2012 brain death
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BRAIN DEATH
Pediatric Critical Care Medicine
Emory University
Childrens Healthcare of Atlanta
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Background Before the 1960s, donation after cardiac death (DCD) was the
general approach to organ donation
1968, an ad hoc committee at Harvard Medical School
proposed a neurologic based death definition, which replaced
DCD
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Background 1980, with modifications, by the Presidents Commission for
the Study of Ethical Problems in Medicine & Biomedical
Research, as a recommendation for state legislature & court
The brain death standard was also employed in the model
legislation known as the Uniform Determination of Death Act,
which has been enacted by a large number of jurisdictions &
the standard has been endorsed by the influential American
Bar Association
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Background Even though there has been legal acceptance of the concept of
brain death, there is a lack of a standardized approach
No national brain death law exists
State law & statutes may restrict the determination of brain
death
Reasons for revising guidelines
Allow physicians to pronounce brain death in pediatric patients in a
more precise and orderly manner
Appropriate documentation
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Brain Death An individual who has sustained either
Irreversible cessation of circulatory & respiratory functions
Irreversible cessation of all functions of the entire brain, including the
brainstem, is dead
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The Examinationhuman brain Cerebrum: memory, consciousness & higher mental function
Cerebellum: controls various muscle functions
Brain stem consisting of the midbrain, pons & medulla, whichextends downwards to become the spinal cord
Controls respiration & various basic reflexes (e.g., swallow & gag)
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Coma Deep coma
Non responsive to most external stimuli
At most, such patients may have a dysfunctional cerebrum but, by
virtue of the brain stem remaining intact, are capable of spontaneousbreathing & heartbeat
PVS: persistent vegetative state
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Organ function
Heart
Needs O2to survive & w/o O2will stop beating
Not controlled by the brain but it is autonomous
Breathing Controlled by vagus nerve, located in the brain stem
Main stimulant is increase in CO2in the blood
Causes the diaphragm & chest muscles to expand
Spontaneous breathing can not occur after brain stem death
With artificial ventilation, the heart may continue to beat for a
period of time after brain stem death
Time lag between brain death & circulatory death is ~2-10
days
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Initial requirements
Clinical or radiographic evidence of an acute catastrophic
cerebral event c/w dx of brain death
Exclusion of conditions that confound clinical evidence (i.e.
metabolic) Confirmation of absence of drug intoxication or poisoning
Including barbituratds, NMB;s
Core body temp >35oC
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Term18 yrs of age Determination of brain death by neurologic examination
should be performed in the setting of normal age-appropriate
physiological parameters
Corrected hypotension, metabolic disturbances, recent administration
of neuromuscular blockaded, or any drug intoxication
Placement of an arterial line is recommended for close
monitoring of BP & PaCO2
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Hypothermia & Brain Death An adjunctive therapy for acute brain injury
Reduces cerebral metabolic activity
Hypothermia is known to depress cerebral activity
May lead to a false diagnosis of brain death
Adequately re-warm with rec. 12 hrs of normal temperature prior to
performing brain death exam
A core body temperature of >35oC should be achieved prior to
doing brain death exam Previous guidelines stated that the patient should not be significantly
hypothermic but no definition was provided
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Drugs Long acting or continuous infusions of sedative agents should
be discontinued
When available levels should be obtained & documented to be
in a low to mid therapeutic range
If a neuromuscular blocking agent has been used, confirmation
of its clearance should be established
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Observation Period General consensus was the younger the child the longer the
waiting period
If ancillary studies supported the diagnosis of brain death, the
observation period could be shortened
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Observation Period 2011 Guidelines
Examinations should be performed by 2 separate attendings
Both apnea tests may be performed by the same physician
Recommends:
37 weeks up to 30 days: 24 hours
>30 days18 yrs: 12 hours
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It is reasonable to defer neurologic examination to determine
brain death for >24 hrs if dictated by clinical judgment
After cardiopulmonary arrest
If apnea testing cannot be performed
If patient is not stable enough to perform certain parts of the
exam, ancillary testing may be used to assist in the diagnosis
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Ancillary Studies Four vessel cerebral angiography is the gold standard for
determining the absence of CBF
EEG & radionuclide CBF are the most widely used methods
Radionuclide CBF can be used in patients with high dose
barbiturate therapy
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Ancillary Studies Ancillary studies are not required and should not be used as a
substitute to the clinical exam
They must be used when
Components of the exam or apnea test cannot be completed safely
Uncertainty about the results
Medication effect may be present
Reduce the inter-examination observation period
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Basic exam 1 - Pain
Cerebral motor response to pain
Supra-orbital ridge, the nail beds, trapezius
Motor responses may occur spontaneously during apnea testing (spinal
reflexes)
Spinal reflex responses occur more often in young
If patient had NMB, then confirm clearance with train-of-four
Spinal arcs are intact!
