Forced body cooling known as therapeutic hypothermia has reduced in-hospital deaths among sudden cardiac arrest patients nearly 12 percent between 2001 and 2009, according to a Mayo Clinic study being presented at the upcoming American Academy of Neurology 2012 Annual Meeting in New Orleans.

The goal of therapeutic cooling is slowing the body's metabolism and preventing brain damage or death. It is believed that mild therapeutic hypothermia suppresses harmful chemical reactions in the brain and preserves cells. Two key studies published in 2002 found therapeutic hypothermia more effective for sudden cardiac arrest patients than traditional therapies. Mayo researchers analyzed a database covering more than 1 million patients and found mortality rates among in-hospital sudden cardiac arrest patients dropped from 69.6 percent in 2001 -- the year before the studies appeared -- to 57.8 percent in 2009, the most recent data available.

"Because we reviewed such a large number of cases, we are confident that the reduction in mortality among in-hospital sudden cardiac arrest patients is significant and sustained," says co-author Alejandro Rabinstein, M.D., a Mayo Clinic neurologist. "We continue to seek answers to the questions: Why did this trend develop, and how can we accelerate it," says co-author Jennifer Fugate, D.O.

These measures are important because disease accumulates in the cortex over time, and inflammation in the cortex is a sign the disease has progressed.