The first half of the talk was on distinguishing between different types of profound brain injuries.
Coma is understood as "eyes-closed unconsciousness." It is rarely permanent, is the most common initial presentation of severe brain injury, and may progress to...
- complete recovery of neurological function
- recovery with some remaining deficit
- the "locked-in" state
- a minimally conscious state
- permanent vegetative state
- brain death
Brain death, however is permanent. This term indicates the irreversible loss of the clinical function of the entire brain. Not only can a brain dead patient not think or be aware, these folks can't even breathe on their own. In other words, it's a state made possible by the technology of mechanical ventilation. Interestingly, it was first postulated in 1959, and criteria to define brain death was first developed in 1968 in order to have grounds for transplanting organs from a person whose heart was still beating.
The vegetative state can be thought of as "eyes-open unconsciousness." It's argued that like brain death, the vegetative state is a result of modern medical science's ability to keep the body alive through various means. In this state, there is a lack of integration between parts of the brain. Because the upper brain does not receive or send information, there is a "dissociation between being awake and being aware." In these patients, however, the brain stem is generally intact, so they breathe on their own, the heart continues to beat of course, and most reflexes should still be intact (e.g., the reflex to swallow when food is pushed to the back of the throat.) Virtually all neurologists agree that patients like Karen Quinlan and Teri Schiavo were in a permanent vegetative state.
Recovery: Too, it may be important how a person entered the permanent vegetative state. Was it due to trauma or due to a metabolic insult to the brain? It should be noted that there are no cases reported in the entire body of medical literature of a person recovering from a permanent vegetative state--caused by anoxic brain injury--after a duration of 2 years.
Finally, there is an additional condition called the locked-in state. In this case, consciousness is preserved, but the person is completely paralyzed except for eye movement and blinking. The Diving Bell and the Butterfly: A Memoir of Life in Death by Jean-Dominique Bauby is a book written by a man in just such a condition. He dictated the book letter by letter with the assistance of an aide. More information can be found here.
Anyway, I hope you find this information helpful. It is certainly just the tip of the iceberg when it comes to thinking of the ethical issues involved in a case like Schiavo's, but it may be useful for thinking more clearly and speaking more intelligently on such things.
By the way, I'd like to credit my source of this information. It comes from a presentation by Robert L. Fine, MD, FACP, Director, Office of Clinical Ethics, Baylor Health Care System, Dallas; Director of Palliative Care, Baylor University Medical Center.
5 comments:
I heard the same talk recently. The speaker is in the same office as my preceptor. What did you think of Schiavo's CT scans?
Jonathan, why didn't you share the simple but profound solution you have to determining whether a person is in a persistent veg. state? Something along the lines of ordering a stat Persistent Vegetative State serum study with antibody titers. Maybe others will give you a better response than the blank stare I gave you at the time. :) - Clay
You can view Schiavo's head CT at the University of Miami website:
http://www.miami.edu/ethics/schiavo/CT%20scan.png
I'm no neuroradiologist, but I see diffuse extreme atrophy and gigantic ventricles representing a massive loss of cortical tissue. My understanding is that this is totally consistent with a persistent vegetative state (PVS), though of course one can't diagnose PVS through head CT. It's a clinical diagnosis.
It's interesting that the "liberal" media actually showed some bias toward the religious right in this case, i.e., editing video footage to show (deceptive) clips of Schiavo apparently conscious and aware, and not showing the head CT.
Again, the ethics of this case are far beyond the scope of this blog. I just wanted to disseminate some helpful info from the scientific end of things.
By the way, who are you anonymous 1? E-mail me...
Thank you, Clay! My "simple yet profound solution" was meant to highlight the irony of this clinical diagnosis of PVS. There is no one "test"; rather, it takes a hands-on physical examination by a physician.
Yay! I'm glad you got to hear Dr. Fine's presenation. I heard that one at the end of June at the CAIL Bioethics, Death, and Law conference. It was one of the best presentations aimed at both lay people (to a degree), and to the medical profession. It was very good, and I must say that I continue to admire Dr. Fine more and more.
and for poster #1, I actually had Dr. Fine as my preceptor after 1st year.
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