For thousands of years, the term "death" meant the permanentstopping of the heart and breathing. However, when Bjorn Ibsenfrom Denmark invented the artificial respirator in the 1950s,breathing and heartbeat could be continued when people werein a deep coma. This invention and the rise of better medicineand medical care forced doctors to rethink the old definitionof "death." In 1959, French doctors Mollaret and Goulon firstdescribed what is now called "brain death." In 1968, the rulesfor deciding "brain death" were first put in place with guidelinescalled the Harvard criteria. These were developed by anesthesiologistand early bioethicist Henry K. Beecher. Following ChristianBarnard’s first transplant of a human heart in 1967, Beecherwrote that organ donation from those who were "hopelessly unconscious"would be beneficial.
In a study reported in this issue of Neurology®, Greer andco-authors studied this question by looking at the top 50 USneurology and neurosurgery programs. They compared the officialmedical guidelines from these top hospitals against guidelinesused by the American Academy of Neurology (AAN) published in1995 (see the table).
The good news is that doctors in most of these programs closelyfollowed the AAN guidelines in the examination of brain death.All hospitals correctly defined brain death as irreversiblecoma with absent brainstem reflexes (such as reactions of thepupils to light and other "automatic" reflexes). However, manycenters’ policies did not follow AAN guidelines on rulesfor testing. Programs were not the same in the attention theypaid to low body temperature (hypothermia), sedative or paralyticmedicines, or the presence of severe metabolic disorders thatmight confuse the diagnosis of brain death.
Although careful and standardized testing of the absence ofbreathing—called apnea testing—is needed for thediagnosis of brain death, the centers were a bit different inhow they did apnea testing. Programs were also different inthe number of required examinations and the required time betweenthem, the use of extra tests, and in deciding who makes thediagnosis. The best person to make the diagnosis should be atrained and experienced neurologist, but the medical staffingat many US hospitals might make this difficult.
This study is important because it provides facts about currentpractices that can help improve the 13-year-old guidelines fromthe AAN; in addition, the authors mention areas where thereare too many differences between current practices and the AANguidelines. We need to make practices more similar so that doctorscan keep the trust of patients and their families. Also, a definiteassessment of death is needed for organ donation so that organsare taken at the right time.
All of these things together are needed for the successful continuation—andgrowth—of organ donor programs. Finally, studies likethis one also give families better information about potentialoutcomes from coma. By better understanding the future—bothgood and bad—of patients in coma, families can make informedchoices about continuing or stopping life-sustaining therapy.By improving the diagnosis of brain death, doctors can providestrong proof in cases when further treatment would not be helpfulor ethical.
Doctors should make every effort to make the correct diagnosisfor patients in coma. A patient who is brain dead or who willalways be in a "vegetative state" should be correctly diagnosed.Also, doctors should not make a mistake when saying that a patientwill always be in a "vegetative state." A patient who is "vegetative"is in a state of "wakeful unresponsiveness" in which the eyesare open but there is no awareness of self or others. Such patientshave reflex movements, including random eye movements, but areunconscious (Laureys S. Eyes open, brain shut: the vegetativestate. Scientific American 2007;4:32–37).
Here, doctors need to make all efforts to make sure there isno consciousness left and also exclude the diagnosis of a minimallyconscious state (MCS). MCS patients show limited and changingsigns of awareness as evidenced by occasional but inconsistentpurposeful movements such as following a command or speaking.These responses are not simple reflexes. However, MCS patientscannot reliably communicate (spoken or nonspoken) their thoughtsand feelings. We also need to improve our understanding of howthe different types of injury (from trauma, or from lack ofoxygen to the brain) influence how the brain moves from comathrough the vegetative state and onto MCS.
Another diagnosis that should not be missed is that of the locked-insyndrome (LIS). Here patients awaken from their coma, fullyconscious, but are unable to move or speak; they can communicateonly by blinking or moving their eyes. Jean Dominique Bauby(whose book The Diving Bell and the Butterfly just appearedin US theaters) probably was the world’s best-known locked-inpatient. His book and movie are about the importance of doctorsnot missing this diagnosis and how a meaningful life can bemissed through misdiagnosis.
All physicians have an ethical obligation to make correct diagnosesin brain death. We thank Greer and co-authors for pointing theway toward the improvement of these clinical assessments throughcareful study.
Greer DM, Varelas PN, Haque S, Wijdicks EFM. Variability of brain death determination guidelines in leading US neurologic institutions. Neurology 2008;70: 284–289.[Abstract/Free Full Text]
Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death. A definition of irreversible coma. JAMA 1968;205: 337–340.[Abstract/Free Full Text]
Beecher HK. Ethical problems created by the hopelessly unconscious patient. N Engl J Med 1968;278:1425–1430.[Medline]
Fins JJ. Constructing an ethical stereotaxy for severe brain injury: balancing risks, benefits and access. Nat Rev Neurosci 2003;4:323–327.[Medline]
Fins JJ, Schiff ND, Foley KM. Late recovery from the minimally conscious state: ethical and policy implications. Neurology 2007;68:304–307.[Abstract/Free Full Text]
Giacino JT, Ashwal S, Childs N, et al. The minimally conscious state: definition and diagnostic criteria. Neurology 2002;58:349–353.[Abstract/Free Full Text]
Jennett B, Plum F. Persistent vegetative state after brain damage: a syndrome in search of a name. Lancet 1972;1:734–737.[Medline]
Laureys S. Death, unconsciousness and the brain. Nat Rev Neurosci 2005;11:899–909.
Laureys S, Pellas F, Van Eeckhout P, et al. The locked-in syndrome: what is it like to be conscious but paralyzed and voiceless? Prog Brain Res 2005;150:495–511.[Medline]
The Quality Standards Subcommittee of the American Academy of Neurology. Practice parameters for determining brain death in adults (summary statement). Neurology 1995;45:1012–1014.[Free Full Text]
Laureys S. Eyes open, brain shut: the vegetative state. Sci Am 2007;4:32–37.
Top.
THE HISTORY OF BRAIN...
HOW DO PHYSICIANS DECLARE...
