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07/18/2017

The Prognosis for Whole Brain Death is…

Recent court proceedings bring the case of Jahi McMath back into the bioethical news. As you will recall, she had medical complications following a surgical procedure in 2013 and was declared brain dead. The family argued for continued life support, which the hospital denied (since she met the criteria for whole brain death). After much legal wrangling, she was transferred to New Jersey, where she remains alive on ventilator and nutritional support. This case has been reviewed in this blog (here and here). Professor Thaddeus Pope has followed this case from a medicolegalethical standpoint on his Medical Futility Blog, which is generally where I keep up with the case. His catalogue of the legal proceedings is complete, and while I disagree with many of his bioethical positions, I appreciate his rational discussion of those issues. For the remainder of this blog, I wish to focus upon the issue of brain death in the case of Jahi McMath and specifically our ability to accurately determine it.

No one, and as far as I can tell I mean absolutely no one, denies that Jahi met the criteria for whole brain death by late 2013. Her EEG was isoelectric (flatline – no brain electrical activity), radioisotope cranial blood flow studies showed no cortical blood flow (which normally results in cell ischemia, and, if not immediately corrected, brain cell death), brainstem auditory evoked responses (BAERs) were absent (usually indicating future inability to receive auditory input even if there were an otherwise healthy brain ready to receive that input) and somatosensory evoked potentials (SSEPs) were absent above the neck (usually indicating inability to receive sensory input from the body). As a result, she met the criteria for whole brain death in California and was issued a death certificate. Since that declaration, she has shown signs of entering puberty (which requires a minimally functioning portion of the brain called the hypothalamus), her heart rate has been noted to change when she hears her mother’s voice (which should not be possible given her BAER results) and she has moved her right arm to verbal command (an act that would require the ability to receive the auditory input, left hemisphere cortical brain processing of that input, signal transfer within the left hemisphere of the brain to the motor area that controls the right arm, and finally signal transfer down through the brainstem to the portion of the spinal cord that controls the right arm). If any of those are true, Jahi McMath fails to satisfy the criteria for whole brain death. Here is the testimony of Dr D.Alan Shewmon, emeritus professor of pediatric neurology at UCLA and an expert in pediatric brain death. His 26-page testimony provides an excellent discussion of the problems of determining whole brain death, particularly in the case of Jahi McMath.

The problem of potential reversibility after a determination of whole brain death hits home professionally for me. I have cared for patients in an inpatient rehabilitation hospital setting who suffered severe head injuries, as well as consulted on several more who never made it our rehabilitation hospital because of brain death. This included assisting in the discussion of whether to discontinue ventilator, nutrition and hydration support following a proper determination of whole brain death. And, while I think similar discussions are reasonable in individuals sustaining injuries leaving them in a persistent vegetative state (PVS, i.e. having brain function that only acts reflexively without awareness or capability for any cognition, perhaps a better description of Jahi McMath’s current status), no such discussion should happen until brain recovery has reached its maximal endpoint. With whole brain death, those discussions can happen immediately because that endpoint has been reached. Dead brains, by definition, do not recover.

Until now?

The initial determination of whole brain death in Jahi McMath appeared proper.

If the reports of her responsiveness are true, Jahi McMath clearly no longer meets the criterion for whole brain death. The very fact that she has remained alive over three years after the determination of whole brain death argues against whole brain death. Artificial life support has advanced but not to the degree that we can mimic all of the routine vegetative functions controlled by the brain necessary to keep the body alive. It is “easier” to keep an individual in PVS alive because the brain is still doing a large part of its bodily maintenance/regulation work.

At the very least, even if none of the above observations of Jahi McMath are true, the prognosis for whole brain death, while still very, very, very poor, is no longer zero.

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