Doctors may have saved a North Carolina woman's life recently by literally putting her body on ice.
Amy Moore, a 38-year-old mother, was all but dead when she collapsed at her workplace on Sept. 14, suffering what's called "sudden cardiac death" -- despite having no pre-existing heart conditions. According to doctors at the University of North Carolina where Moore was treated, she had no pulse for 20 minutes.
Watch "World News with Diane Sawyer" for more on this story tonight on ABC.
"She was in really bad shape. It was very scary, she was unconscious, but she was fighting tremendously," said her husband, Jacob Moore.
Moore was rushed to a local hospital in a race against time.
"When I saw her and her family, I thought that her chance of survival was less than 50 percent," said Dr. Joe Rossi, a cardiologist at the University of North Carolina.
Doctors attempted a daring procedure, essentially freezing Moore's body to buy time until they could get her damaged heart pumping again.
The procedure is called therapeutic hypothermia, and it involves artificially lowering the body's temperature.
Moore was wrapped in an ice-cold blanket and injected with freezing fluids to bring her temperature down to just 93 degrees, well below the body's normal 98.6 degree temperature. Her body was kept in that state for two days.
The cooling put Moore's brain into a dormant state, helping to avoid the brain damage that comes when the heart temporarily stops providing the brain with blood.
The window for such treatments is short. A patient must be cooled within 30 to 60 minutes of sudden cardiac death, but the procedure is available at an increasing number of hospitals across the United States.
The original idea of using hypothermia to help cardiac arrest victims was born out of the clinical observation that children who fell through icy ponds or lakes and become trapped underwater could frequently survive without neurological damage, even in instances when they were under water for up to an hour.
In normal situations, by contrast, there is a very slight chance of survival after loss of circulation for 10 minutes.
Since the appearance of two studies on the use of hypothermia in the setting of cardiac arrest in the New England Journal of Medicine in 2002, clinical centers have been implementing this technique -- and in some academic centers, it has even become a routine procedure over the past two to three years.
Still, debate over which patients benefit from therapeutic hypothermia continues, and definitive guidelines vary across institutions.
What is known is this: when patients suffer cardiac arrest, the lack of circulation results in severe damage to the brain. And the cooling effect offered by therapeutic hypothermia may give many of these patients a better chance of pulling through.
"The real mechanism is unknown, but it is hypothesized that cooling in the setting of cardiac arrest gives the brain time to rest and heal," said Dr. Michael Sayre, chairman of the Emergency Cardiovascular Care committee of the American Heart Association and an associate professor of emergency medicine at Ohio State University.
The cooling could also preserve the brain through a critical window of time during a cardiac arrest when the cells of the brain would normally die off, he said.