<prompt> All of the following signs confirm the brain death exceptHypothermiaAbsent corneal reflexDilated fixed pupilsNo heart movements  <response>: A Hypothermia Brain death is present when there is irreversible loss of all brain function, both brain-stem function and cortical hemisphere function. Brain death criteria -- Loss of brainstem function Absent cranial nerve reflexes - Pupillary light reflex; Corneal reflex; Oculo vestibular reflex cold caloric test; No gag reflex Absent respiratory brain stem reflexes is done by Apnea test: Loss of cortical function No spontaneous movement; no response to external stimuli; Irreversibility Brain death is present when there is irreversible loss of brain function criteria ? loss of brainstem function absent cranial nerve reflexes, pupillary light reflex, corneal reflex, oculo vestibular reflex. 