In the New England Journal of Medicine yesterday, doctors from Denver reported on three controversial cases of heart transplantation from newborn infants. These cases are striking for several reasons. They were examples of so-called ‘donation after cardiac death’ (DCD), an increasingly frequent source of organs for transplantation, but done very rarely in newborns. They are controversial because the transplanted organs were hearts that were ‘restarted’ in recipients after they had stopped in the donor. Transplant surgeons waited only a relatively short period after the donor’s heart had stopped (75 seconds) before starting the organ retrieval process. These transplants raise serious questions about the diagnosis and definition of death.
Death is defined by doctors in two ways, either by the ‘irreversible
loss of brain function’ (brain death), or by the ‘irreversible loss of
heart function’ (cardiac death). Although these definitions are framed
in scientific and medical terms, they represent value judgements about
how we care for humans at the end of life. Both definitions have been
revised and framed in the knowledge that they affect the availability
of life-saving organs.
DCD is an option in patients who are on life-support in intensive care,
but who have suffered such severe brain damage that doctors, after
discussion with family, have decided to withdraw life support and let
the patient die. When breathing tubes and machines are taken away the
patient stops breathing, and, sometime later, their heart stops. This
can take a while, in which case the patient’s organs are not able to be
transplanted because they will have been deprived of oxygen for too
long. But if the patient ‘dies’ quickly, their organs may be suitable
for transplant.
Heart transplants after DCD are very unusual. In fact, the very first
successful human heart transplant by Christian Bernard was of this
sort. But in recent years they come largely if not exclusively from
donors who are brain dead. There is a medical reason for this, once the
heart has stopped, the muscle rapidly becomes damaged from lack of
blood flow and then isn’t suitable to be transplanted. But there is
also a philosophical conundrum. The donor is defined as dead because
their heart has irreversibly stopped. But the heart isn’t irreversibly
stopped, because it can be re-started in another body. So if the heart
has been successfully transplanted, the donor wasn’t actually
‘dead’.Doctors have got around this problem by suggesting that
when life support is removed from a patient and their heart has stopped
for more than a few minutes this is “irreversible” because the heart is
not likely to restart by itself , and doctors are not going to
resuscitate the patient because of their severe brain damage. But this
changes the definition of ‘irreversibility’ from being a question of
physical possibility, to one contingent upon choice or the nature of
things in the absence of intervention.
The cases reported this week highlight that our choices about organ
donation and the definition of death represent an attempt to balance
competing values – the value of saving lives through making organs
available, and the value of caring for those who are critically ill and
likely to die. Pushing the boundaries, as these doctors have done, has
resulted in three infants with severe heart problems surviving, who
would almost certainly have died waiting for a heart transplant
otherwise. But reducing the threshold for transplant raises the spectre
of harvesting organs from patients who might otherwise survive.
Some have questioned whether doctors have now gone too far in the
pursuit of new sources of organs for transplant.
However others have argued that DCD is a valuable and important way of
allowing some good to come from tragedy. Birth asphyxia affects 1 to 2
infants per 1000 births. In newborns with devastating brain injury,
such as those reported in the New England Journal, it is widely
accepted that it is permissible to withdraw life support and to let
those infants die. This is not because those infants cannot be kept
alive. (*) However, given their prognosis it is permissible to allow
them to die. For the most severely affected infants death ensues
rapidly and inevitably after life support is withdrawn.
We cannot harm these infants by retrieving their organs, though we could cause harm to other infants if donation is prevented.
Commentators writing in response to the New England Journal article
suggested that in light of these transplants we should consider
revising our definition of death. Severe cortical brain damage might be used to
diagnose ‘higher brain death’. Alternatively others have suggested that
the underlying assumption that only those already ‘dead’ can be organ
donors should be challenged. However the very real limit to such
radical changes is public acceptance and trust in the transplantation
process. If that trust is undermined, the potential increase in donors
might be outweighed by a fall in consent rates by individuals and their
family. There is a need for more thought… and more debate about the
meaning, and management of death.
* If intensive care is continued, such infants will usually start to
breathe on their own, and be able to be weaned from breathing support.
They can have artificial feeding tubes inserted. But they survive long
term with severe spastic quadriplegic cerebral palsy, epilepsy and
profound intellectual disability.
References
Bernat JL. The Boundaries of Organ Donation after Circulatory Death. N
Engl J Med 2008;359:669-71.
Veatch RM. Donating Hearts after Cardiac Death — Reversing the
Irreversible. N Engl J Med 2008;359:672-3.
Truog RD and Miller FG. The Dead Donor Rule and Organ Transplantation.
N Engl J Med 2008;359:674-5.
Curfman GD, Morrissey S, and Drazen JM. Cardiac Transplantation in
Infants. N Engl J Med 2008;359:749-50.
When to declare donors dead. Time 13/8/08
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