Death is the final outcome for 100 percent of patients. But there's growing evidence that revival is possible for at least some patients whose hearts and lungs have stopped working for many minutes, even hours. And brain death - when the brain irreversibly ceases function -- is also proving less open and shut.
For decades, doctors have recorded cases where people immersed in very cold water have been revived after hours have gone by. Normally, brain cells start dying within a few minutes after the heart stops pumping oxygen.