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Basic exam 2 - Pupils
Round, oval or irregularly shaped
Midsize 94-6 mm0, but may be totally dilated
Absent pupillary light reflex
Although drugs can influence pupillary size, the light reflex remainsintact only in the absence of brain death
IV atropine does not markedly affect response
Paralytics do not affect pupillary size
Topical administration of drugs and eye trauma may influence pupillary
size and reactivity
Pre-existing ocular anatomic abnormalities may also confound
pupillary assessment in brain death
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Basic exam 3Eye movement
Oculocephalic reflex = dolls eyes
Vestibulo-ocular = cold caloric test
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Dolls eyes
Oculocephalic reflex
Rapidly turn the head90 on both sides Normal response = deviation of the eyes to the opposite side of head
turning
Brain death = oculocephalic reflexes are absent (no Dolls eyes) = no
eye movement in response to head movement
Not Barbie, but old fashioned type dolls
Painted vs. wooden eyes in porcelain heads
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Dolls eyes
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Cold calorics
Elevate the HOB 30
Irrigate both tympanic membranes with iced water
Observed pt for 1 min after each ear irrigation, with a 5 min wait
between testing of the other ear Facial trauma involving the auditory canal & petrous bone can also
inhibit these reflexes
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Cold calorics
Nystagmusboth eyes slow toward cold, fast to midline
Not comatose
Both eyes tonically deviate toward cold water
Comawith intact brainstem Movement only of eye on side of stimulus
Internuclear ophthalmoplegia
Suggests brainstem structural lesion
No eye movement Brainstem injury/death
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Basic exam 4
Facial sensory & motor responses
Corneal reflexes are absent in brain death
Corneal reflexestested by using a cotton-tipped swab
Grimacing in response to pain can be tested by applying deep pressureto the nail beds, supra-orbital ridge, TMJ, or swab in nose
Severe facial trauma can inhibit interpretation of facial brain stem
reflexes
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Basic exam 5
Pharyngeal & tracheal responses Both gag & cough reflexes are absent in pts w/brain death
Gag reflex can be evaluated by stimulating the posterior pharynx w/a
tongue blade, but the results can be difficult to evaluate in orally
intubated patients
Cough reflex can be tested by using ETT suctioning, past end of ETT
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Apnea Testing Should be performed with each test unless there is a clinical
contraindication
If cannot be performed an ancillary test should be performed to assist
PaCO2>60 mmHg has been used as the threshold to stimulate
ventilatory efforts
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Apnea Testing Technique:
Normalization of pH & PaCO2
Maintenance of core temperature > 35oC degrees
Normalization of BPage appropriate
Pre-oxygenation for 5-10 min with 100% oxygen via connectin to t-
piece or self-inflating bag
Apneic oxygenation for ~6 min
PaCO2should rise >20 mmHg above baseline & >60 mmHg
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Ancillary Studies Four vessel cerebral angiography is the gold standard for
determining the absence of CBF
EEG & radionuclide CBF are the most widely used methods
Cerebral blood flow = perfusion scan
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Cerebral perfusion scan
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Common misconceptions
Since there is a heartbeat, he is alive
Brain dead pts have permanently lost the capacity to think, be aware of
self or surroundings, experience, or communicate w/others
Hes in a coma
Reinforce that they are dead
With rehab/time hell get better
Irreversible, dead brain cells do not regrow
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How to make it clear
Say dead, not brain dead
Say artificial or mechanical ventilation, not life support
Time of death = neurologic determination
NOT when ventilator removed NOT when heart beat ceases
Do not say kept alive for organ donation
Do not talk to the pt as if hes still alive
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Ancillary Studies If EEG shows electrical activity or CBF study shows evidence
of flow, patient cannot be pronounced dead
Patient should be medically treated until brain death can be
established solely on clinical examination & apnea testing
If repeat ancillary testing is performed, a waiting period fo 24
