Doctors explain the 'persistent vegetative state'
Terri Schiavo, the brain-damaged Florida woman whose husband and parents are battling over whether to let her die or keep her alive, exists in the rare and paradoxical "persistent vegetative state," where neurologists can find a patient to be at once unconscious but alert.
With her cerebral cortex apparently destroyed, Schiavo is almost certainly unable to return to a state of awareness -- that is, knowing who she is and where she exists in time and place.
These are traits, like the faculty of speech, governed by the cerebral cortex, which, doctors say, has died in Schiavo's case.
But she is decidedly not brain-dead.
Her brain stem -- a more primitive and hardy core of nerve tissue that controls her breathing and cycles of wakefulness -- is very much alive, as evidenced by her ability to breath without a respirator and her open eyes, which can appear to track a moving object.
Defining the differences in these states of being is the work of neurologists such as Dr. Wade Smith, director of the Neurocritical Care Unit at the UCSF Medical Center. He regularly teaches a course on the subject to young medical students, many of whom are entering a lifetime of counseling families on difficult choices of life and death in the midst of trauma and tragedy.
Without her feeding tube or water, and barring legal intervention, Schiavo probably has less than two weeks to live. But in a vegetative state, does she feel hunger, thirst or pain? "As a neurologist, I would say no," said Smith.
A person who is unconscious will feel no more hunger or pain than a patient who has undergone general anesthesia. The awareness functions of the higher brain are no longer a factor. "It is why anesthesia works," Smith said.
But people in a persistent vegetative state will nonetheless react to a "painful" stimulus in a reflexive manner. Pinch, and they will flinch.
A patient in a persistent vegetative state would never be considered a candidate to donate an organ; hearts, lungs, livers and kidneys can be harvested only from the brain-dead.
Neurologists are armed with a long list of descriptors for the varying states of mental being. At one end is brain death, and at the other is consciousness. But in between, the medical meanings can sow confusion:
Because Schiavo's eyes can open, she is, by definition, alert.
With eyes that open and close in accord with cycles of sleep, it even could be argued that a person in a persistent vegetative state can be simultaneously unconscious and awake. A brain scan, however, would show no activity that we normally associate with wakefulness.
A person in a vegetative state is defined as one who is arousable -- which means merely a reflexive response to a stimulus -- but unaware. It is not necessary to wake up to be aroused. If a vegetative state exists for six weeks to three months, it is deemed a "persistent" vegetative state.
A person in a persistent vegetative state is not in a coma. A person in a coma is unconscious, and unable to be aroused.
There is a similar distinction defining stupor. A person in a stupor shows some response to stimulation but will easily slip back into a state where he or she cannot be aroused.
Sleep, strictly defined, is a state of unconsciousness from which a person can be aroused. But there is another halfway state -- somnolence -- where a person can wake up enough to carry a brief conversation before falling back into sleep.
The strange limbo of people in vegetative states poses a dilemma to those who must make life-and-death decisions in the state of full awareness.
"If two physicians sit down and examine a person like Terri Schiavo, there can be a disagreement," said Smith.
In the medical literature, there are no cases of someone recovering from what is defined as clinical brain death, but there are five published cases of "recovery of some sentient function" among patients who were diagnosed as being in a persistent vegetative state.
Typically, the decisions that are made about the future of people in vegetative states are made by family members.
"Most of these discussions never leave the intensive care unit," Smith said. "That's the way it should be."
This is your view?
""Now let's say you're wrong (unknowingly). but you get your way and the tube is pulled out. BUT Terri is really semi conscience and can be somewhat rehabilitated. And Terri all along is feeling this tremendous pang of starvation. And she dies a painful death. We can't undo death."" from my post.