X-Message-Number: 29472
From: "Mark Plus" <>
Subject: NEWSWEEK: To Treat the Dead
Date: Sun, 29 Apr 2007 09:53:04 -0700

http://www.msnbc.msn.com/id/18368186/site/newsweek/

Doctors Change the Way They Think About Death
The new science of resuscitation is changing the way doctors think about 
heart attacks and death itself.
By Jerry Adler
Newsweek
May 7, 2007 issue - 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. The research takes them deep 
into the machinery of the cell, to the tiny membrane-enclosed structures 
known as mitochondria where cellular fuel is oxidized to provide energy. 
Mitochondria control the process known as apoptosis, the programmed death of 
abnormal cells that is the body's primary defense against cancer. "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. Patients were put on a 
heart-lung bypass machine to maintain circulation to the brain until the 
heart could be safely restarted. The study involved just 34 patients, but 80 
percent of them were discharged from the hospital alive. In one study of 
traditional methods, the figure was about 15 percent.

Becker also endorses hypothermia lowering body temperature from 37 to 33 
degrees Celsius which appears to slow the chemical reactions touched off by 
reperfusion. He has developed an injectable slurry of salt and ice to cool 
the blood quickly that he hopes to make part of the standard 
emergency-response kit. "In an emergency department, you work like mad for 
half an hour on someone whose heart stopped, and finally someone says, 'I 
don't think we're going to get this guy back,' and then you just stop," 
Becker says. The body on the cart is dead, but its trillions of cells are 
all still alive. Becker wants to resolve that paradox in favor of life.

URL: http://www.msnbc.msn.com/id/18368186/site/newsweek/

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