hours should be observed
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Ancillary Studies If an ancillary study, in conjunction with the first neurologic
examination, supports the diagnosis of brain death, the inter-
examination observation period can be shortened
The second test can be performed at any time thereafter for
children of all ages
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2011 Strong Evidence Highfurther research is very unlikely to change our
confidence in the estimate of effect
When an ancillary study is used because there are inherent
examination limitations, then components of the examination
done initially should be completed & documented
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2011 Strong Evidence Highfurther research is very unlikely to change our
confidence in the estimate of effect
When an ancillary study is used because there are inherent
examination limitations, then components of the examination
done initially should be completed & documented
Determination of brain death in neonates, infants & children
relies on a clinical diagnosis that is based on the absence of
neurologic function with a known irreversible cause of coma.Coma & apnea must coexist to diagnose brain death.
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2011 Strong Evidence Prerequisites for initiating a brain death evaluation:
Hypotension, hypothermia, & metabolic disturbances that could affect
the neurologic examination must be corrected before the examination
for brain death
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2011 Strong Evidence Declaration of death:
Death is declared after confirmation & completion of the second
clinical examination & apnea test
When ancillary studies are used, documentation of components from
the second clinical examination that can be completed must remain
consistent with brain death. All aspects of the clinical examination
including the apnea test, or ancillary studies must be appropriately
documented
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2011 Strong Evidence The clinical examination should be carried out by experienced
clinicians who are familiar with infants & children & have
specific training in neuro-critical care
The examination should be performed by different attending
physicians involved in the care of the child
The apnea test may be performed by the same physician,
preferably the attending physician who is managing ventilator
care of the childlow evidence but strong recommendation
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2011 Moderate Evidence Prerequisites for initiating a brain death examination
Sedatives, analgesics, NMB & anti-convulsant agents should be
discontinued for a reasonable time period based on elimination half-life
of the pharmacologic agent to ensure they do not affect the neurologicexamination
Knowledge of the total amount of each agent (mg/kg) administered since
hospital admission may provide useful information concerning the risk of
continued medication effects
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2011 Moderate Evidence Prerequisites for initiating a brain death examination
Sedatives, analgesics, NMB & anti-convulsant agents should be
discontinued for a reasonable time period based on elimination half-life
of the pharmacologic agent to ensure they do not affect the neurologicexamination
Knowledge of the total amount of each agent (mg/kg) administered since
hospital admission may provide useful information concerning the risk of
continued medication effects
Blood or plasma levels to confirm high or supra-therapeutic levels ofanti-convulsant with sedative effects should be obtained (if available)
& repeated as needed or until the levels are in the low to mid-
therapeutic range
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2011 Moderate Evidence The diagnosis of brain death based on neurologic exam alone
should not be made if supra-therapeutic or high therapeutic
levels of sedative agents are present
When levels are in the low or in the min-therapeutic range, medicationeffects sufficient to affect the result of the neurologic exam are unlikely
If uncertainty remains, an ancillary study should be performed
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2011 Moderate Evidence Assessment of neurologic function may be unreliable
immediately after cardiopulmonary resuscitation or other
severe acute brain injuries & evaluation for brain death should
be deferred for 24-48 hrs if there are concerns orinconsistencies in the exam
Number of exams, examiners & observation periods
2 exams including apnea testing with each exam separated by an
observation period are required