December 3, 1934 - November 25, 1978: Age 43
Elaine Esposito was 6 years old when she was anesthetized for a routine appendectomy in 1941. Somehow her brain was damaged at the time of the operation. Some doctors felt she had incipient encephalitis at the time of the operation; others felt that she had not received enough oxygen during the operation.
Whatever the cause, she never regained consciousness, but lived on in a coma for 37 years. During this time she was sometimes deeply asleep, and at other times in a state of open-eyed unconsciousness. She died finally at the age of 43 in 1978.
Sources: Wikipedia, Ethics of Withdrawal of Life Support Systems