Organ donation after cardiac death
More organ donations possible if brain death donation not the only option
At only 32, Sarah Beth Therien suddenly became unconscious. She was rushed to hospital — and would never wake up.
An unexpected heart arrhythmia had left her on life support. "A machine kept her heart pumping, but we knew she was gone," said Emile Therien, her father.
After a week, Emile Therien and his wife, Beth Therien, made the difficult decision to withdraw life support.
Their daughter had always wanted to donate her organs, but she didn’t meet the brain death criteria required for donation. Her Ottawa family was determined to fulfill her final wish. In 2006, she became the first Canadian in nearly four decades to donate her organs after cardiac death — not brain death. And the decision didn’t go unnoticed.
Six years later in 2012, among the 540 deceased organ donors in Canada nearly 14 per cent donated after cardiac death. Cardiac death donation, also called non-heart-beating donation is now practised in Ontario, British Columbia, Alberta, Quebec, and Nova Scotia.
Canada joins other countries like the United Kingdom, United States, Spain, and the Netherlands, where non-heart-beating donation is more widespread.
Donation guidelines revised
Donation after cardiac death was the only method of deceased organ donation prior to the advent of brain death criteria in the 1960s — when the concept of someone being "brain dead" was first introduced. Because the brain dies before the heart, organs taken after brain death aren't damaged from a lack of blood flow. As a result, donation after brain death replaced cardiac-death donation.
But over the last two decades, organ shortages, improved organ preservation, and public support led to the re-emergence of donation after cardiac death. In Canada, a national forum of transplant experts in 2005 led to the development of new guidelines that paved the way for this type of donation. And made it possible for Sarah Beth Therien to be a donor.
The potential impact is huge. Brain death accounts for only 1.5 per cent of in-hospital deaths. For the majority of patients with non-survivable illness, death occurs as a result of cardiac death after life support is removed.
Donation after cardiac death could increase the number of available organs by 10 to 30 per cent, according to experts. This could mean the difference between life and death for the nearly 4,500 Canadians currently waiting for a transplant, many of whom will die before getting organs.
The most common organs donated after cardiac death are kidneys, followed by livers, lungs, and pancreases.
Regardless of how donation happens, families make the decision to withdraw life support before organ donation is even discussed, says Dr. Sam Shemie, executive medical director of donation at Canadian Blood Services in Montreal. "In most cases, families approach the health-care team asking about donation," he adds.
Donating organs after cardiac death, however, is very different than doing it after brain death.
In brain dead patients, death is declared while they are still on life support. This allows doctors to keep the heart beating until seconds before organ removal — giving families time to mourn.
But because organs quickly deteriorate after the heart stops, donation after cardiac death can be much more traumatic. Life support is withdrawn and once the heart stops beating, there must be a five-minute period of no pulse, blood pressure, and breathing before death is declared.
The waiting period for cardiac death can last minutes to hours, and occasionally days. If the "dying" process takes too long, organs become injured and unusable — before they’re even removed. But if death occurs quickly, doctors immediately wheel the body away to recover organs before the lack of blood flow causes damage — giving families seconds to say "goodbye."
These differences can be heart wrenching, Emile Therien says. "We were worried that her heart might not stop in time," he says. "If her organs hadn’t been used, we would have been quite disappointed." Letting go of his daughter quickly wasn’t easy either, but he had already come to terms with her being "gone" well before cardiac death.
Ethical issues debated
There’s a growing ethical debate in the medical community about cardiac-death donations, according to a study published in Critical Care Medicine in March 2013. Opponents worry that it doesn’t adhere to the "dead donor" rule, which ethically requires donors to be dead before organs are removed. Some argue waiting five minutes after the heart stops doesn’t ensure the patient is dead and the potential for the brain to "come back to life" still exists.
More research is required to determine the exact time at which death is absolute, says Shemie. But studies show that the brain stops working 20 seconds after the heart has stopped in these donors, he says. "Our waiting period of five minutes is extremely cautious."
On the other hand, transplant doctors argued against the dead donor rule in a commentary published in the New England Journal of Medicine in October 2013. They discussed a recent U.S. case where a donor’s family was distraught when their daughter’s organs weren’t used because death took too long to occur. They wished her organs were removed before her heart stopped.
"When death is very near, some patients may want to die in the process of helping others to live, even if that means altering the timing or manner of their death," says Dr. Scott Halpern, lead author and a critical care medicine doctor at the University of Pennsylvania.
Success depends on timing of organ removal
The success rate at which potential donors end up donating organs after cardiac death depends on the organs being removed — kidneys last longer than livers after the heart stops, for instance — how long it takes for the patient to actually die, and the person’s blood pressure and oxygen levels during the dying process, Shemie says.
And organs donated after cardiac death may not always work as well as those donated after brain death.
Higher rates of dysfunction have been seen in livers taken after cardiac death, says Dr. William Wall, director of the multi-organ transplant program at London Health Sciences Centre in Ontario. Kidneys donated after cardiac death have trouble working initially, but "one-year functioning is similar for kidneys taken after cardiac versus brain death," Wall says.
For Emile and Beth Therien, pioneering the process meant a lot. Sarah Beth Therien donated two kidneys and two corneas, changing the lives of four Canadians. Each donor has the potential to save up to eight lives.
"Sarah was able to save other Canadians. Nothing could have made us happier," Emile Therien says.