Determination of Brain Death
Donn Dexter, MD, FAAN
Douglas T. Miller Symposium
April 29, 2011
Disclosures
• Full time physician at Luther-Midelfort
Mayo Heath System, Eau Claire,
Wisconsin.
• No financial relationships or interests that
pertain to organ donation.
Outline
• What is Brain Death?
• How Do You Declare Brain Death?
– Clinical Evaluation
– Neurologic Evaluation
– Apnea Test
– Ancillary Tests
• Conclusion
Determination of Brain Death
• Uniform Determination of Death Act
•
•
(UDDA).
An individual who has sustained either: 1)
irreversible cessation of circulatory and
respiratory function or 2) irreversible
cessation of all function of the entire brain,
including brain stem, is dead.
A determination of death must be made
with acceptable medical standards.
Determination of Brain Death
• The American Academy of Neurology
(AAN) delineated the medical standards
for brain death in 1995.
• This practice parameter was reviewed in
2010 (Neurology 74, June 8, 2010).
Determination of Brain Death
• Question for the 2010 AAN review: Are
there patients who fulfill the criteria of brain
death who recover brain function?
• In adults, the recovery of brain function has
not been reported after clinical declaration
of brain death using the 1995 AAN brain
death criteria.
Determination of Brain Death
• Determination of Brain Death – 4 Steps
1) Establish irreversible and proximate
cause of coma.
2) Achieve normal core temperature.
3) Achieve normal systolic blood
pressure.
4) Perform neurologic examination.
The Clinical Evaluation
• Establish Irreversible and Proximate Cause
of Coma
– Usually obvious.
– Exclude drugs (including alcohol above
legal limit).
– No recent or persistent neuromuscular
blocking agents (train of 4 twitches to
nerve stimulation).
– No severe electrolyte, acid-base, or
endocrine disturbance (ABGs, lytes, chem
panel).
The Clinical Evaluation (cont.)
• Achieve Normal Core Temperature
– Core body temperature > 36 degrees C.
– Important for apnea test.
– Warming blanket and warmed IV fluids
may be required.
The Clinical Evaluation (cont.)
• Achieve Normal Systolic Blood Pressure
– Neurologic examination usually reliable
with systolic BP > 100 mmHg.
– UW-OPO requires systolic BP > 100
mmHg.
– May require vasopressors to maintain
adequate BP (dopamine and
neosynephrine often preferred).
The Clinical Evaluation (cont.)
• Perform Neurologic Examination
– One examination is sufficient.
– Examiner should be intimately familiar
with brain death criteria.
– Most commonly a critical care specialist,
neurologist, or neurosurgeon.
– Varies by state. Outside WI check with
state statute.
The Neurologic Examination
• Coma
– No evidence of responsiveness.
– No eye opening to noxious stimuli.
– No motor response to noxious stimuli
other than spinally mediated reflexes
(may require expertise to distinguish).
The Neurologic Examination (cont.)
• Absence of Brainstem Reflexes
– No pupillary response to bright light
(typically fixed @ 4-9 mm).
– Absent corneal reflex.
– Absent facial muscle movement to
noxious stimulus.
– Absent pharyngeal and tracheal reflexes
(gag and deep suction).
The Neurologic Examination (cont.)
• Absent Brainstem Reflexes (cont.)
– Absent eye movements to oculocephalic
testing (doll’s eyes test); integrity of
cervical spine must be certain.
– Oculovestibular testing (cold water
calorics) – Head of bed 30 degrees, 50
mL ice water irrigation of each patent
ear canal with 5 minutes observation
and 5 minutes between tests.
The Apnea Test
• Preconditions
– Normothermia.
– Systolic BP > 100 mm Hg.
– Euvolemia (positive fluid balance).
– Eucapnia (PaCO2 35-45 mmHg).
– No evidence for CO2 retention (COPD,
severe obesity, severe OSA).
The Apnea Test (cont.)
• Preoxygenate for 10 minutes to PaO2
>200 mm Hg.
• Reduce ventilation frequency to 10 bpm
and PEEP to 5 cm H2O.
• If pulse oximetry remains > 95%, check
baseline ABG.
• Disconnect ventilator and preserve
oxygenation with 100% O2 @ 6-10 lpm
via catheter through the ET at level of
carina.
The Apnea Test (cont.)
• Watch closely for respiratory movements
(abdominal or chest excursions).
• If no respiratory efforts, draw ABGs at 3-5
minutes and again at 7-10 minutes.
• If arterial PaCO2 is 60 mm Hg or greater
or if >20 mmHg over baseline, the test is
positive.
• If inconclusive, may extend to 10-15
minutes if clinically stable.
The Apnea Test (cont.)
• Abort Apnea Test for:
– Spontaneous respiratory effort.
– Significant cardiac ectopy.
– Pulse oximetry <90%.
– Systolic blood pressure < 90 mmHg.
Ancillary Testing
• EEG, TCD, CTA, MRI/MRA, cerebral
angiography, and nuclear scans have all
been used to confirm brain death.
• Used when standard testing impossible or
inconclusive (i.e. aborted apnea test).
• EEG, cerebral angiography, and nuclear
scan preferred.
Documentation
• Follow checklist closely!
• Time of death is the time PaCO2 reached
target.
• If apnea test aborted, the time of death is
the time ancillary test is interpreted.
Conclusion
• Have a clear and available protocol for the
determination of brain death at your
institution (UW-OPO has a good one).
• Review it regularly; test it formally.
• Follow it closely.