UMEM Educational Pearls

Category: Critical Care

Title: Testing for Brain Death

Keywords: Apnea test, brain death, brain stem death, coma, death, cardiopulmonary death (PubMed Search)

Posted: 1/17/2011 by Haney Mallemat, MD
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Brain death is the permanent absence of cerebral and brainstem functions (coma, absent pupillary reflexes, no spontaneous respiration, etc.). Legally, brain death is equivalent to cardiopulmonary death.

  • Prior to brain death testing, ensure the following:
  • SBP > 100, core temp >36 Celsius, and absent brainstem reflexes.
  • An identified cause of brain death.
  • No metabolic abnormalities or intoxication.
  • CNS insult on imaging.

If brain death is suspected, confirmation is necessary. The apnea test is most commonly used, evaluating for spontaneous breaths when disconnected from the ventilator. If apnea testing is not possible (e.g., ambiguous clinical exam or cardiopulmonary instability) ancillary testing is needed:

  • EEG
  • Evoked potentials
  • Cerebral angiography
  • CT Angiogram
  • MR Angiography
  • Transcranial Doppler
  • Nuclear Medicine 


Wijdicks EF, The diagnosis of brain death. N Engl J Med. 2001 Apr 19;344(16):1215-21.