Neur. Examination

Confirms coma, brainstem areflexia, and apnea.

• No sign of arousal or awareness

• No response (e.g., eye-opening, eye movement) to noxious stimulus

• Absence of pupillary light reflex: nonreactive, midsized, or dilated pupils

• Absence of ocular movements tested via:

  • Vestibuloocular reflex (VOR)

  • Oculocephalic maneuver: a brainstem test in which the examiner rapidly rotates the patient's head from side to side or up and down and observes their eyes (while holding the eyelids open)

    • Negative test (abnormal response, indicating brainstem injury): The patient's eyes will not move in their sockets and the gaze moves with the movement of the head.

    • Positive test (normal response, indicating intact brainstem function): The patient's eyes will move in their sockets in the opposite direction to the movement of the head, maintaining the gaze fixed on the same point in space.

    • Should only be performed if cervical spine integrity has been ensured.

• Absence of corneal reflex

• Absence of gag reflex and cough reflex (tested via tracheal suctioning or a tongue blade)

• No motor reaction to noxious stimulation of facial muscles (tested via deep pressure to the supraorbital ridge and temporomandibular joint)

• An essential part of the evaluation of brain death, proving the absence of brainstem respiratory control system reflexes

• Performed after all criteria for brain death have been met

• The following must be ensured for safe and accurate apnea testing:

  • Normotension

  • Normothermia

  • Euvolemia

  • Eucapnia

  • No evidence of hypoxia or CO2 retention

• After preoxygenation with 100% oxygen, the patient is disconnected from the ventilator and observed for evidence of respiratory drive (such as gasps or chest movement).

• After 8–10 minutes, an arterial blood gas reading is obtained.

• pCO2 > 60 mm Hg and/or decreased pH < 7.30 when mechanical ventilation assistance is removed signifies an absence of respiratory drive, and the apnea test is considered positive.

• If the test is inconclusive, the procedure can be repeated for a longer period of time if the patient is hemodynamically stable.

• These tests are only necessary if clinical examination and/or apnea testing are inconclusive or the patient is < 1 year of age.

• Suitable ancillary brain death tests are:

  • Electroencephalography (EEG)

  • Cerebral angiography

  • Radionucleotide scans (HMPAO SPECT)

  • Transcranial Doppler ultrasonography

• Conditions that may mimic brain death

  • Organophosphate intoxication

  • Guillain-Barré syndrome

  • High cervical spinal cord injury

• Conditions that may mimic brain function

  • Spontaneous or reflexive complex motor activity (e.g., repetitive leg movements)

  • Cyclical constriction and dilatation in light-fixed pupils

  • False triggering of ventilator detection system for spontaneous breathing drive

• If a patient has been declared to have brain death, no consent is needed to withdraw life-sustaining therapy.

• The patient's family should be informed that the patient is being assessed for brain death as soon as the evaluation has started.

• The patient's family should be given a reasonable amount of time to visit the patient and accept the diagnosis before discontinuation of life-sustaining treatment.

• If the patient's family disagrees with a diagnosis of brain death:

  • Discuss the family members' concerns with them; express empathy and respect for their position and provide additional information to eliminate any misunderstandings regarding the diagnosis.

  • Involving a hospital ethical committee may be helpful in resolving disagreements.

  • If the disagreement stems from religious or cultural beliefs, consider involving chaplains and/or local cultural leaders in the discussion.

If spontaneous breathing is present, the medulla is intact. If the corneal reflex is present, the pons is intact. If the pupillary light reflex is present, the midbrain is intact.