Noting that “it appears that Marlise Muñoz has never been declared dead,” Gary Greenberg explains how brain death is determined:
A doctor can’t always determine whether the brain is truly dead. The diagnosis is made the old-fashioned way: by careful observation. A doctor checks to see whether the eyes are responsive to light or touch; she pricks the nailbeds to discern whether the pain registers; she tests muscle reflexes; she determines whether the buildup of carbon dioxide triggers spontaneous breathing if the ventilator is shut off; and she may use an electroencephalograph to detect electrical activity in the brain. (However, even a dead brain may produce some voltage.) If all the findings are negative, then the declaration is made.
Even then, the doctor can be wrong. Patients declared dead have begun to breathe on their own, after the machines were withdrawn; organ donors have shown signs of life, even as their organs were being removed; and, in at least one case, the harvest was aborted and the patient eventually went home, neurologically impaired but decidedly alive. And there are cases, well-known among transplant doctors and ethicists, in which people have taken home “dead bodies” that have gone on to live for long periods. In one case, a three-and-a half-year-old boy whose brain was destroyed by infection was taken home by his mother, who cared for him for twenty years in her basement before he finally died, from cardiac arrest, in 2004. Evidently, the body does not always fall apart in the absence of its maestro.
The Dish 