Doctors Change the Way They Think About Death

[swn919]

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?GT1=9951

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© 2007 MSNBC.com

[JPINFV]

Interesting

/University of California represent!

[ERDoc]

I did a quick pubmed search for the paper from UofC but couldn't find it. If anyone happens to come across it, post a link.

[JPINFV]

http://repositories.cdlib.org/cgi/viewcont...text=postprints

Found it. Let me know if the link doesn't work because I'm connected though my school via a VPN right now so I can have journel access.

/Friggin UCLA

//zot zot zot

[Ridryder 911]

Interesting findings. I do believe that we do not fully understand death yet. Now, with this saying, I understand their hypothesis but the difficulty would be correcting the etiology that caused death to begin with )of course in the study most were post op patients). Now, the studies need to be focused on the amount of oxygenation or allowable hypoxia before the cell death occurs.

Of course the numbers were limited and findings were intriguing but just at the tip of the iceberg. At least, this will cause debate and repeated studies.

R/r 911

[chbare]

Very interesting, could lead to exciting new research and the development of interventions.

Take care,

chbare.

[ERDoc]

http://repositories.cdlib.org/cgi/viewcont...text=postprints

Found it. Let me know if the link doesn't work because I'm connected though my school via a VPN right now so I can have journel access.

/Friggin UCLA

//zot zot zot

Thanks for the link. I have to say that after reading over the paper, I'm not impressed. It looks like like some good prelim results for in-hospital arrests. For out of hospital arrests I don't think it will change anything. The results were dismal at best. These pts also need to go to a hospital with a cardiothoracic surgeon and cath lab. Not a pracitical idea for some of the more rural areas. Are we going to put cardiopulmonary bypass machines on the ambulances? In the field there is also the problem with an unwitnessed arrest. All of the pts in the study were witnessed arrests. I really don't see this changing out of hospital resuscitation.

[Ridryder 911]

That's what I thought as well. Also, it appeared that they knew the etiology of the arrest so immediate correction could be made. Although, this maybe promising in that it will peak other studies, it appears to be hyped on headlines with little facts otherwise.

I agree, the by-pass is not even considerable in emergency events.

R/r 911

[chbare]

I still think it could spark some interesting cellular biology research.

Take care,

chbare.