[Ideological differences threaten to muddy the definition of death
in the United States — with potentially negative consequences for
clinicians and people awaiting organ transplants.]
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SUNDAY SCIENCE: WHAT DOES ‘BRAIN DEAD’ REALLY MEAN? THE BATTLE
OVER HOW SCIENCE DEFINES THE END OF LIFE  
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Max Kozlov
July 11, 2023
Nature [[link removed]]

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_ Ideological differences threaten to muddy the definition of death
in the United States — with potentially negative consequences for
clinicians and people awaiting organ transplants. _

The concept of brain death is facing its greatest challenge in the
United States in decades., Alexandra Pavlova/Getty

 

Dead in California but alive in New Jersey: that was the status of
13-year-old Jahi McMath after physicians in Oakland, California,
declared her brain dead in 2013, after complications from a
tonsillectomy. Unhappy with the care that their daughter received and
unwilling to remove life support, McMath’s family moved with her to
New Jersey, where the law allowed them to lodge a religious objection
to the declaration of brain death and keep McMath connected to
life-support systems for another four and a half years.

Prompted by such legal discrepancies and a growing number of lawsuits
around the United States, a group of neurologists, physicians, lawyers
and bioethicists is attempting to harmonize state laws surrounding the
determination of death. They say that imprecise language in existing
laws — as well as research done since the laws were passed —
threatens to undermine public confidence in how death is defined
worldwide.

“It doesn’t really make a lot of sense,” says Ariane Lewis, a
neurocritical care clinician at NYU Langone Health in New York City.
“Death is something that should be a set, finite thing. It
shouldn’t be something that’s left up to interpretation.”

Since 2021, a committee in the Uniform Law Commission (ULC), a
non-profit organization in Chicago, Illinois, that drafts model
legislation for states to adopt, has been revising its recommendation
for the legal determination of death. The drafting committee hopes to
clarify the definition of brain death, determine whether consent is
required to test for it, specify how to handle family objections and
provide guidance on how to incorporate future changes to medical
standards. The broader membership of the ULC will offer feedback on
the first draft of the revised law at a meeting on 26 July. After
members vote on it, the text could be ready for state legislatures to
consider by the middle of next year.

But as the ULC revision process has progressed, clinicians who were
once eager to address these issues have become increasingly worried.

Fuelling their fears is a rising tide of political polarization and
mistrust of scientific expertise. Some clinicians following the ULC
discussions say that the idea of brain death itself is facing its
greatest challenge since its conception in the 1960s. The outcome
could have serious implications for intensive care units (ICUs) across
the United States and might affect the availability of vital organs
for transplant. And although few expect the ULC’s recommendations to
erase the idea of brain death, some observers fear that the doubts and
narratives sown throughout the process could have a lasting effect on
state laws and on public perception.

“I thought this would be an upgrade, and it’s completely fallen
apart from that perspective,” says Robert Truog, a bioethicist and
paediatrician at Harvard Medical School in Boston, Massachusetts, who
is not a voting member of the ULC committee, but has watched its
progress closely. “As soon as we talk about the deeper issues, the
profound disagreement of some members of the committee become
apparent, and you reach a standstill.”

REDEFINING DEATH

Current legal definitions around the world generally allow for two
types of death: when heart and respiratory function stop irreversibly,
or when crucial functions of the brain are lost. Historically, these
two have been closely entwined: stop the heart, and the brain is dead
in minutes. Stop the entire brain functioning, and the heart stops
beating. But medical advances in the 1950s, such as modern
ventilators [[link removed]],
meant that the two types of death could be separated.

Such technologies, along with improved methods of measuring brain
function, prompted the formation of a committee at Harvard University
in Cambridge, Massachusetts, in 1968. The members developed a
definition of irreversible coma or brain death
[[link removed]] that
was controversial at the time.

In 1981, prompted by a presidential commission on the topic, the ULC
codified this form of death into a model law called the Uniform
Determination of Death Act (UDDA), stating that a person can be
considered dead when there is an irreversible cessation of circulatory
and respiratory function or of all functions of the entire brain,
including the brainstem. The Harvard committee and the UDDA proved
influential: most countries in the world followed suit with their own
laws adopting brain death.

People who are in a coma, or who have unresponsive wakefulness
syndrome, or locked-in syndrome are not brain dead. Not all functions
of their brains have stopped, and some might be able to breathe
without the assistance of a ventilator, show signs of wakefulness or
have intact reflexes (see ‘A scale of consciousness’).

Source: J. L. Bernat Annu. Rev. Med. 60, 381–392 (2009)

Today, although brain death makes up just 2% of adult deaths and 5%
of childhood deaths in hospitals in the United States
[[link removed]], it tends to garner
outsized attention from the media and in the law. Erin Paquette, a
paediatrician and bioethicist at Northwestern University in Evanston,
Illinois, says that’s because the physical appearance of a person
who is brain dead often doesn’t line up with people’s concept of
death. Hooked up to a ventilator, a person who is brain dead might
look like any other individual in an ICU.

