in order for a person to be declared "whole-brain" dead, they must satisfy criteria including a lack of response to stimulation, lack of reflexes, and lack of spontaneous respiration when tested on two occasions, apart.

The answer is "24 hours".

Everybody recognizes what "brain dead" means: a man whose brain never again works is brain dead. The term is utilized so habitually and in such huge numbers of various settings that we ought not be astounded that 66% of individuals mistakenly trust that somebody who is brain dead isn't lawfully dead, and the greater part trust that a sluggish patient is brain dead. Such errors and disarrays make it simple to appreciate why there is still a decent arrangement of discussion about the connection between assurance of death and organ donation.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )