Ruminations on Death

The World Congress of Bioethics is being held in Bangalore next month. There is a pre-congress workshop for transplant coordinators where ethical issues related to brain death and organ donation are going to be discussed. One of the issues being discussed is how we define death.

Before organ donation became an integral part of modern medicine, there was little discordance between the medical definition of death and the religious ones. If the heart stopped beating and the breathing stopped (usually in rapid succession), and if efforts to restart them failed then the person was declared dead. Religious leaders who defined death as the soul leaving the body were happy to confirm that the moment of the departure of the soul was when the heart stopped beating. It is still common for people who have recovered after a cardiac arrest to claim that they died and came back. Images created by disordered firing of neurons short of oxygen were interpreted according to the cultural norms of the society. In Western Christian societies patients report traveling through a tunnel towards a light. They report being outside the body and seeing it from above. Curiously enough, Indians and other Eastern societies do not report such images.

The heart had long been considered the most important organ in the body. It was central, excitingly dynamic, and obviously vital to life. Emotions were thought to be controlled by the heart and most languages still have a vocabulary that assumes the heart to be the center of emotion.

In the early 1600s, William Harvey struck what should have been a fatal blow to this doctrine. He described the circulation of blood through the body and established that the heart is merely a mechanical pump.

All the mystical qualities associated with the heart have long been known to reside in the brain. Emotions are felt in the brain. Memories are stored in the brain. Our intelligence comprises of our ability to use our brains to reason. Consciousness resides in the brain. We can switch it off with drugs. This is called anesthesia. Or sedation.


It has become increasingly clear that the definition of death using the cessation of heartbeat is not adequate. It is true that until recently in human history, a person whose heart stopped beating, soon lost consciousness because the brain stopped getting oxygen and the electrical activity in the brain stopped, leading to loss of consciousness. However, sometimes the sequence is reversed. The brain is injured. Breathing stops without the brain running the respiratory center but if the patient is put on a ventilator which takes over the function of breathing, the other organs can be sustained for quite some time.

We can replace the functions of the heart and lungs with a machine during surgery on the heart. We can replace the heart with a pump. Obviously a person with an artificial heart is still alive. We cannot replace the functions of the brain. We are a long way from mapping the pathways of the brain, recording memories from the brain and transferring them to a computer. Perhaps when we are able to do that we will have to change the definition of death again.

If a brain injury is such that all blood flow to the brain had stopped, the cells in the brain die. The electrical potential difference across the cell membrane of the cells is lost as they run out of energy to run the pumps which maintain the difference in electrical potential and chemical composition across the cell membranes. The enzymes which run the internal processes of the cells stop working (most of them require energy to work). The cell membranes break down. The brain turns into a blob of jelly. There is a drop in blood pressure when the brain cells die and release a flood of toxic products into the blood. This is called the cytokine storm.

Obviously, the death of the brain means the permanent end of consciousness. It is this permanent end of consciousness which is now defined as death. There are simple clinical tests which can be performed on the body to confirm death.

Tests of Brain Death
There are simple tests which can confirm that the brain is dead. These can be done by the bedside. In case of doubt, there are other tests which can be done for confirmation. There have been no instances of a person declared brain dead regaining consciousness. Such cadavers have been kept 'maintained' on ventilators for long periods of time by families who refused to accept that the person is dead, often for religious reasons, but there has not been a single instance of the cadaver regaining consciousness. On the other hand there have been occasions when cardiac death has been misdiagnosed and the supposed deceased has woken up during the funeral proceedings.

The tests for brain death are simple:

• The apnoea test. Without going into details of how this test is conducted, this confirms that when disconnected from the ventilator, no breathing takes place.
• The cold caloric test. When the brain is intact, pouring cold water into the ear stimulates the inner ear (which is responsible for balance) and the eyes move in response to the stimulus.

Although these tests are sufficient, in case of doubt, other tests can be done.

• The electroencephalogram. Measurement of the electrical activity in the brain using electrodes placed on the head is normally used to look for abnormal activity in patients with epilepsy but can be used to confirm brain death as well. It's not a very good test because some electrical activity can come from muscles and nerves under the scalp even in brain dead cadavers.
• Blood flow into the brain. In brain death, there is no blood flow into the brain. This can be confirmed by doing a trans-cranial Doppler study, a carotid angiography or a radioisotope scan in which a radioactive tracer is injected into the blood and a scan is done to confirm that none of it reaches the brain.

Most religions now accept that brain death is a viable form of death. After all, transplantation of the heart has demonstrated that the body could be dead and buried while the heart could be beating in someone else's body.

This also brings us to the often misunderstood concept of a brain or head transplant. Consider someone like Stephen Hawking, trapped in a body progressively debilitated by a muscle wasting condition. Could we take his brain (or much more practically, his head) and attach it to the body of a brain dead person whose other organs are functioning well? Although in a physical sense, his head would be removed and attached to the other body, in a practical sense, everything that makes him Stephen Hawking, is in his brain. His memories, intelligence, personality and consciousness reside in his brain. It would be Stephen Hawking who would wake up after the operation, not the person who became brain dead. There are practical problems with doing a head transplant which have not yet been solved (apart from waking up with somebody else's fingerprints), mainly how to connect the spinal cord and other nerves. However, if it were possible, the head would be the recipient and it would more correctly be referred to as a 'whole body transplant'.

Which brings us to the Ganesha myth. The story goes that Shiva returned home and found Ganesha guarding the house. Not knowing that Ganesha was his own (or at least his wife Parvati's given that some versions say she made him out of earth and some say she used turmeric paste from her body to make him) son, Shiva gets irritated with him when he refuses to let him in and beheads him. Parvati emerges and is justifiably annoyed with her intransigent husband and tells him to fix the mess he has made. Ganesha's head, apparently, is not locateable and Shiva decides to replace it with a spare and sends his cohorts to find him another head. They return with the head of an unfortunate and blameless elephant. He attaches this head to Ganesha's body, having sorted out the issues with xeno-histocompatibility and the nerve and spinal cord reattachment issues. This supposed feat of surgery would later lead Mr Modi to wax lyrical about how developed surgery was in ancient India1. However, the point often missed is that such an undeniable feat of surgery would result in the elephant waking up with a human body, not Ganesha waking up with an elephant head.