より生き生きとした臓器を移植することが乳児の命を救うことになるが、一方で臓器提供者の生命の価値が損なわれる。脳死より心停止後、心循環死cardiocirculatory death (DCD)の宣言後の移植というプロトコール。両親が蘇生処置をしないと選択した場合に心停止後１分30秒後に臓器が摘出される。臓器提供の件数が劇的に増加する可能性がある。
Are Organ-Donating Infants Really 'Dead'?
When Does An Infant's Life End?
Doctors Debate When Organs Can Be Donated
By JOSEPH BROWNSTEIN
ABC News Medical Unit Aug. 14, 2008
Doctors are locked in debate over a new approach to infant heart transplants, in which surgeons remove the organs of babies before they are declared brain dead.
A heart transplant protocol in infants is an issue of contention for many doctors and ethicists.
Some say the approach saves lives by providing more viable organs to babies who have a chance at survival. But others say the practice devalues one life to try and save another.
The protocol, known as transplantation after declaration of cardiocirculatory death (DCD), allows for the transfer of organs following the stoppage of the heart, rather than brain death. In cases where the parents choose not to resuscitate, their infant's organs could be removed about a minute-and-a-half after the heart stops beating.
This type of organ transplant has previously been done with adult donors, and a new study looking at the use of the method in three infants determined that the transplants were just as successful as those taken from infant donors following brain death.
"There's potential to dramatically increase the opportunities for organ donation," said Dr. Mark Boucek, a pediatric heart surgeon at Joe DiMaggio Children's Hospital in Hollywood, Fla., who took part in the study while at Denver Children's Hospital.
"What we have shown… is that the organs are essentially equal between children who donated organs following brain death to children who donated organs following cardiocirculatory death," he said.
The results are published in this week's issue of the New England Journal of Medicine.
According to Boucek, applying the heart death standard to infants comes as a way of overcoming two problems he has faced over the years: the number of infants who die while awaiting a heart transplant and the number of infants who die with parents wanting to donate their infants' organs but cannot.
During the course of the study, Boucek said that 12 parents volunteered their child's organs, though in nine cases they could not be matched to an infant in need of a heart transplant.
Crossing the Line?
But what some doctors see as a lifesaving procedure is raising concern among other physicians who fear doctors will be more focused on preserving an infant's organs than doing everything possible to save its life.
"I understand the concerns people have... but this is a misguided endeavor," said Dr. Michael Grodin, a professor of health law, bioethics and human rights at the Boston University School of Public Health.
He said this procedure -- whether done in children or adults -- crosses a line in terms of when organs can be taken.
"That line is clear and bright, and I think it needs to stay that way," Grodin said.
Indeed, doctors disagree on the exact point when a patient can be declared dead, revealing that the question of when life ends is as debatable as when it begins.
One central concern is the heart itself. Though the organ could technically be restarted in the donor infant, it is not. But once the donor is declared dead, it is transplanted into the organ recipient and then restarted.
"The fact that the hearts could be restarted in other infants whose prognoses were better does not suggest that the hearts should have been kept going in the bodies of the original donors," said R. Alta Charo, a professor of law and bioethics at the University of Wisconsin Law School.
"In the donor bodies, the continued pumping of the heart was futile, given the scope of damage elsewhere. But in the recipients, the pumping hearts could lead to salvaged lives," she said.
But Grodin disagreed.
"To my standard, the person is not dead," he said. "Taking the heart of somebody [when there's a] question of whether they're dead or not is a serious concern."
In this case, he said, the patient clearly does not meet the necessary criteria of having the heart irreversibly stopped.
"If you're going to take out the heart, obviously the heart starts up again or you couldn't do the transplant, so it's clearly not irreversible," he said.
Grodin also raised the issue of public perception.
"I think that we need to be very concerned about the public's sensibility and sensitivity," he said.
But Boucek said that those concerns can be eliminated by transparency in the process of deciding when and how to donate a dying infant's organs.
He said the parents' prerogative would determine whether the organs can be donated, and only after death was declared by one medical team would another come to transfer the donated organs.
"I think the public knows when death occurs," he said.
'Bending the Rules' a Concern
One concern, raised by Dr. John Lantos, a bioethicist and pediatrician at the University of Chicago, was the lack of a clear protocol to determine when further treatment is futile.
Although he does not find this method of declaring an infant dead before preparing for organ donation ethically problematic, "the problem will arise, as it creates a temptation to bend the standards of futility in order to increase the supply of donors," he said.
Those concerns were echoed by Dr. Steven LeFrak, director of the humanities program in medicine at the Washington University School of Medicine.
"While it sounds very erudite for the authors to refer to withdrawing 'futile' care in their population, what exactly this means is neither defined by them nor is there a generally accepted meaning of this term in medical or medical ethics circles," he said.
"As a result of these problems, this paper is more disturbing than groundbreaking. Perhaps that is because in fact the ground it breaks, the elephant in the room if you will, is the elephant of taking vital organs from living patients so that others may live."
But others counter that not taking steps to preserve organs that would otherwise perish is taking away lives.
"Once it is determined that it will be acceptable for a family to have artificial life support discontinued, not using viable organs wastes precious life-saving resources," said Rosamond Rhodes, director of bioethics education at Mount Sinai School of Medicine. "Using the organs to preserve life has to be ethically better than wasting them, particularly when it costs the lives of other babies."
And as Dr. Vivian Tellis, former director of the transplant program at Montefiore Medical Center in New York, explains, donating the organs might help relieve some of the mental burden from an unfortunate situation, when the family is faced with the death of a child.
"At this painful time for a family, when they make a decision to halt artificial means of support in a child, it can often be an act of kindness to offer the family a chance of helping another child, and so get some solace in an otherwise unbearable circumstance."
NEMJ Volume 359:709-714 August 14, 2008 Number 7
Pediatric Heart Transplantation after Declaration of Cardiocirculatory Death
Mark M. Boucek, M.D., Christine Mashburn, B.S.N., Susan M. Dunn, M.B.A., Rebecca Frizell, B.S.N., Leah Edwards, Ph.D., Biagio Pietra, M.D., David Campbell, M.D., for the Denver Children's Pediatric Heart Transplant Team
In three infants awaiting orthotopic cardiac transplantation, transplantation was successfully performed with the use of organs from donors who had died from cardiocirculatory causes. The three recipients had blood group O and were in the highest-risk waiting-list category. The mean age of donors was 3.7 days, and the mean time to death after withdrawal from life support was 18.3 minutes. The 6-month survival rate was 100% for the 3 transplant recipients and 84% for 17 control infants who received transplants procured through standard organ donation. The mean number of rejection episodes among the three infants during the first 6 months after surgery was 0.3 per patient, as compared with 0.4 per patient among the controls. Echocardiographic measures of ventricular size and function at 6 months were similar among the three infants and the controls (left ventricular shortening fraction, 43.6% and 44.9%, respectively; P=0.73). No late deaths (within 3.5 years) have occurred in the three infants, and they have had functional and immunologic outcomes similar to those of controls. Mortality while awaiting a transplant is an order of magnitude higher in infants than in adults, and donors who died from cardiocirculatory causes offer an opportunity to decrease this waiting-list mortality.
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