Unifying Concepts

Criteria for Brain Death in Adults and Children

Physicians, health care workers, members of the clergy, and laypeople throughout the world have accepted fully that a person is dead when his or her brain is dead.

Clinical Criteria for Brain Death in Adults and Children

  • Coma
  • Absence of motor responses
  • Absence of pupillary responses to light and pupils at midposition with respect to dilatation (4–6 mm)
  • Absence of corneal reflexes
  • Absence of caloric responses
  • Absence of gag reflex
  • Absence of coughing in response to tracheal suctioning
  • Absence of sucking and rooting reflexes
  • Absence of respiratory drive at a PaCO2 that is 60 mm Hg or 20 mm Hg above normal base-line values*
  • Interval between two evaluations, according to patient’s age

Term to 2 mo old, 48 hr
>2 mo to 1 yr old, 24 hr
>1 yr to <18 yr old, 12 hr
»18 yr old, interval optional

  • Confirmatory tests

Term to 2 mo old, 2 confirmatory tests
>2 mo to 1 yr old, 1 confirmatory test
>1 yr to <18 yr old, optional
»18 yr old, optional

*PaCO2 denotes the partial pressure of arterial carbon dioxide.

Confirmatory Testing for a Determination of Brain Death

Cerebral angiography

  • The contrast medium should be injected under high pressure in both anterior and posterior circulation.
  • No intracerebral filling should be detected at the level of entry of the carotid or vertebral artery to the skull.
  • The external carotid circulation should be patent.
  • The filling of the superior longitudinal sinus may be delayed.


  • A minimum of eight scalp electrodes should be used.
  • Interelectrode impedance should be between 100 and 10,000 ohm.
  • The integrity of the entire recording system should be tested.
  • The distance between electrodes should be at least 10 cm.
  • The sensitivity should be increased to at least 2 µV for 30 minutes with inclusion of appropriate calibrations.
  • The high-frequency filter setting should not be set below 30 Hz, and the low-frequency setting should not be above 1 Hz.
  • Electroencephalography should demonstrate a lack of reactivity to intense somatosensory or audiovisual stimuli.

Transcranial Doppler ultrasonography

  • There should be bilateral insonation. The probe should be placed at the temporal bone above the zygomatic arch or the vertebrobasilar arteries through the suboccipital transcranial window.
  • The abnormalities should include a lack of diastolic or reverberating flow and documentation of small systolic peaks in early systole. A finding of a complete absence of flow may not be reliable owing to inadequate transtemporal windows for insonation.

Cerebral scintigraphy (technetium Tc 99m hexametazime)

  • The isotope should be injected within 30 minutes after its reconstitution.
  • A static image of 500,000 counts should be obtained at several time points: immediately, between 30 and 60 minutes later, and at 2 hours.
  • A correct intravenous injection may be confirmed with additional images of the liver demonstrating uptake (optional).




  1. Wijdicks EF. The neurologist and Harvard criteria for brain death. Neurology. 2003 Oct 14;61(7):970-6. [Medline]
  2. Wijdicks EF. The diagnosis of brain death. N Engl J Med. 2001 Apr 19;344(16):1215-21. [Medline]


Created: Jun 9, 2009

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