1. No cerebral function: Patient is in a deep coma, unresponsive to stimuli.
2. No brain stem function: No evidence on exam of cranial nerve function; lack of reflexes (papillary, corneal, cold water calorics, Doll’s eyes, gag).
3. No spontaneous breathing: Apnea test.
*Requirements:* Normothermia, no central nervous system (CNS) depressants or neuromuscular blockers in effect
*Suggestions:* Electroencephalogram (EEG), though not legally required; 6-hour observation period prior to performing brain death examination
1. 7 days to 2 months: Two clinical exams, apnea tests, and EEGs at least 48 hours apart
2. 2 months to 1 year: As above, but 24 hours apart
3. Over 1 year: Two clinical exams and apnea tests 12 hours apart