The Determination of Brain Death

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The Determination ofBrain Death

• James Zisfein, M.D.
• Chief, Division of Neurology
• Lincoln Hospital, Bronx, NY

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Brain death the early years

• 1950's ACLS and ventilators saved lives
• But there were also unanticipated outcomes
• Physicians saw things they never saw before
• Clinicians saw patients in a state "beyond coma"
• EEGers saw electrocerebral silence
• Pathologists saw the "respirator brain"
• 1960's term "brain death" comes into use
• 1968 Harvard Criteria for brain death
• Loss of animation, brainstem reflexes, and
  respiration
• Electrocerebral silence
• Persistence of the condition for 24 hours

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Published guidelines

• Harvard Criteria (1968)
• President's Commission Criteria (1981)
• American Academy of Pediatrics (1987)
• American Academy of Neurology (1995, 2010)
• This presentation is based on the AAN 2010
  guideline
• New York State Department of Health (2005)
• NYSDOH is aware of the AAN 2010 update and is
  revising its guideline to conform with AAN
• All of these guidelines are 100 specific
• Despite aggressive treatment, a patient who is
  found to be brain dead never regains any brain
  functions

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Definition of brain death

• Brain death is the irreversible loss of all brain
  functions
• "Functions" are clinically ascertainable
• Animation and respiration are brain functions
• Generation of electrical activity, cerebral blood
  circulation, and metabolism are not brain
  functions
• A person who is brain dead is dead according to
  standards of medical practice and the law in all
  US jurisdictions
• This is not optional
• However, reasonable accommodations can be made to
  support the family in case of religious or moral
  objections
• The time of death is the time that this
  determination is made (usually at the conclusion
  of an apnea test)
• It is not sometime later when the heart stops

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The diagnosis of brain death in 5 easy steps

• The cause of brain failure is irreversible.
• The patient is unresponsive.
• Brainstem reflexes are absent.
• An apnea test shows no breathing.
• Laboratory tests are not required unless the
  clinical diagnosis is uncertain.
• Note the guidelines are different for diagnosis
  of brain death in infants under 1 year of age. 

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1. The cause of brain failure is irreversible

• Most brain deaths occur from
• Severe brain trauma
• Massive stroke (usually hemorrhage)
• Prolonged cardiac arrest
• Sufficient time has elapsed to insure
  irreversibility
• Post-cardiac arrest, 6 hours is a reasonable
  interval
• Absence of cerebral blood flow (on a CBF test)
  also documents an irreversible process.

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2. The patient is unresponsive

• We're talking here about cerebral
  unresponsiveness.
• Grimacing and other cranial-nerve responses are
  absent (except for CN XI). 
• Spinal reflexes, e.g. spinal withdrawal, can be
  present.
• Less common spinal movements include
• Fragments of decerebrate posturing (including
  neck extension)
• The undulating toe sign
• Lazarus sign

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3. Brainstem reflexes are absent

• Pupillary light reflex
• Pupils should be mid-position or large
• Vestibulo-ocular reflex (eye movements)
• Doll's eyes and ice-water calorics
• Corneal reflex
• Gag and cough reflex
• Response to suctioning

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4. An apnea test shows no breathing

• Prerequisites absence of respiratory depressants
  (CNS or peripheral), hypotension (SBPlt100), or
  hypothermia (lt36ºC). 
• If ODN or family has not yet been notified,
  please do so now!
• Remove ventilator for at least 10 minutes while
  giving O2 by tracheal cannula. Observe closely
  for breathing. Monitor BP and O2 saturation
  continuously.
• The apnea test confirms brain death if the
  end-of-test PaCO2 is 60 mmHg (or, 20 mmHg above
  pre-test PaCO2).
• If the apnea test cannot be completed, repeat it
  with better patient preparation, or do a cerebral
  blood flow test.

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5. Laboratory tests

• Are not required unless the clinical diagnosis of
  brain death is uncertain.
• The most commonly performed tests are serum
  chemistry and toxicology and CT scan of the
  brain.
• Please put laboratory findings in clinical
  context! 
• Abnormal chemistry or toxicology does not
  invalidate a diagnosis of brain death unless the
  clinical diagnosis is uncertain.
• Presence of an intoxicant is relevant only if the
  quantity present would cause intoxication
• EEG is of very limited value for diagnosis of
  brain death, however it is mentioned in some
  pediatric brain death protocols.

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5. Laboratory tests (continued)

• Perform a cerebral blood flow study (catheter
  angiogram, CTA, MRA, radionuclide study,
  transcranial doppler) when
• cranial nerve examination is inhibited by
  peripheral lesions
• the apnea test is invalidated by central or
  peripheral respiratory depressant drugs (you
  still do the apnea test)
• the apnea test cannot be completed due to
  hypotension or hypoxia (do as much of the apnea
  test as can be done safely)
• the brain failure is not clearly due to an
  irreversible process
• in infants under the age of 1 year
• gt95 of brain death evaluations do not require a
  CBF study

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One exam or two?

• Prior to 2010, brain death guidelines specified
  that the brain death exam had to be performed
  twice
• AAN (1995) suggested 6 hour interval between
  exams
• There was never any evidence supporting this!
• There are no reports of recovery after a properly
  performed brain death exam shows no brain
  functions
• Lustbader et al. (2011) 2nd exam unnecessary on
  1300 brain death evaluations, also 24-hour delay
  in diagnosis
• AAN 2010 single exam is sufficient if performed
  by qualified examiner "several hours" after
  incident event
• NYSDOH does not disagree and will be updating
  state guidelines

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Guidelines for infants lt1 year of age

• Below age 1 year, the observation period should
  be 24 hours, and a confirmatory test should be
  performed.
• Below age 2 months, the observation period should
  be 48 hours.
• Below age 1 week (and in premature infants), the
  diagnosis of brain death may be unreliable.
• Everyone agrees these guidelines for infants are
  excessively conservative.

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"Clinical triggers" for brain death

• Suspect brain death when a patient with severe
  brain injury (e.g., from trauma, stroke, or
  anoxia)
• Is unresponsive
• Has pupils that do not react to light
• Requires a ventilator for breathing
• Do not assume that "triggered" breaths are
  initiated by patient respiratory activity

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When you suspect brain death

• 1. Document your findings.
• You don't have to be a brain death expert to
  document that the pupils and corneals are
  nonreactive, the eyes don't move, there is no
  response to suctioning, and there are no
  spontaneous breaths.
• 2. Obtain consultation from a designated brain
  death expert.
• Requirements for privileging vary by institution.
  Experts do not necessarily have to be
  neurologists or neurosurgeons.
• 3. Contact the patient's family or significant
  other (if known).
• Or, contact hospital administration to help find
  the patient's family. 
• 4. Contact the NY Organ Donor Network
  1-800-GIFT-4-NY
• You must do this even if the patient will not be
  an organ donor.

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References

• Wijdicks E.F.M, et al. Evidence-based guideline
  update Determining brain death in adults Report
  of the quality standards subcommittee of the
  American Academy of Neurology. Neurology 2010
  741911-1918.
• Lustbader D, et al. Second brain death
  examination may negatively affect organ donation.
  Neurology 2011 761-6.
• New York State Department of Health Guidelines
  for determining brain death, December 2005.
  http//www.health.state.ny.us/professionals/doctor
  s/guidelines/determination_of_brain_death/docs/det
  ermination_of_brain_death.pdf