Redefining Death?

Chicago1871 · May 2, 2007

The new science of resuscitation is changing the way doctors think about heart attacks—and death itself.

Consider someone who has just died of a heart attack. His organs are intact, he hasn't lost blood. All that's happened is his heart has stopped beating—the definition of "clinical death"—and his brain has shut down to conserve oxygen. But what has actually died?

As recently as 1993, when Dr. Sherwin Nuland wrote the best seller "How We Die," the conventional answer was that it was his cells that had died. The patient couldn't be revived because the tissues of his brain and heart had suffered irreversible damage from lack of oxygen. This process was understood to begin after just four or five minutes. If the patient doesn't receive cardiopulmonary resuscitation within that time, and if his heart can't be restarted soon thereafter, he is unlikely to recover. That dogma went unquestioned until researchers actually looked at oxygen-starved heart cells under a microscope. What they saw amazed them, according to Dr. Lance Becker, an authority on emergency medicine at the University of Pennsylvania. "After one hour," he says, "we couldn't see evidence the cells had died. We thought we'd done something wrong." In fact, cells cut off from their blood supply died only hours later.

But if the cells are still alive, why can't doctors revive someone who has been dead for an hour? Because once the cells have been without oxygen for more than five minutes, they die when their oxygen supply is resumed. It was that "astounding" discovery, Becker says, that led him to his post as the director of Penn's Center for Resuscitation Science, a newly created research institute operating on one of medicine's newest frontiers: treating the dead.

Biologists are still grappling with the implications of this new view of cell death—not passive extinguishment, like a candle flickering out when you cover it with a glass, but an active biochemical event triggered by "reperfusion," the resumption of oxygen supply. "It looks to us," says Becker, "as if the cellular surveillance mechanism cannot tell the difference between a cancer cell and a cell being reperfused with oxygen. Something throws the switch that makes the cell die."

With this realization came another: that standard emergency-room procedure has it exactly backward. When someone collapses on the street of cardiac arrest, if he's lucky he will receive immediate CPR, maintaining circulation until he can be revived in the hospital. But the rest will have gone 10 or 15 minutes or more without a heartbeat by the time they reach the emergency department. And then what happens? "We give them oxygen," Becker says. "We jolt the heart with the paddles, we pump in epinephrine to force it to beat, so it's taking up more oxygen." Blood-starved heart muscle is suddenly flooded with oxygen, precisely the situation that leads to cell death. Instead, Becker says, we should aim to reduce oxygen uptake, slow metabolism and adjust the blood chemistry for gradual and safe reperfusion.

Researchers are still working out how best to do this. A study at four hospitals, published last year by the University of California, showed a remarkable rate of success in treating sudden cardiac arrest with an approach that involved, among other things, a "cardioplegic" blood infusion to keep the heart in a state of suspended animation....
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Whoa.

soccernutter · May 2, 2007

Chicago1871 said: ↑

Whoa.
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Yeah, that was my comment as well.

bigredfutbol · May 2, 2007

soccernutter said: ↑

Yeah, that was my comment as well.
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Ditto.

wallacegrommit · May 2, 2007

Okay. I'll put off having that heart attack until they figure it all out.

Chris M. · May 2, 2007

That is amazing.

I would assume the next step would be to determine if the brain can be fired up again after an hour or so with no brain damage if they adjust the reintroduction of oxygen.

Matt in the Hat · May 2, 2007

Is this gonna lead to zombies?

Dr Jay · May 2, 2007

Chris M. said: ↑

That is amazing.

I would assume the next step would be to determine if the brain can be fired up again after an hour or so with no brain damage if they adjust the reintroduction of oxygen.
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I am optimistic that it can.

We have evidence of people (especially children) who have "drowned" in very cold water surviving for 15 -20 mins without oxygen, whe then get resuscitated with full recovery.

Reperfusion injury to cells has been know in the laboratory for years but this is the first it is being applied to human disease.

fatbastard · May 2, 2007

Neat stuff.

But the obvious question is .... how will it affect the Ghoul Pool?

daisrael · May 2, 2007

Not much else to say but WOW!

Bob Morocco · May 2, 2007

fatbastard said: ↑

Neat stuff.

But the obvious question is .... how will it affect the Ghoul Pool?
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I'm just glad I got my title before it becomes obsolete.

russ · May 2, 2007

Dennis Miller:

The easiest job in the world is coroner.Surgery on dead people.If everything goes wrong,maybe you get a pulse."Damn,honey,I gained one on the table today."
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Mel Brennan · May 2, 2007

Chicago1871 said: ↑

The new science of resuscitation is changing the way doctors think about heart attacks—and death itself.

Whoa.
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Indeed. Thanks for that; the ramifications are far-reaching.

peledre · May 2, 2007

Massively interesting stuff.

Foosinho · May 3, 2007

You just had to know that future generations of humans would someday look at our electro-shocking people's hearts to get them to beat as wildly crude and reckless.

Just like bloodletting.

Anyway, heavy stuff.

Nick_78 · May 3, 2007

Matt in the Hat said: ↑

Is this gonna lead to zombies?
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Well that's a slippery slope I'm just not willing to slide down, next thing you know, these zombies are going to want to marry each other. I say we cut all funding to this zombie-creating research post haste.