Shots - Health Blog
Wed March 28, 2012
A Struggle To Define 'Death' For Organ Donors
A new method of obtaining organs for transplantation is raising a host of ethical questions, including whether the donors are technically "dead."
For decades, organ donation has been guided by something called the "dead donor rule."
"We have this idea that you must be dead first — so before your organs can be removed, we agree that you are dead," said Leslie Whetstine, a bioethicist at Walsh University in Ohio.
That probably sounds pretty obvious. But defining "dead" turns out to be pretty complicated. It turns out, there are two ways to declare someone dead. For decades, the main way has been "brain death."
Brain death is defined an "irreversible cessation of all the functions of the brain, including the brain stem," according to James L. Bernat, a Dartmouth Medical School neurologist who is an expert on the science and ethics of organ procurement.
These are often people who have suffered massive strokes or devastating blows to the head.
But transplant advocates have revived another definition in recent years. It's had several names, including "donation after cardiac death (DCD)" and "donation after circulatory death." It says: It's OK if donors initially may still have some brain activity. But in this case, death requires "an irreversible cessation of circulation and heartbeat and breathing and no intervention will be done to restore it," Bernat said. "So it is permanent."
In these cases, no one will perform CPR or anything else to restore circulation on the patient. A typical case might involve someone who has had a massive heart attack. Doctors and families agree there's no hope and decide it's time to discontinue life support.
But some experts are troubled by this for a variety of reasons. University of Pennsylvania bioethicist Scott Halpern explains the biggest one.
"The problem is, it's not at all clear that donors after circulatory determination of death are truly dead," Halpern said.
Why? Well, part of it is that no one can agree on how long surgeons need to wait to make absolutely sure the heart is not going to start up again on its own. Some transplant centers wait 5 minutes. Others wait only 2 minutes.
Now, if this weren't all complicated and controversial enough, surgeons in Michigan are taking it one step further: They're starting to place possible donors on a heart-lung machine, called ECMO, even before their hearts have stopped beating.
"The beauty is that this can be placed relatively quickly, and the pump can be turned on and it can provide blood to nourish the organs until they can be removed surgically and then transplanted into somebody else," said Jeffrey D. Punch, director of the transplant center at the University of Michigan.
The approach could prevent a lot of organs from being wasted and thus save a lot of lives, Punch said.
But this approach raises a whole new set of questions. For starters, critics like Bernat argue that it doesn't make sense. In this scenario, someone is declared dead based on the fact that he has lost his circulation and will never get it back. Then you turn around and restore circulation.
"When you come in and circulate blood around the body, then suddenly you've broken the rules — so that's a big problem," Bernat said.
Another question is whether restoring circulation might keep the brain alive. To address this issue, the Michigan doctors insert a balloon to block blood from getting to the brain. But blurring the line between life and death like this makes a lot of people uneasy.
"You could say, well, they're almost dead, or they're close to dead or they're dead enough. But I don't know if you could say with absolute certain there's no function there and no function that could be brought back," said Stuart J. Youngner, a Case Western Reserve University bioethicist.
Proponents defend restarting circulation with the ECMO machine. "They are in fact dead," Punch said of the patients, noting that circulation has only been restored with a machine, and no one will try to revive the donors' hearts in any way. Doctors wait 5 minutes after the hearts stop beating to make sure the patients are really gone, he added.
The Michigan doctors say the approach is a blessing. Family members have more time to say goodbye and a chance at getting some solace from their loss.
"They are so pleased that the last act of the person's life on Earth was to donate organs and save other people's lives," Punch said.
Transplant surgeons say the chance to turn a death into an opportunity for life is a godsend.
"It's wonderful. I think it's a miracle of sorts," said surgeon Joseph B. Zwischenberger of the University of Kentucky.
Punch and his colleagues have begun training teams at other hospitals on how to use the technique. They are also planning to try it in the emergency room. That's raising yet more tough questions.