Transcript Emergency Lecture Series: Introduction to Brain Death and

Emergency Lecture Series:
Brain Death and Organ Donation
Robert Altman, R5
McGill Neurology
August 10th 2011
Outline
• Pre-Test
• Brain death exam in context of “prognostication”
skills
• Definition and standardized exam for brain death
– Canadian + Transplant Quebec guidelines
– AAN guidelines (recently updated 2010)
• Organ donation; Transplant Quebec
• Neuro-otology reinforcement
• Post-test
Pre-Test
1. How many criteria are there to establish NDD?
2. Explain which side the MLF is lesioned if I instil
cold water into the pt’s L ear and you get this
response.
– Is this compatible with NDD?
3. What are the apnea test parameters?
4. What are the 2 “ancillary tests” that should be
used when clinical grounds for NDD cannot be
established? • Transcranial doppler • Tc99HMPAO nuc. med. Scan
•
•
Conventional angio
MRA/I
•
•
EEG
SSEP
AAN 2006
Practice
Parameter
Remember...
Vancouver, 2003
• In all Canadian provinces and territories, the
legal definition of brain death is “according to
accepted medical practice.”
– Practices are largely determined by individual
hospitals or regions.
– Guidelines established by the Canadian Congress
Committee on Brain Death in 1986 and the
Canadian Neurocritical Care Group in 1997
initiated clarification of the criteria, but have not
led to uniform practice.
• “Severe Brain Injury to Neurological
Determination of Death,” held in Vancouver
from 9 to 11 April 2003, was to initiate the
development of a national agreement on the
processes of care, commencing with severe
brain injury and culminating with NDD
Overarching Recommendations
• NDD = Neurological Determination of Death
– Confirmation of NDD = legal time of actual death
• Even if there is intact cardiac functions (assumed this will be
temporary, and non-sustained)
• No clear medical basis for 2 independent exams
– Can be performed by 2 MD’s concurrently
– If performed at different times, a full clinical examination,
including apnea testing, must be performed at each
determination
– No fixed interval of time is recommended for the second
determination, except where age-related criteria apply
NDD (Neurological Determination of
Death)
• Aetiology established that can cause irreversible
death
• No confounders
• Deep coma
– Absence of motor responses to stimuli, no spontaneous or
abnormal movements (dyskinesia, posturing) or seizures
– N.b. spinal reflexes may exist
• Absence of brainstem reflexes
– No spontaneous breathing during apnea test
• Infants (≥30d and <1yr); repeat exam recommended
R/O These Confounders
1. Unresuscitated shock
2. Hypothermia (core temperature <34 °C)
3. Severe metabolic disorder capable of causing a potentially
reversible coma
–
Glucose, E+ (PO4, Ca, Mg), IEM, LFT, creatinine, BUN
•
Should correct any abnormality that could possibly influence
decision
4. Peripheral nerve / muscle or NMJ blockade
5. Drug intoxications
–
ETOH, barbituates, sedatives, hypnotics
•
–
Should calculate 5 ½ lives to clear drug; longer if cooled.
NB therapeutic levels of AED, sedatives or analgesics do not
preclude the diagnosis
Irreversible Cause of Death
• Neurological assessments may be unreliable in
the acute post-resuscitation phase after
cardiorespiratory arrest. In cases of acute
hypoxic-ischemic brain injury, clinical evaluation
for NDD should be delayed for 24 h subsequent
to the cardiorespiratory arrest or an ancillary test
could be performed.
• Core temperature MUST be ≥ 34°C to proceed
with formal testing.
– Central blood, rectal or esophageal–gastric
– Previously was 32.2°C
Brain Death Exam
• Brainstem
– Pupils
• ≥4-9mm, unresponsive to light* (enquire about Rx given)
– Corneals
• Movement of jaw or lids excludes NDD
– Vestibulo-ocular responses
• OCR (Doll’s)
– Caution if trauma
• Cold calorics
– Pharyngeal
• Stimulate posterior pharynx
• Suction the ETT
• Depress larynx, swallow reflex
– Apnea test
Vestibulo-ocular Response
Oculocephalic and caloric response.
