What is “brain death” and why is cryonics less likely to work for patients declared legally brain dead?
A. It is a myth that “brain death” occurs after only a few minutes without oxygen. In medicine, brain death refers to an irreversible loss of all activity of the entire brain, including brain stem, in a patient being maintained on life support. To formally diagnose “brain death” in a patient who has suffered cardiac death (stopped heart), it is necessary to first restart blood circulation and perform neurological tests many hours later. A diagnosis of brain death cannot be made in absence of blood circulation because the brain cannot reveal its true state unless it has access to a supply of oxygen and nutrients. It’s true that a patient deprived of oxygen at normal body temperature for many minutes, and then revived, will likely be diagnosed as brain dead the next day. But this is not because brain death was acutely caused by the period of time without oxygen. It would be more accurate to say that brain death was caused by resuscitation in absence of adequate technology to stop the inj
