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When a loved one gets a brain injury, can’t communicate, and is unresponsive, doctors require your input as you agonize over the question whether your loved ones still has a flicker of consciousness.
With the use of functional MRIs, researchers have found that patients with severe brain injuries, can by controlling their thoughts, influence scans of their brain activity and answer simple questions. Though appearing to be in a persistent vegetative stat, they may retain awareness despite showing no evidence of it.
THE STUDY
Using functional magnetic resonance imaging, fMRI, the brain-injured patient is asked to imagine playing tennis or walking through the room of his home. Imagining tennis, activates the motor planning regions in the brain; picturing activity in his house, activates a brain region involved in recognizing familiar scenes.
The patients were asked six questions: imagining playing tennis, would indicate YES to the question asked, and by picturing his home would indicate NO to the question. All the questions involve basic autobiographical details: the name of his father, or whether he had brothers or sisters.
Even though the brain injured patients could never do anything to indicate consciousness in tests at the bedside, they could unambiguously tell us they were conscious.
Researchers estimate awareness in brain-damaged patients may be as high as 40%. Some people in a vegetative state may have some consciousness but their brain injury left them deaf or incapable of responding.
DEFINITION OF DEATH
Life and death do not overlap, and a person can only be in one or the other at any given time. Death is the permanent cessation of critical functions of the whole organism, and the irreversible cessation of all clinical functions of the entire body.
Can doctors now say you are definitely dead when your heart stops beating, your brain no longer has electrical activity, or you no longer can live without medical equipment, such as a ventilator or life support?
In this new world of technology, the meaning of death requires redefinition, since loss of vital functions can be continued and performed artificially. To define death, we now must identify measurable criteria and develop tests to validate death.
HEART TRANSPLANTATION
Modern medicine can now suspend life and death in a comatose patient. If the brain is partially dead and has a slight ability to function, you may continue to breathe with the aid of a ventilator your organs stay healthy. The decision to pull the plug and face the consequences of choice, are problems families must deal with.
In order to obtain heart organs, the definition of brain death has recently been expanded. A brain-dead patient with working organs can have his organs transplanted to a sick recipient with a failing system. If the brain is dead, machines will support the corpse brain, and this is considered a form of death.
Today many brain-damaged patients in vegetative states have their hearts removed from life support units only seconds after that they are disconnected, and transplanted into other sick patients. It is impossible to transplant a heart successfully after a reversible stoppage. According to cardiac criteria, if the heart is restarted, the person from move the heart was taken, could not have been truly dead.
Is it ethical to remove hearts for transplantation from patients who satisfied the diagnostic criteria of brain death, even though we are convinced they are not really dead?
The appropriate time to observe a patient heart cessation, and before the declaration of death, has not been established. We use a three-minute rule after loss of cardiac function (based on recommendations of two minutes in the critical care literature).
There are dangers in taking hearts from donors before the traditional complete cessation of heart and brain functions that typically define death. Surgeons now wait for confirmation of brain death, to confirm a heart donation, and immediately do the transplantation.
The definition of brain death, requires the complete absence of all functions of the entire brain, despite the retention of essential neurologic functions. Organ donation advocates now argue: “If the patient is permanently unconscious, he is dead !”
With this recent study by Owen, is there justification that a patient still should be diagnosed as dead, if he spontaneously breathes and appears to be in a vegetative state? Evidence has shown that brain dead patients who are supported beyond the acute phase of their illness, (which is rarely done), can survive for many years.
The definitions of death are being changed simply to make hearts available. Before 1968, the lack of a heartbeat and breath were considered definite signs of death. As medicine advanced, we can now keep people alive on respirators and feeding tubes, even if the brain is no longer functioning.
A massive brain lesion, as trauma, intracranial hemorrhage or anoxia, classically causes brain death. Medical science redefined brain death, as a complete absence of brainstem reflexes, no evidence of breathing on one’s own, and no signs of consciousness.
Since the world’s organ supply is dwindling, especially hearts, most organs are taken from patients with brain injuries before they are declared dead and before their bodies are taken off life support.
Until recently, if a doctor recommended switching off life support, intensive care would have to wait, until the patient’s heart stopped beating, brain activity ceased, and the doctor officially declare the patient brain-dead. By that time the organs would be too damaged to be usable.
COMMENTARY
The line between consciousness and unconsciousness now is blurred. The Owen fMRI, is technically intensive and not yet ready for widespread use in hospitals. It also can’t be used on patients who require medical metal apparatus. However once adopted, clinically it will involve brain injured patients in their medical care decisions .
Often doctors and families of brain dead victims don’t have the same view about the end of life, and this affects their decision to donate their loved one’s organs. When observing patients in vegetative states, many wonder whether they are alive or dead. The functional MRI may help solve these problems.
Instead of watching the patient for signs of physical activity, who has entrusted his life to them, current new protocols for heart donation, have resulted in doctors watching the readings on sophisticated equipment and a second hand on the clock, to make sure they wait the right length of time.
The current definition of death requires circulatory, cardiac, death and brain death, and permanent cessation of functioning of the organism as a whole. As organ transplantation has been mainstream and especially lucrative, these protocols have expanded to permit invasive intervention in living organ donors, and changing the tests required to determine that death has truly occurred. In many cases, patients are euthanized so their hearts can be donated.
The recent criteria for brain death is only that there is absence of specific brain reflexes. Functions of the brain, our temperature control, blood pressure, cardiac rate, salt and water balance are not considered. Many patients who are brain dead, still maintain these functions which are frequently active.
The quick pronouncement of death on the basis of cardiac criteria, ends up sacrificing patient care to save another patient on the organ donor waiting list. The fMRI may prevent transplant surgeons from jumping the gun and declare someone hopeless, when they might have the potential to recover at some point in the near future.
All vegetative patients are not what they appear to be. They have cognitive capabilities far beyond what they are appearing to be capable of.
Functional MRIs will help identify residual cognitive function of patients. It will prove useful when there is concern about the accuracy of the diagnosis and whether residual cognitive functions are detected. It should also increase our understanding of disorders of consciousness after severe brain injury.
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Arch Neurol. 2007;64:1098-1102
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