©2001 by BMJ Publishing Group Ltd
Bateman D E J Neurol Neurosurg Psychiatry 2001;71:i13-i17
Doll’s Eyes
• Normal response = eyes always gaze
up towards roof
• Rapid, but steady movements and
observe for direction of gaze
– Activates vestibular system
ipsilateral to head thrust (same
principal for HIT)
• Communicates with contralateral
horizontal gaze center (CN VI)
“orchestrating” the action of the eyes
• Simultaneously dampens
contralateral vestibular tone, etc.
Left vestibular
tone
L CN VI (HGC)
Right vestibular
tone
R CN VI (HGC)
Turn to left
+
-
-
+
Turn to right
-
+
+
-
Cold Calorics
• 30° to the horizontal
• Minimum of 50cc of ice cold water into the inner
ear canal
– Ensure no perforated tympanic membrane before
instilling water
– Use kidney basin, prop up beside ear
• Start observing for eye deviation rapidly; eye
movements should be absent for 1 minute
• Minimum of 5 minutes before evaluating
contralateral side
Cold Caloric Testing
Vestibulo-Ocular Reflex (VOR)
Pearl:
COWS mneumonic
implies intact cortex
(frontal eye fields).
If on coma /
sedated, will not get
corrective
nystagmus.
Attenuates
resting state
vestibular tone
Warm Caloric Testing
(Rarely done in neurology...)
Increases
resting state
vestibular tone
Apnea Test
• Temperature ≥34°C, SBP >90mmHg (adults), euvolemia
• Pre-oxygenate with 100% FiO2 for 10-15 min (PaO2
>200mmHg)
• Baseline ABG
– PH 7.35-7.40
– PC02 40+/- 5 mmHg
• Disconnect ventilator
– T-piece with CPAP at 10 CM H20, deliver FiO2 at 10L/min or insert
catheter into ETT and deliver FiO2 at 6L/min (at carina)
• Observe for respiratory efforts x 8-10 min
• Repeat ABG at 8-10 min and reconnect ventilator
– Test + if
• PaCO2 ≥60mmHg and rise in 2mmHg/min (≥ 20mmHg) above baseline
levels and PH ≤7.28
• No respiratory efforts demonstrated
• Stop if HD instability or desaturation occurs
Apnea Test (if lung disease)
• If severe lung disease
– Caution must be exercised in considering the validity
of the apnea test
– If in the physician’s judgment, there is a history
suggestive of chronic respiratory insufficiency and
responsiveness to only supranormal levels of carbon
dioxide, or if the patient is dependent on hypoxic
drive.
– If the physician cannot be sure of the validity of the
apnea test, an ancillary test should be administered.
Ancillary Testing
• The term “ancillary” should be understood to
mean an alternative test to one that
otherwise, for any reason, cannot be
conducted.
– No longer called “confirmatory” or “supplemental”
– Different connotations
• Gold standard = global absence of
intracerebral blood flow (only 2 tests support)
– Cerebral angiography or radio-isotope scan
Accepted Ancillary Test(s)
Normal
Brain Death
Insufficient Ancillary Testing
Special Circumstances
• Children ≥ 1 yr (including adolescents)
– Same criteria
– Mandates a second exam
• No fixed time interval
– Physician qualified with working with critically ill children (i.e, not an adult
neurology resident doing an elective at the MCH)
• 30 days to 1 year old (corrected for GA)
– Minimum clinical criteria = OCR (more reliable due to external auditory canal
anatomy)
– Repeat exam recommended by another physician / at another time (lack of
collective experience and research on brain death in this age group)
– If uncertain or confounders factoring in, extend time interval or perform
ancillary testing
– Specialists with skill and knowledge in management of infants with severe
brain injury
NDD recommendations for term
newborns aged <30d
• Standards apply for all those >36wks gestation*
• NDD is clinical
– Absence of OCR and suck reflex
– Temp (core) ≥ 36°C
• Min time from birth to first determination is 48h
• 2 determinations required, minimum interval 24h
• Ancillary testing:
– Should be performed when any of the minimum clinical criteria
cannot be established or confounding factors remain unresolved
• “specialists with skill and knowledge in the management of
newborns with brain injury and the determination of death
based in neurological criteria.”