This can make it difficult for clinicians to communicate with family
members about brain death, especially when the law lags behind
scientific understanding. This happened in McMath’s case. Although
she never definitively regained consciousness or the ability to
breathe on her own, she began puberty and had her first menstrual
period — a sign that a small region of her brain called the anterior
hypothalamus, which helps to control the body’s hormones, might have
been active.

This realization prompted her mother to sue the state of California in
a bid to erase the death certificate there because not “all
functions of the entire brain” had ceased as the UDDA dictates.
Using a strict interpretation of the law, McMath’s mother might have
been right, says James Bernat, a neurologist at the Dartmouth Geisel
School of Medicine in Hanover, New Hampshire, even though it wasn’t
a sign that the girl would recover. The anterior hypothalamus, Bernat
says, receives blood through a different supply from the rest of the
brain, so some function might be preserved in a small subset of people
who have been declared brain dead. (McMath’s heart stopped in June
2018, at which point she was issued a second death certificate; her
mother withdrew the lawsuit shortly afterwards.)

LANGUAGE TWEAKS

Clinicians have called for changes to the language of the UDDA, hoping
to clarify which brain areas are relevant to recovery. Other
countries, such as the United Kingdom and India, define brain death
much more narrowly than the United States, focusing not on the entire
brain, but on the brain stem, which is necessary for essential
functions such as breathing, swallowing and maintaining a heartbeat.
The United Kingdom goes one step further by not separating the ways
that death happens: all deaths happen when brainstem function is lost.

Truog supports this simplified system, which Canada adopted in May
[[link removed]].
But Bernat says it’s unlikely that the United States will adopt this
standard: “If the ULC is going to do anything to the UDDA, they want
to just tweak it,” he says. Nevertheless, he hopes that the revised
law will address how to interpret residual activity in areas of the
brain that are not linked to consciousness or breathing.

Facebook

Other language changes are more subtle. Some clinicians have been
calling to amend the law so that it refers to a ‘permanent’ loss
of brain and heart function instead of an ‘irreversible’ one. The
argument is that current tests for death do not evaluate
reversibility, but rather permanence. Irreversibility, clinicians say,
is a much higher standard to meet, and would require them to wait for
hours to prove that they cannot restart heart or brain function. And
even if it were possible to restore some functionality, some have
said it might not be wise or even ethical to do so
[[link removed]].

The need to address the language about irreversibility has been made
more urgent thanks to research by Nenad Sestan, a neuroscientist at
Yale University in New Haven, Connecticut. He and his colleagues
pumped a blood substitute through the bodies of pigs and restored
cellular function in some organs
[[link removed]]1
[[link removed]],
including the brain2
[[link removed]],
hours after the animals were slaughtered. They were careful to note
that although cells might be metabolically active, this does not
translate to organ function. “We might one day be able to reverse
things we used to say were irreversible, and ultimately what we care
about is permanence,” says Alex Capron, a medical ethicist and
specialist in health policy at the University of Southern California
in Los Angeles, who helped to direct national efforts to define death
in the 1980s.

These language discrepancies mean that guidelines put out by
organizations such as the American Academy of Neurology (AAN), in
Minneapolis, Minnesota, outlining what physicians should test for when
declaring brain death don’t line up with the UDDA.

Individual hospitals, too, have their own determination-of-death
policies and procedures that might differ from those put out by the
AAN. Currently, the UDDA states that physicians ought to use
“accepted medical guidelines” as the basis of their determination,
but that leaves room for them to use different medical
organizations’ guidelines, and ones that are outdated.

In 2016, David Greer, a neurologist at Boston Medical Center, and his
colleagues were surprised to find substantial differences when they
analysed nearly 500 hospitals’ policies to see whether they adhered
to the AAN’s guidelines3
[[link removed]].
They found that most clinics did not require someone with neurology
experience to determine brain death, and more than one-quarter
didn’t require physicians to test for conditions that can mimic
brain death, such as abnormally low blood pressure or hypothermia.

New AAN guidelines are coming later this year, says Greer, who
co-authored them. The revision will standardize death determination
between adults and children to make the concept easier for people to
understand, he says. Greer and others are calling for the UDDA to
specify which medical guidelines to rely on and a process by which
states can incorporate newer standards into practice.

ADDED TENSIONS

But some are afraid that the time is not right to update the UDDA.
Lainie Ross, a paediatrician and bioethicist at the University of
Rochester in New York, says that when she heard this process was
opening up, she felt uneasy. “It’s not that I think what we have
is perfect,” she says, “but sometimes, perfect is the enemy of the
good.”

Ross says her fears have been borne out — and many other medical
professionals who spoke to _Nature_ agree that the ULC discussions
so far have not been as productive as they would have liked.

One concern is a lack of scientific expertise. The ULC committee that
will ultimately decide on the final text of the revised UDDA consists
of 15 voting members, all of whom are attorneys, and none of whom has
direct experience treating people with severe brain injury.

