Back from the dead

In recent years, there have been a number of cases in which people have defied death by surviving for hours without oxygen. The cells in our bodies need oxygen to survive; without it they begin to die and brain damage sets in within five minutes. Yet these patients have made a full recovery. What makes them special? David Casarett is a clinician at the University of Pennsylvania and has an interest in this field. He told Georgia Mills the story of a girl who had been submerged under the ice of a frozen river...

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