Other tidbits
• NDD can be determined (in adults)
– any physician licensed by the college of physicians
and surgeons or licensing authority in that
jurisdiction.
– excludes physicians who are only on an educational
register.
– does not require a particular level of specialty
certification;
– nonspecialists can declare NDD if they have the
requisite skill and knowledge.
Organ Donation
• 3 pronged approach
– Environment
•
•
•
•
•
Caring attitude; be open and honest
Ask if family members around, or if there is a family spokesperson
Take family to private room
Offer pastoral services
Offer phone, tissue, etc.
– Knowledge
•
•
•
•
Assess loved-ones comprehension of the situation
Emphasize irreversibility of brain death
Repeat the information as many times as necessary
Grant enough time to assimilate the new knowledge
– The Question (at a future time-point)
•
•
•
•
Verify wished of deceased (organ donor signature on RAMQ card)
Be attentive to apprehension; answer questions +++
Offer possibility of communication with T-Q
Emphasize possibility of giving the gift of life to another
Approaching the Family
Possibilities of Donation
• <70 yo; any tissues
• Any age; eyes / cornea
– Transplant Québec (24/7)
Tel: 514-286-0600
Web: www.quebec-transplant.qc.ca
• Heart, lungs, pancreas, liver, kidneys, intestines
– Héma Quebec
• Cardiac valves, bone, skin, tendons
– Banque d’yeux
• Cornea
Resources
• http://www.quebec-transplant.qc.ca
• CMAJ: Brain arrest: the neurological
determination of death and organ
donor management in Canada
• AAN 2010 Clinical practice guidelines
on brain death
– Including PowerPoint presentation
Post-Test
1. How many criteria are there to establish NDD? (4)
•
•
•
•
Death by something known to be able to kill you.
No confounders.
Deep coma with absent motor responses; except local spinal reflexes.
Brainstem death: absent corneals, gag, VOR, pupils midposition and areactive, +
apnea test.
2. Explain which side the MLF is lesioned if I instil cold
water into the pt’s L ear and you get this response.
–
Is this compatible with NDD?
3. What are the apnea test parameters?
4. What are the 2 “ancillary tests” that should be used
when clinical grounds for NDD cannot be established?
•
•
•
Transcranial doppler
Conventional angio
MRA/I
•
•
•
Tc99HMPAO nuc. med. scan
EEG
SSEP
Normal Vestibular
Physiology
Medial rectus
Lateral rectus
III
MLF = Medial
Longitudinal
Fasciculus
“HORIZONTAL
GAZE CENTER”
VI
PPRF
Vestibular
nucleus
Vestibular
apparatus
JGH ER, July 2011
• 65M, felt abrutly unwell one evening, then
literally “flung off his couch,” illusion of
spinning around his room.
– a/w nausea and vomiting, no other craniobulbar
symptoms.
• Exam demonstrates a right beating nystagmus
in primary gaze, worsened on R gaze,
dampened on L gaze, but nontheless present...
• Remainder of exam normal (including TOS).
Which vestibule is hypofunctioning?
fast
fast
slow
slow
L Vestibular
Neuronitis
Slow tonic
deviation L
Rules
III
VI
Left FEF
VI
PPRF
1.
Hypofunctioning
implies fast phase
away (vestibular
neuronitis) OR eyes
tonically drift to
impaired side
2.
Hyperfunctioning
(BPPV), fast phase
towards dysfunctional
vestibular apparatus
PPRF
Dampened
R
Vestibular
nucleus
L
Dampened
Vestibular
apparatus
fast
fast
Slow
Slow
R Irritative
phase of
neuritis
Slow tonic
deviation L
III
L FEF
VI
VI
PPRF
PPRF
Irritated
Vestibular
nucleus
R
Irritated
Vestibular
apparatus
Rules
1.
Hyperfunctioning (BPPV), fast
phase towards dysfunctional
vestibular apparatus
L