One of the commissioners is James Bopp Jr, who serves as the general
counsel for the anti-abortion organization the National Right to Life
Committee in Washington DC. He says that he publicly supported the
UDDA in the 1980s, but has changed his mind in the past few years and
no longer thinks that brain death constitutes biological death. He now
argues that even if a person has no chance of recovery, they still
have rights.

So far, Bopp’s efforts to remove brain death from the UDDA have not
succeeded. But although the concept of brain death will probably
remain in the United States, the ULC might approve bracketed text,
which serves as an optional recommendation for state legislatures as
they consider revising their laws. This bracketed text could include a
clause similar to New Jersey’s current law, allowing people to
object to a diagnosis of brain death for reasons such as religious
beliefs.

Many agree that it’s important to include language to handle
objections and accommodations, but allowing for such opt-out clauses
in the UDDA has split researchers. Truog is in favour of them, adding
that they are the only sure-fire way to stop the deluge of lawsuits
that threatens to undermine public acceptance of brain death. But Ross
says that consistency is paramount, so she would prefer that either no
states have an opt-out clause, or every state has one — to avoid the
situation in which someone is considered alive in one state but dead
in another.

To add to the tension, people who are brain dead represent most
deceased organ donors in the United States (see ‘Organ-donor
dilemma’), meaning that any changes to how death is determined will
also have knock-on effects on the organ waiting list — which
currently stands at more than 100,000 people. The worry is that with
more people refusing to accept a determination of brain death, the
waiting list could grow substantially, and ICUs could be filled with
people who will never recover.

Source: Organ Procurement and Transplantation Network (OPTN)

Truog says that New Jersey has had its opt-out clause for years, and
it has neither massive organ shortages nor ICUs filled with people who
are brain dead. But Capron cautions that expanding opt-outs for
religious reasons to many states would be venturing into uncharted
territory. And signalling that brain death isn’t universally
accepted could “have an effect on people who would not have gone
into it having any doubts”, he says. The logistics of organ
transplantation also become sticky in this scenario: organ-transplant
registries have become more national. Higher opt-out rates could pose
an obstacle if one state’s population is providing fewer organs to
the registry but still requires the same number, Ross says.

EXPLORING OTHER OPTIONS

The outcome of the UDDA revision process is still largely unknown. The
ULC could recommend leaving the 1981 UDDA intact. In that scenario,
individual state legislatures could still vote to revise their laws in
any way that they see fit, but it would be without an explicit
recommendation from the ULC. If drafting continues as planned, the
full ULC will vote on the revised UDDA at its summer 2024 meeting.

Beyond revising the UDDA, there are other, more systemic, ways to
build public trust in the concept of brain death, Paquette says. One
example is more uniform and robust medical training: because
brain-death determinations are relatively infrequent, many neurology
residents in the United States finish their training without
witnessing a single brain-death examination4
[[link removed]].
This can result in less uniformity between clinicians and poor
communication with the family or carers of a person with a devastating
brain injury. Students need more practice in communicating diagnoses
and potential outcomes with the family or carers of a person with a
devastating brain injury, Paquette says.

“It’s helpful to outline what the death based on neurologic
criteria process will look like,” she says. “And it’s important
to acknowledge that what someone is seeing might not match up with
their notion of death.”

_Nature_ 619, 240-242 (2023)

_doi: [link removed]

References

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Andrijevic, D. T. _et al._ _Nature_ 608, 405–412 (2022).

Article [[link removed]] PubMed
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Scholar
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Vrselja, Z. _et al._ _Nature_ 568, 336–342 (2019).

Article [[link removed]] PubMed
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Scholar
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*
Greer, D. M. _et al._ _JAMA Neurol._ 73, 213–218 (2016).

Article [[link removed]] PubMed
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Scholar
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*
Biel, S. & Durrant, J. _Curr. Treat. Options Neurol._ 22, 12 (2020).

Article [[link removed]] Google Scholar
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_MAX KOZLOV is a science journalist at Nature whose work has also
appeared in The Atlantic, Quanta Magazine, Science, The Scientist, St.
Louis Post-Dispatch, Behavioral Scientist, and The Public’s Radio._

_NATURE is a weekly international journal publishing the finest
peer-reviewed research in all fields of science and technology on the
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interpretation of topical and coming trends affecting science,
scientists and the wider public._

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Second, to ensure that the results of science are rapidly disseminated
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significance for knowledge, culture and daily life. Nature's original
mission statement was published for the first time on 11 November
1869._

_About the Editors
Like the other Nature titles, Nature has no external editorial board.
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PHOTOSYNTHESIS IS NEARLY 100% EFFICIENT. A QUANTUM EXPERIMENT SHOWS
WHY
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All biological systems are wildly disordered. Yet somehow, that
disorder enables plant photosynthesis to be nearly 100% efficient.
ETHAN SIEGEL
Starts With A Bang
July 11, 2023

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