When does life end? A new way to harvest organs divides doctors.
A new method for retrieving hearts from organ donors has sparked a debate about the surprisingly blurry line between life and death in a hospital – and whether there’s a possibility that donors could still experience some vestige of consciousness or pain as their organs are harvested. harvested.
The new method has divided major hospitals in New York City and beyond. It is championed by NYU Langone Health in Manhattan, which says it became the first hospital in the United States to try the new method in 2020. But NewYork-Presbyterian Hospital, which has the city’s largest organ transplant program, rejected the technique after an ethics committee there looked into the issue.
If the method is applied more widely, it will significantly increase the number of hearts available for transplant, saving lives.
The reason for this is that most heart donors currently come from a small category of deaths: donors who have often been declared brain dead after a traumatic incident such as a car accident. But they remain on ventilators — their hearts beating and their blood circulating, bringing oxygen to their organs — until a transplant team restores their organs.
The new technique, transplant surgeons say, significantly expands the potential pool to patients who are comatose but not brain dead, and whose families have withdrawn life support because there is little chance of recovery. After these patients’ hearts stop, they are declared dead. But hearts are almost never recovered from these donors because they are often damaged during the dying process due to lack of oxygen.
Surgeons have found that returning blood flow to the heart repairs the heart to a remarkable extent, making it suitable for transplantation.
But two aspects of the procedure have made some surgeons and bioethicists uneasy.
The first problem, some ethicists and surgeons say, stems from the way death is traditionally defined: the heart has stopped and blood circulation has irreversibly stopped. Because the new procedure involves restarting blood flow, critics say it essentially invalidates the previous declaration of death.
But that can be a minor problem compared to an extra step surgeons take: They use metal clamps to cut off blood flow from the repaired heart to the donor’s head, restricting blood flow to the brain and thus preventing prevent any brain activity from being restored. Some doctors and ethicists say this is a tacit admission that the donor may not be legally dead.
“It’s kind of a creepy thing to do,” said Dr. Q. Eric Thompson, an experienced cardiac surgeon and transplant specialist, during a recent panel discussion about the procedure at the Yale School of Medicine.
Legally, there are two different ways to determine whether someone has died. In addition to circulatory death, there is brain death: when someone whose brain no longer functions at all can also be declared dead while his heart is still beating.
The new group of donors, on the other hand, comes from the first category and is not brain dead. They can still blink when their eyeball is touched. If their breathing tube is removed, they may struggle for breath.
For them, death is not immediate: five or fifty minutes may pass after life support is removed and a doctor declares that circulation has stopped.
NYU Langone has used the new procedure, which uses a cardiopulmonary bypass machine, to repair nearly 30 hearts in patients that would otherwise not have been transplanted, according to Dr. Nader Moazami, a transplant surgeon who oversaw the first procedure at the facility. Nashville’s Vanderbilt Medical Center embraced the procedure, starting shortly after NYU Langone, and has since performed more.
But some medical groups are outright against it. The American College of Physicians has said that the arteries to the brain must be clamped to ensure brain death while restarting circulation seems to violate “the dead donor rule” – a fundamental principle of organ transplantation in the United States to ensure that organ procurement is not the cause of a donor’s death.
Dr. Robert Truog, a bioethicist at Harvard Medical School who appeared at the Yale panel discussion, said the new technique showed promise for expanding the number of available donor hearts. But he believed that proponents minimized the ethical and legal dilemmas.
“I’m a little concerned that there’s a bit of gaslighting going on among some transplant professionals in the public,” said Dr. Truog last month during the panel.
Dr. Moazami, the NYU Langone surgeon, said much of the criticism comes from ethicists who spend little time with patients on organ transplant waiting lists.
“You can sit in your office and worry about the ethics of something, but you have never had to walk into a room and face a patient with a family who is dying, who has been waiting for an organ and who not going there. to get an organ, and that patient is going to die,” said Dr. Moazami in an interview. “If you’ve ever experienced that in your life, you’ll never tell me what I’m doing is unethical.”
The debate over the procedure – also called NRP, for normothermic regional perfusion – echoes previous medical and legal debates that touched on how death should be defined, where to mark the moment that separates death from dying, and what doctors are allowed to do. do in that final phase. minutes.
Some experts even raise the specter of persecution.
“An ambitious prosecutor could convincingly argue that doctors who followed the NRP protocol also intended to irreversible brain functions that had not been permanently stopped, thus ensuring the patient’s death,” two transplant experts – Alexandra Glazier, a lawyer who runs an organ donation network. across New England, and Alexander Capron, a bioethicist and professor at the University of Southern California – wrote in an op-ed last year in the American Journal of Transplantation.
There are currently 103,327 people on the national transplant waiting list and about 17 people die every day while waiting. Most are waiting for a kidney or liver.
Heart transplants are rare: only about 3,500 are performed each year. Every year, about 20 percent of those on the list waiting for a new heart die or are removed from the list because they become too sick.
Scientific advances may one day alleviate the shortage of organs available for transplant. The solution may lie in organs from genetically modified pigs human organs grown in animals. Or maybe organs grown from scratch in a laboratory.
But until then, expanding the number of heart transplants will require the use of donor hearts.
One Massachusetts company, TransMedics, is selling a machine to deliver oxygen-rich blood to the heart outside the body—avoiding the ethical debate. Removed from the donor, the heart goes in what looks like a Tupperware container, through which the blood circulates. But the devices can be expensive to use.
The NHP procedure is cheaper. The team of Dr. Moazami first performed it on January 20, 2020, on a 43-year-old donor suffering from end-stage liver disease.
The buildup of toxins in his body had left him in a coma. With the family’s consent, life support was withdrawn. After five minutes, the man’s breathing became labored. After 14 minutes his heart had stopped. Ten minutes later, Dr.’s team cut. Moazami opened his chest, clamped off the arteries to his brain and began pumping blood through his body using a bypass machine – the same device routinely used in open-heart surgery.
Eventually the heart resumed its beating on its own. After about half an hour, surgeons removed it and then transplanted it.
Dr. Moazami had heard about the procedure through cases in England, where surgeons in Cambridge began trying the procedure in 2015.
Dr. Moazami does not dismiss the ethical concerns of his critics. He noted that new scientific research has raised complex questions about what happens to the brain after death. He points to experiments at Yale that had restored some cellular activity in the brains of dead pigs.
He said it was necessary to clamp the arteries to the brain as a precaution to reduce the possibility, however remote, of sensations or traces of consciousness when the blood circulation in the donor is restarted.
“The brain remains a ‘black box,’” says a group of ethicists and surgeons from NYU Langone, including Dr. Moazami, wrote last year.