush), if pulling the plug is ethically acceptable in futile cases, then not resuscitating the heart would also beacceptable. Within a few minutes, the heart stops. Some 15 seconds later, the brain begins to shut down completely, the signal that stimulates breathing goes, and cells begin to die. 

At this time, the patient is pronounced dead and surgeons begin immediately to remove his organs. With the family's pre-obtained consent, however, doctors would have already been running cool preservatives through the organs to reduce damage from the lack of oxygen once the plug is pulled. Without ever employing the notion of brain death, this arrangement - which uses the traditional heart-and-lung criterion to define death - would satisfy the unwritten rule that a donor be dead before his organs are harvested, where harvesting must not itself cause his death. It was, in fact, in this way that the world's first successful liver and heart transplants were carried out in the United States (1966) and South Africa (1967), respectively. The notion of brain death would only be introduced the following year by an ad hoc committee of the Harvard Medical School, explicitly to free up beds in their intensive care units and expedite organ procurement for transplantation. Their report, however, presented the already contested connection between the loss of brain function and death as if it were fact. Though there was already a large body of work on the issue, the paper made scant reference to that scientific literature. 

But the glow of the Harvard name - and its publication in a well-regarded journal - quickly turned hotly disputed ideas into indisputable fact. (Yes, scientific "truth" can be socially constructed.) To this day, though most protocols that doctors use to declare someone brain dead are still based on the Harvard recommendations, the veracity of this notion of brain death is hotly contested. If nothing else, given its ethically questionable provenance, it may be high time to let brain death die. 

Reply

Name of the Person: Dr Arthur Chern

Director Integrated Health Services Division

Ministry of Health

Name of the Person: Assoc Prof Thomas WK

LewHead, Department of Anaesthesiolog

Tan Tock Seng Hospital

I refer to the commentary by Mr Andy Ho - "It's time to lay to rest brain death" (Straits Times, 15 Feb 07). 

We do not agree with Mr Ho's assertion that the scientific truth behind brain death was "socially constructed" or with his claims that the medical definition of brain death is internally inconsistent with the scientific evidence and observations. While Mr Ho accepts the irreversibility of brain death, he recommends its abandonment and reversion to the sole cardiac-respiratory definition as death. This view, while held by a minority, is not supported by worldwide medical and societal consensus. 

The notion of brain death was first described and published by two French neurologists in 1959 and was further examined by various scientific expert bodies. The Ad Hoc Committee of the Harvard Medical School published its report in 1968 and the University of Pittsburgh published its brain death criteria in 1969. In 1971, the Minnesota criteria was published. The first nation in the world to adopt brain death as the definition for legal death was Finland in 1971. In 1979, the Conference of the Medical Royal Colleges and their Faculties in the United Kingdom indicated that "brain death represents the stage at which a patient becomes truly dead". In 1981, the medical consultants to the US President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioural Research published guidelines on the determination of death based on neurologic criteria. Other national medical entities have independently and separately arrived at similar criteria and definition. 

Published evidence accumulated over the years has shown that the stoppage of the heart was the invariable outcome for persons diagnosed with brain death but maintained on a ventilator. Over a thousand of such cases have been observed: they were non-drugged patients who had brain stem death and were maintained on ventilators. There was a nil survival rate and in most cases stoppage of the heart developed within days Christopher Pallis. ABC of Brain Stem Death: Prognostic Significance of A Dead Brain Stem. BMJ 286; 1983. 

When a person is declared brain dead, it does not necessarily imply death of every cell in the body, and some movements are sometimes observed. After brain death, if the heart continues to beat long enough, the dead patient may still have some functioning nerve cells allowing for pathological limb reflexes "Lazarus reflexes"). The presence or absence of these reflexes may tell us that the spinal cord is alive or dead but does not indicate that the person is alive. Similarly, even after an irreversible cessation of heart beat and respiration, not every cell in the body dies immediately. 

Brain death is a widely accepted condition by international medical communities. The clinical criteria prescribed by law in Singapore were based on international standards on diagnosing brain stem death and were drawn up with the help of our local experts. Worldwide, there has been no reported case of any properly diagnosed brain dead person coming back to life. 

The medical diagnosis and establishment of brain death is not a means to organ donation for transplantation. The medical diagnosis of brain death as a legal definition of death and its consequence of leading to discontinuation of futile support of some of the body functions, offers a dignified and definitive closure to the family of patients who have passed away. A call for its abandonment is not to be taken lightly.