BRAIN DEATH Mohammed Alshurem R2 Neurology resident 2013 July 24 th Emergency lecture series Neurology Half academic Day
Transcript
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Mohammed Alshurem R2 Neurology resident 2013 July 24 th
Emergency lecture series Neurology Half academic Day
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Content 1-Historical context 2-Definition 3-Diagnostic Criteria
4-Ancillary test 5-Organ donation
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Historical context before the 1800s: general medical opinion
focused on the heart as the residence for a persons central and
controlling life force. Late 1800s: Machado and his colleagues did
number of experiments demonstrated situations in which patients
with high intracranial pressure ceased to have respirations but
continued to have beating hearts shortly thereafter Horsley,
Duckworth and Cushing noted that patients with disease states such
as intracerebral hemorrhage and brain tumors that increase
intracranial pressure tended to pass away first from respiratory
failure rather than circulatory arrest.
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mid-1970s: The advent of resuscitative measures such as
electroshock and artificial ventilation, forced the medical
community to reconsider the location of vital principles after the
first electroencephalogram was recorded by Bergerin 1929: Sugar and
Gerard were able to show in cats that an occlusion of a carotid
artery resulted in the complete abolition of electric potentials in
the brain Lfstedt and von Reis described 6 patients with apnea and
absent brainstem reflexes who showed no intracranial blood flow
during cerebral angiography but who did not have subsequent cardiac
arrest until 2 to 26 days afterward
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1959: Mollaret and Goulon coma dpass, meaning a state beyond
coma, 23 ventilated patients in which loss of consciousness, brain
stem reflexes, and spontaneous respirations were associated with
absent encephalographic activity. Wertheimer and Jouvet :
description of ((death of the nervous system)), and criteria to
stopping the ventilator in such cases.
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Definition Death is an irreversible, biological event that
consists of permanent cessation of the critical functions of the
organism as a whole. Brain death implies the permanent absence of
cerebral and brainstem functions.
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Diagnostic Criteria Guidelines Before American Academy of
Neurology(1995-2010): Harvard Criteria (1968) Minnesota Criteria
(1971) United Kingdom Criteria (1976) Presidents Commission
Criteria (1981) Unreceptivity and unresponsivity No spontaneous
movement Establish etiologyUnreceptive and unresponsive coma No
movements or breathing No spontaneous respirations when tested for
a period of 4 min at a time Exclude mimicking conditions Absent
papillary, corneal, oculocephalic, oculovestibular, oropharyngeal
reflexes No reflexesAbsence of brain stem reflexes Absent motor
response Apnea with Pco 2 greater than 60 mm Hg Flat
electroencephalogra m A status in which all the findings above
remain unchanged for at least 12 h Absent brainstem reflexes
Absence of posturing or seizures
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Harvard Criteria (1968) Minnesota Criteria (1971) United
Kingdom Criteria (1976) Presidents Commission Criteria (1981)
Exclusion of hypothermia (below 90F or 32.2C) and central nervous
system depressants Electroencephalogram is not mandatory Apnea with
a Pco 2 target of 50 mm Hg Irreversibility demonstrated by
establishing cause and excluding reversible conditions (sedation,
hypothermia, shock, and neuromuscular blockade) All the above tests
shall be repeated at least 24 hours with no change. Spinal reflexes
have no bearing on the diagnosis of brain death Prolonged
observation in anoxic- ischemic injury Period of observation
determined by clinical judgment Brain death can be pronounced only
if the pathologic process for the above are deemed irreparable with
presently artificial means. Temperature should be 35C Use of
cerebral flow tests when brainstem reflexes are not testable,
sufficient cause cannot be established, or to shorten period of
observation Electroencephalogram is not mandatory
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CMA- 1987 The Clinical diagnosis Of brain death can be made
when all the following criteria have been satisfied. 1.An Etiology
has been established that is capable of causing brain death and
potentially reversible conditions have been excluded 2.The Patient
is in deep coma and shows no response within the cranial nerve
distribution to stimulation of any part of the body. No Movements
such as cerebral seizures, dyski-netic movements, "decorticate" Or
decerebrate posturing arising from the brain are present
3.Brain-stem Reflexes are absent 4.The Patient is apneic when taken
off the respirator for an appropriate time 5.The Conditions listed
above persist when the patient is reassessed after a suitable
interval
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AAN Guidelines 2010 3 clinical finding to declare brain death -
Come (with known irreversible cause) - Absence of brain stem reflex
- Apnea
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Prerequisites (all must be checked) Coma, irreversible and
cause known Neuroimaging explains coma Central nervous system (CNS)
depressant drug effect absent (if indicated toxicology screen; if
barbiturates given, serum level
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Examination (all must be checked) Pupils nonreactive to bright
