Brain death is irreversible unconsciousness with complete loss of brain function, including the brain stem, although the heartbeat may continue. Absence of apparent brain function is not insufficient, it must be accompanied by evidence of irreversibility. Brain death may be used as a sole basis for the determination that a person has died
In the United States, diagnosing brain death us guided by the Uniform Determination of Death Act, which sets the standards for using brain-based criteria to diagnose death. However, it does not specify the elements to be used in making the diagnosis. Both individual experts and organizations, such as the American Academy of Neurology, have published guidelines for brain death protocols.