Certain conditions and drugs may interfere with the making of a diagnosis of brain death in a patient.


Can Result In


isolectric EEG

anticholinergic drugs

fixed pupils


isolectric EEG


isolectric EEG

"locked in" state

absent motor activity

neuromuscular blockers

fixed pupils, absent spontaneous respirations, absent motor activity

ototoxic drugs

absent oculovestibular reflex

posthyperventilation apnea

absent spontaneous respirations

pre-existing eye disease

fixed pupils

pre-existing middle ear disease

absent oculovestibular reflex

sedative-hypnotic agents

isolectric EEG, absent motor activity

traumatic head injury

isolectric EEG

vestibular suppressants

absent oculovestibular reflex

severe facial trauma

make testing brainstem reflexes difficult

sleep apnea or severe COPD

chronic retention to carbon dioxide, making the apnea test more difficult to interpret


A confirmatory test (such as measurement of cerebral perfusion) may be warranted if one or more of these conditions are present.


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