Brain stem death

Brain stem death - Illnesses & conditions | NHS inform Home Illnesses and conditions Symptoms and self-help Tests and treatments Healthy living Care, support and rights Scotlands Service Directory 0 Home Illnesses and conditions Brain, nerves and spinal cord Brain stem death Brain stem death Brain stem death is when a person no longer has any brain stem functions, and has permanently lost the potential for consciousness and the capacity to breathe. When this happens, a ventilator keeps the persons heart beating and oxygen circulating through their bloodstream. A person is confirmed as being dead when their brain stem function is permanently lost. Confirming death Confirming death used to be straightforward. Death was said to occur when the heart stopped beating and a person was unresponsive and no longer breathing. The lack of oxygen as a result of no blood flow, quickly led to the permanent loss of brain stem function. Confirming death is now more complex, because its possible to keep the heart beating after the brain stem has permanently stopped functioning. This can be done by keeping a person on a ventilator, which allows the body and heart to be artificially oxygenated. However, that person wont ever regain consciousness or start breathing again. Once the brain stem has permanently stopped functioning, theres no way of reversing it and the heart will eventually stop beating, even if a ventilator continues to be used. To save a persons family and friends from unnecessary suffering, once theres clear evidence that brain death has occurred, the person will be disconnected from the ventilator. The brain stem The brain stem is the lower part of the brain thats connected to the spinal cord (part of the central nervous system in the spinal column). The brain stem is responsible for regulating most of the bodys automatic functions that are essential for life. These include: breathing heartbeat blood pressure swallowing The brain stem also relays information to and from the brain to the rest of the body, so it plays an important role in the brains core functions, such as consciousness, awareness and movement. After brain death, its not possible for someone to remain conscious. How brain death occurs Brain death can occur when the blood and/or oxygen supply to the brain is stopped. This can be caused by: cardiac arrest  when the heart stops beating and the brain is starved of oxygen heart attack  a serious medical emergency that occurs when the blood supply to the heart is suddenly blocked stroke  a serious medical emergency thathappenswhen the blood supply to the brain is blocked or interrupted blood clot  a blockage in a blood vessel that disturbs or blocks the flow of blood around your body Brain death can also occur as a result of: a severe head injury a brain haemorrhage infections, such as encephalitis a brain tumour Vegetative state Theres a difference between brain death and avegetative state, which can occur after extensive brain damage. Someone in a vegetative state can show signs of wakefulness  for example, they may open their eyes, but not respond to their surroundings. In rare cases, a person may demonstrate some sense of response that can be detected using a brain scan, but not be able to interact with their surroundings. However, the important difference between brain death and a vegetative state is that someone in a vegetative state still has a functioning brain stem, which means that: some form of consciousness may exist breathing unaided is usually possible theres a slim chance of recovery, because the brain stems core functions may be unaffected Aperson who is brain dead has no chance of recovery, because their body is unable to survive without artificial support. Confirming brain death Although rare, a few things can make it appear as though someone is brain dead. These include drug overdoses (particularly from barbiturates) and severehypothermia (where body temperature drops below 28C). Therefore, a number of tests are carried out to check that brain death has actually occurred, like shining a torch into both eyes to see if they react to the light. Organ and tissue donation After brain death has occurred, it may be possible for the persons organs and tissue to be used in transplantations. This can often save or improve the lives of others. Only 1% of people die in a way that makes organ donation possible. This means every opportunity for donation is very precious. Specialist nurses will discuss the possibility of donation with families. Thisll be done in a sensitive way. Theyll also check the NHS Organ Donor Register to see if the person had recorded a donation decision and share this information with the family. This lets the family know what their loved one wanted. It also means that nurses can check if this was their latest view. Further information about organ and tissue donation Diagnosing brain stem death There are a number of criteria for diagnosing brain stem death. For a diagnosis of brain stem death to be made: aperson must be unconscious and fail to respond to outside stimulation apersons heartbeat and breathing can only be maintained using a ventilator there must be clear evidence that serious brain damage has occurred and it cant be cured Ruling out other conditions Before testing for brain stem death, doctors must carry out a series of checks to ensure that the symptoms arent being caused by other factors, like: an overdose of illegal drugs, tranquillisers, poisons or other chemical agents an abnormally low body temperature (hypothermia) severe under-activity of the thyroid gland Once these factors have been ruled out, tests are carried out to confirm brain death. The diagnosis of brain death has to be made by two senior doctors. Neither of them can be involved with the hospitals transplant team. The doctors will explain the tests to you and theyll keep you informed about your loved ones condition at all times. Tests The doctors will run a series of tests. Both doctors have to agree on the results for a diagnosis of brain death to be confirmed. The tests are carried out twice to minimise any chance of error. The tests used to determine whether brain stem death has occurred are outlined below: A torch is shone into both eyes to see if they react to the light. The cornea (transparent outer layer of the eye), which is usually very sensitive, is stroked with a tissue or piece of cotton wool to see if the eyereacts. Pressure is applied to the forehead and the nose is pinched to see if theres any movement in response. Ice-cold water is inserted into each ear, which would usually cause the eyes to move. A thin, plastic tube is placed down the trachea (windpipe) to see if itprovokes gagging or coughing. The person is disconnected from the ventilator for a short period of time to see if they make any attempt to breathe on their own. Brain death will bediagnosedif a person fails to respond to all of these tests. Occasionally, a persons limbs or torso (the upper part of the body) may move, even after brain stem death has been diagnosed. These spinal reflex movements are generated by the spinal cord and dont involve the brain at all. Therefore, they wont affect the diagnosis of brain death.