The writer is a science commentator
It is not quite “partial resurrection”, as some have dramatically dubbed it, but the novel technique does involve restarting limited blood circulation in organ donors who have just been declared dead. The procedure, which sustains organs inside the body rather than on external machines, has stirred global interest over the past few years because it can substantially increase the supply of transplantable organs.
But, as the journal Science highlights this month, the practice also has its critics. Doctors, ethicists and lawyers have questioned whether it blurs the line between life and death; breaks US law; flouts a key principle of donation; and, despite safeguards, unwittingly triggers brain activity, perhaps even consciousness.
The continuing debate, which has prompted some in the UK and abroad to sensibly pause work while data is gathered, is oddly reassuring: the history of medicine is filled with innovations such as IVF, vaccination and transplantation that faced opposition on the path to acceptance. Controversy is the price we pay for progress.
Transplantation has been a reliable poster child in that regard, from the first-ever transplant, of a kidney in 1954, to the first transplant of a pig’s heart into a human patient in 2022. Still, a voluntary hiatus in the new technique to assuage swirling concerns may ultimately serve the cause of organ donation, an institution built on public trust.
“The science should never run ahead of the ethics,” insists Marat Slessarev, an intensive care doctor at Western University in Ontario, who is beginning a study in Canada to look for brain activity in dead donors.
In many countries, donated organs come chiefly from patients kept on life support who have already been declared brain-dead. They are called “donors after brain death”.
This newer technique, called thoraco-abdominal normothermic regional perfusion (taNRP, sometimes shortened to NRP), instead starts with donors who are typically unconscious and have no prospect of meaningful recovery, but are not yet brain-dead. With appropriate consent, life support is removed, circulation stops and, after death is confirmed, machines are used to restart limited circulation while the organs such as the heart, liver and kidneys are still in situ. Critically in NRP, surgeons clamp some vessels before restoring circulation, to stop blood reaching the brain.
Opposition, including from the American College of Physicians, has gathered steam since the first NRP heart operations, in the UK, were reported in 2016 (the procedure has since spread to Spain, Belgium, the Netherlands and the US, with a March paper outlining the results of 157 such transplants).
Last year, in the journal Chest, bioethicists argued the technique was “distinctly ethically problematic” because restarting circulation violates US standards for declaring death, which requires the “irreversible cessation of circulatory and respiratory function” and flouts the rule that a death cannot be caused to procure an organ. Plus, taking steps to block blood flow to the brain could be read as implicit recognition that a patient might not be brain-dead, opening the door to legal action. NRP advocates counter that restarting limited circulation does not equal resuscitation.
Stephen Large, consultant cardiothoracic surgeon at the Royal Papworth Hospital in Cambridge, whose team carried out those early pioneering operations but is not involved in organ retrieval, counts himself an advocate but has paused such transplants while studies, including at Papworth, investigate further. That seems wise, if frustrating, given the urgent need for more organs.
The Global Observatory on Donation and Transplantation recorded about 8,400 heart transplants globally in 2021 — but nearly 22,000 people are on waiting lists for one. NRP, Large estimates, could increase the supply of hearts by 30 per cent. He also points out that the procedure can help those wanting to leave a life-saving legacy. “I’d love to see a national programme [of taNRP] . . . to realise the last wish of that particular individual, which is to be a wonderful multi-organ donor,” Large told me.
The science to watch will be studies such as Slessarev’s, looking for neurological signals in NRP donors. The delicate question is whether, if any activity is detected, it could be interpreted as sentience or pain. “Is the patient alive now,” Slessarev asks. “Do we give anaesthetics? We just don’t know.”
This is uncharted territory with so much at stake: a promising new science that cannot only save lives but, along the way, may also help to redefine life itself.