We agree with Dr. Machado that experienced physicians should determine death by neurological criteria, but also realize that neurologists, neurosurgeons, or both may not be readily available 24 hours a day in all institutions. For this reason, a method should be provided for intensivists to become trained and proficient in this determination.
The AAN has not endorsed any specialty to clinically determine death by brain criteria. We hope that the examination is done by experienced intensivists, neurologists, critical care neurologists, neurosurgeons and pediatricians, and hope that most hospitals involved with organ donation have a neurologist or neurosurgeon on staff.
Hospital practice protocols may or may not follow the AAN guidelines, and it is fair to say that they are in no way obligated to follow them. It is somewhat unsurprising to find differences. What is new is the introduction of criteria more complicated than the AAN guidelines, very similar to the results of the world survey. [2] Why would more be better? There should be a more uniform method of determination of death by brain criteria, at least in the US if not worldwide.
Again the issue of confirmatory tests in brain death determination seems to dominate the discussion in both letters by Dr. Machado and Dr. Lin, but we believe many of these tests are poorly validated. Even a time-honored EEG or cerebral angiogram is not without difficulty in interpretation. The basis for the use of transcranial Doppler (TCD) is primarily from the consensus statement from the task force of the World Federation of Neurology. [8]
The task force establishes TCD criteria for findings consistent with cerebral circulatory arrest, not brain death (although this may be implicit). The consensus opinion states a prerequisite that the patient first fulfill the clinical criteria for brain death, including permanent coma, exclusion of confounding circumstances, and two experienced examinations showing no evidence of cerebral and brainstem function.
Second, it is unclear, although perhaps implicit, as to whether systolic spikes or oscillating flow should be documented intracranially in both the anterior and posterior circulations. Finally, a lack of signal where one was previously seen is acceptable as proof of circulatory arrest, but this raises the question of technique or transmission problems. These features of the consensus statement may make many clinicians hesitant to incorporate TCD routinely in the diagnosis or confirmation of brain death.
The determination of death by brain criteria should remain a systematic, step-by-step, careful and comprehensive clinical evaluation done by a clinician experienced in the assessment. Leapfrogging to an ancillary test may lead to more confusion, more testing, and perhaps even a delay or deferral of organ donation.
Our article dealt with the problem of brain death guidelines in the US as it pertains to adults; the criteria in children may also need to be revisited. [9] Perhaps now is the time to modernize and systematize our approach to brain death determination in both the adult and pediatric populations.
References
8. Ducrocq X, Hassler W, Moritake K et al. Consensus opinion on diagnosis of cerebral circulatory arrest using Doppler-sonography. Task Force Group on cerebral death of the Neurosonology Research Group of the World Federation of Neurology. J Neurol Sci 1998;159:145-150.
9. Report of special task force. Guidelines for the determination of brain death in children. American Academy of Pediatrics Task Force on Brain Death in Children. Pediatrics 1987;80:298-300.
Disclosure: The authors report no conflicts of interest.
We agree with Dr. Machado that experienced physicians should determine death by neurological criteria, but also realize that neurologists, neurosurgeons, or both may not be readily available 24 hours a day in all institutions. For this reason, a method should be provided for intensivists to become trained and proficient in this determination.
The AAN has not endorsed any specialty to clinically determine death by brain criteria. We hope that the examination is done by experienced intensivists, neurologists, critical care neurologists, neurosurgeons and pediatricians, and hope that most hospitals involved with organ donation have a neurologist or neurosurgeon on staff.
Hospital practice protocols may or may not follow the AAN guidelines, and it is fair to say that they are in no way obligated to follow them. It is somewhat unsurprising to find differences. What is new is the introduction of criteria more complicated than the AAN guidelines, very similar to the results of the world survey. [2] Why would more be better? There should be a more uniform method of determination of death by brain criteria, at least in the US if not worldwide.
Again the issue of confirmatory tests in brain death determination seems to dominate the discussion in both letters by Dr. Machado and Dr. Lin, but we believe many of these tests are poorly validated. Even a time-honored EEG or cerebral angiogram is not without difficulty in interpretation. The basis for the use of transcranial Doppler (TCD) is primarily from the consensus statement from the task force of the World Federation of Neurology. [8]
The task force establishes TCD criteria for findings consistent with cerebral circulatory arrest, not brain death (although this may be implicit). The consensus opinion states a prerequisite that the patient first fulfill the clinical criteria for brain death, including permanent coma, exclusion of confounding circumstances, and two experienced examinations showing no evidence of cerebral and brainstem function.
Second, it is unclear, although perhaps implicit, as to whether systolic spikes or oscillating flow should be documented intracranially in both the anterior and posterior circulations. Finally, a lack of signal where one was previously seen is acceptable as proof of circulatory arrest, but this raises the question of technique or transmission problems. These features of the consensus statement may make many clinicians hesitant to incorporate TCD routinely in the diagnosis or confirmation of brain death.
The determination of death by brain criteria should remain a systematic, step-by-step, careful and comprehensive clinical evaluation done by a clinician experienced in the assessment. Leapfrogging to an ancillary test may lead to more confusion, more testing, and perhaps even a delay or deferral of organ donation.
Our article dealt with the problem of brain death guidelines in the US as it pertains to adults; the criteria in children may also need to be revisited. [9] Perhaps now is the time to modernize and systematize our approach to brain death determination in both the adult and pediatric populations.
References
8. Ducrocq X, Hassler W, Moritake K et al. Consensus opinion on diagnosis of cerebral circulatory arrest using Doppler-sonography. Task Force Group on cerebral death of the Neurosonology Research Group of the World Federation of Neurology. J Neurol Sci 1998;159:145-150.
9. Report of special task force. Guidelines for the determination of brain death in children. American Academy of Pediatrics Task Force on Brain Death in Children. Pediatrics 1987;80:298-300.
Disclosure: The authors report no conflicts of interest.