Apnea Testing and Brain Death

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Apnea Testing and Brain Death

• Greg Marchand, MD

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Sample Definition of Brain Death

• Definition of Brain Death varies by State
• California
• An individual who has sustained either (1)
  irreversible cessation of circulatory  and
  respiratory functions, or (2) irreversible
  cessation of all functions of the entire brain,
  including the brainstem, is dead. A determination
  of brain death must be made in accordance with
  accepted medical standards.

Benzel EC, Gross CD, Hadden TA, et al.  The apnea
test for the determination of brain death. J
Neuro-surgery 198971191-194
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Sample Documentation

• The patient must undergo two brain death
  determinations, at least three hours apart, and
  meet all criteria listed below. 
• The two examinations must be performed by
  different licensed physicians the first exam by
  any (including house staff), the second exam only
  by an attending physician not part of the primary
  team (i.e. a neurosurgeon, neurologist or
  internist if the patient is admitted to the
  Trauma Surgery service).
• If the patient meets all criteria for brain death
  on both examinations, this should be noted in the
  medical record at the time of the second  exam.
  This time becomes the time of legal death
  declaration. 

Benzel EC, Gross CD, Hadden TA, et al.  The apnea
test for the determination of brain death. J
Neuro-surgery 198971191-194
4
Sample Brain Death Criteria

• Brain Death Criteria vary by Hospital
• 1.  No spontaneous movements and no response to
  deep painful bilateral stimuli
• 2.  Core temperature 35 C
• 3.  Sedatives, paralytic agents, exogenously
  ingested substances (ETOH, cocaine, heroin)
  withheld for a period
•     sufficient to exclude them as a cause coma.
• 4.  A phenobarbital level laboratory assay.
• 5.  Apnea as determined by the apnea test (see
  below).
• 7.  Absence of all brain stem reflexes.

Benzel EC, Gross CD, Hadden TA, et al.  The apnea
test for the determination of brain death. J
Neuro-surgery 198971191-194
5
Sample Testing Protocol

• 1. Ventilate the patient with FiO2 of 1.0 at a
  rate and tidal volume to achieve eucapnea on
  arterial blood gas determination (pCO2 35 - 45
  torr).
• 2. Keeping the patient on FiO2 of 1.0, set the
  ventilator rate to zero. CPAP may be used for
  this. Inactivate back-up apnea rate (i.e. do not
  allow the ventilator to override apnea).
• 3. Observe patient's chest closely for 10 minutes
  for signs of spontaneous breathing.
• 4. Obtain ABG at the end of the 10 minute period
  if no spontaneous breaths are observed. If
  patient breathes he/she has "passed" the apnea
  test and cannot be considered brain dead.
• 5. If the patient does not breathe, and the 10
  minute ABG pCO2 exceed 55 torr, the patient has
  "failed" the apnea test. If the 10 minute ABG
  pCO2 does not reach 55 torr, repeat the test but
  wait longer than ten minutes (try 15 minutes)
  before obtaining the ABG.
• 6. In patients with underlying COPD and baseline
  CO2 retention, adjust the baseline FiO2 so as to
  bring initial PaO2 into the 60-80 torr range.
• Terminate the apnea test prior to 10 minutes if
  (a) the patient has spontaneous respiratory
  efforts or (b) the patient becomes profoundly
  hypoxic (O2 saturation or (c) the patient becomes hemodynamically
  unstable.

Benzel EC, Gross CD, Hadden TA, et al.  The apnea
test for the determination of brain death. J
Neuro-surgery 198971191-194