light Corneal reflex absent Oculocephalic reflex absent (tested
only if C-spine integrity ensured) Oculovestibular reflex absent No
facial movement to noxious stimuli at supraorbital nerve,
temporomandibular joint Gag reflex absent Cough reflex absent to
tracheal suctioning Absence of motor response to noxious stimuli in
all 4 limbs (spinally mediated reflexes are permissible)
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Pupillary reflex
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Corneal reflex
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Vestibulocular reflex Oculocephalic test (dolls eyes)
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Vestibulo-ocular reflex caloric test
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Apnea testing (all must be checked) Patient is hemodynamically
stable (even with the use of vasopressors) Ventilator adjusted to
provide normocarbia (Paco 2 3445 mm Hg) Patient preoxygenated with
100% Fio 2 for 10 minutes to Pao 2 200 mm Hg Patient
well-oxygenated with a positive end-expiratory pressure (PEEP) of 5
cm of water Provide oxygen via a suction catheter to the level of
the carina at 6 L/min or attach T-piece with continuous positive
airway pressure (CPAP) at 10 cm H2O Disconnect ventilator
Spontaneous respirations absent Arterial blood gas drawn at 810
minutes, patient reconnected to ventilator Pco 2 60 mm Hg, or 20 mm
Hg rise from normal baseline value OR: Apnea test aborted
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Ancillary test (only 1 needs to be performed; to be ordered
only if clinical examination cannot be fully performed because of
patient factors, or if apnea testing inconclusive or aborted)
Cerebral angiogram Transcranial Doppler (TCD) Electroencephalogram
(EEG) single-photon emission computed tomography (SPECT)
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When severe facial trauma preventing complete brain stem reflex
testing, preexisting pupillary abnormalities, and sleep apnea or
severe pulmonary disease resulting in chronic retention of carbon
dioxide Not confirmatory or supplemental
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cerebral angiography Invasive Cerebral circulatory arrest is
defined by a lack of opacification of the internal carotid arteries
above the level of the petrous portion or of the vertebral arteries
above the level of the atlanto-occipital junction
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Transcranial Doppler Operator and patient dependent Depend on
ability to obtain reliable signal 10% to 20% of patients will not
have an adequate bone window for ultrasound transmission. when
obtained, TCDs have a specificity of 98% to 100% and a sensitivity
ranging from 88% to 99%.
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EEG simple to perform and provides insight into the cortical
activity of the brain difficult to interpret secondary to artifact
in either a positive or negative direction. sedation and
hypothermia may produce a false-positive result
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(SPECT) hollow skull or empty light bulb sign
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Mimics need to R/O fulminant Guillain-Barre syndrome baclofen
overdose barbiturate overdose delayed vecoronium clearance
hypothermia
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Red Flag normal computed tomography (CT) scan unsupported blood
pressure absence of diabetes insipidus marked heart rate variations
fever or shock marked metabolic acidosis hypothermia lower than 32C
as this is often accidental and reversible marked miosis (opiate or
organophosphate toxicity) myoclonus (lithium or selective serotonin
reuptake inhibitor [SSRI] toxicity) rigidity (SSRI or haloperidol
toxicity) positive urine or serum toxicology
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Organ donation organs that can be transplanted are the kidneys,
heart, lungs, liver, pancreas, and intestines A single donor can
provide organs for 8 people Organ donation in numbers (AS OF 31
DECEMBER 2012) DONORS 120 RECIPIENTS 346 PATIENTS ON THE WAITING
LIST 1250
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Who is a potential organ donor? A potential organ donor is a
mechanically ventilated patient of any age with severe primary
neurological damage., some patients may present with severe
neurological damage that is secondary to an end-stage organ failure
such as pulmonary or cardiac failure. In most cases, these people
are diagnosed with: stroke cerebral anoxia (following
cardiopulmonary arrest, hanging, drowning, poisoning, etc.)
encephalopathy major, severe head trauma
Tissue donation Bone, skin, heart valves, tendons, and corneas
are the main types of tissues used for grafts A single donor can
provide tissues to 15 other people. Hma-Qubec
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References Diagnosis of brain death, G Bryan Young. Uptodate.G
Bryan Young Assessment of Brain Death in the Neurocritical Care
Unit, David Y. Hwang, Neurosurgery Clinics of North AmericaVolume
24, Issue 3, July 2013, Pages 469 482 David Y. Hwang Neurosurgery
Clinics of North AmericaVolume 24, Issue 3 Evidence-based guideline
update:Determining brain death in adults:Report of the Quality
Standards Subcommittee of the American Academy of Neurology. Eelco
F.M. Wijdicks, Panayiotis N. Varelas, Gary S. Gronseth, et al
Neurology 2010;74;1911-1918 http://www.transplantquebec.ca
http://www.hema-quebec.qc.ca
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THANK YOU ANY QUESTION What is the treatment of brain death
?