I have already Commented on the question, Are those who fail to pass brain stem function tests really dead? (read blog entry Organ-donation – Are Brain Dead Really Dead?) In this entry I would like to consider another approach to the claim that those who are brain dead are really dead.
The argument accepts the biblical view that when a person is dead then the neurologic (brain), circulatory (heart), and respiratory (Lungs) systems are each dead.
In order to maintain the biblical requirement for death, the argument goes something like this. The brain stem is responsible for maintaining life, such that without brain stem function, the body will die. Since brain stem function is necessary for other organ systems to continue to function, the reason why other organ systems may continue to function is because they are being artificially supported. If the artificial support is discontinued, then these organ systems would cease to function as well. The implication is that, since these organ systems are being supported artificially, their life is really artificial, that is that they are not really living and the person is dead.
This argument supports the idea that death includes death of each of the neurological system, the circulatory system and the respiratory system, that is, that the diagnosis of death requires loss of brain, lung and heart function inclusively. The arguments says that the brain stem is not functioning and therefore must be dead. The circulatory system without artificial support will cease to function and therefore is artificially functioning and must be dead. The respiratory system without artificial support will cease to function and therefore is artificially functioning and must be dead. Since each of the neurological (N) system, the circulatory (C) system and the respiratory (R) system are not functioning the person (P) is dead. A short form of this argument is that N and C and R all need to be dead for P to be dead. Since N and C and R are dead, P is dead. Shorten this again to, since N and C and R are all true then P is true.
It follows that if N, C or R is not true then P is not true. It follows that if one of the systems continues to function without artificial support that the person is not yet dead.
Now, consider the case where a person’s brain is functioning but the part of the brain stem that drives respiration is destroyed such that the respiratory system will irreversibly not function without artificial support. The person is conscious, but totally dependent on artificial respiration. Using the same definitions as above, the respiratory system without artificial support will cease to function and therefore is artificially functioning and must be dead. Is it right to think of part of a person being dead and part of them alive, at the same time? A person who is alive with a gangrenous foot (a dead foot) remains a living person. We do not say the person is part living and part dead. It is ridiculous in the case described to say that the respiratory system that is totally dependent on artificial support is dead. It is simply malfunctioning. Therefore, in the argument presented above, the most we can say about one of the major systems (neurological, circulatory, respirator) when it is totally dependent on artificial support is that it is malfunctioning. We can not, with certainty, conclude that it is dead.
Also, consider what happens in many cases. The person’s brain stem is found to not be functioning and is said to be dead. A variety of brain stem reflexes are used to support this assessment. The person is not breathing spontaneously and the “none functioning” respiratory system is supported by a mechanical ventilator. The respiratory system is proven to not be functioning by performing an apnea test, when the ventilator is turned off and and the persons lungs fail to inflate.1 But the heart continues to beat on its own. Proponents of the argument say that the circulatory system is being artificially supported by drugs that cause arterial vessels to constrict. These drugs are necessary to keep the blood pressure up. These drugs are considered to be the artificial support that without the circulatory system would fail. The dependency of the circulatory system on this artificial support is not as clear as it is for the respiratory system’s dependency on the mechanical ventilator. When a mechanical ventilator is stopped the lungs stop moving immediately. When the drugs to help maintain blood pressure are stopped, the heart does not immediately stop pumping blood. Unlike the respiratory system that can be tested with the apnea test, there is no test to prove that the circulator system in a particular patient will cease to function without the artificial support of drugs. A similar test would be to stop the drugs until the heart stops. This is not done, for it would then compromise the viability of the wanted organs. This means that the assertion, that because the circulatory system is artificially supported and that if the artificial support is withdrawn it will cease to function, is only assumed. There is no way to test if the assumption is really true.
1. It is also important to note that the apnea test does not really prove that the respiratory system is dead. All it proves is that there is not muscular movement of the chest wall in response to the absence of ventilation along with a significant increase in CO2 (carbon dioxide) in the blood. Normally, increases in carbon dioxide in the blood are associated with and increase in the depth and speed of lung movement. This is more a test of the function of the brain stem drive of the muscles that move the lungs, then it is a test of the respiratory system as a whole. The respiratory system is much more than the movement of the chest wall that moves air in and out of the lungs. It is a living system that includes a special mucosal lining and blood vessels in the lungs to move gases between the air and the blood. This part of the respiratory system is not artificially supported. In a sense, it is only part of respiratory system that is artificially supported.
Considering all of these things, the most that one can accurately conclude when brain stem functions tests do not demonstrate that the brain stem is functioning is that the brain stem is not functioning. More information is required to know for sure that the brain stem is dead. And even if we are certain that the brain stem is dead, we can not know for certain that the person is dead until the circulatory and the respiratory systems have been allowed to cease to function in the absence of artificial support. This is based on the the requirement that the each of the neurological, circulatory and respiratory systems all be dead for the person to be dead.
Intuitively, if any one of the neurological, respiratory, or circulatory system ceases to function and is not supported artificially then death of the other two systems will follow. In other words, if one system ceases to function, irreversibly the person is dying. It is when all three systems cease to function that we can know that the person is really dead..