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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

http://images.google.com/imgres?imgurl=http://telemedicine.orbis.org/data/1/rec_imgs/57_9.jpg&imgrefurl=http://telemedicine.orbis.org/bins/volume_page.asp%3Fcid%3D1-3-4-14&h=115&w=181&sz=8&tbnid=MQ3goRdz9I4J:&tbnh=60&tbnw=94&start=4&prev=/images%3Fq%3D%2522oculocephalic%2522%26hl%3Den%26lr%3D%26sa%3DG

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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

http://images.google.com/imgres?imgurl=http://pedsccm.wustl.edu/All-Net/media/gif/neurogif/trauma/cpscanbd.jpg&imgrefurl=http://pedsccm.wustl.edu/All-Net/english/neurpage/trauma/head-5.htm&h=249&w=538&sz=16&tbnid=oBGKQkhMfkYJ:&tbnh=60&tbnw=129&start=3&prev=/images%3Fq%3D%2522cerebral%2Bperfusion%2Bscan%2522%26hl%3Den%26lr%3D%26sa%3DN

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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