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Brain death
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu),
Dip. Diab.DCA, Dip. Software statistics- Phd
Mahatma Gandhi Medical college and
research institute , puducherry , India
History
• In 1902, Cushing first reported cessation of cerebral
circulation when intracranial pressure exceeded
arterial blood pressure in monkeys
• In 1959, Bertrand and colleagues reported the
maintenance of respiration by mechanical means for 3
days after death of a patient with otitis media who
underwent circulatory collapse
History
• first heart implantation by Barnard in 1967
• ------------------------------------------------------• Irreversible loss of consciousness
• 1976
• Death is defined as the irreversible loss of the
capacity for consciousness, combined with the
irreversible loss of the capacity to breathe.”
Clinical Diagnosis of
Brain Death
Diagnostic Criteria for the Clinical Diagnosis of
Brain Death
• Prerequisites
• absence of clinical brain function when the proximate
cause is known and demonstrably irreversible.
• 1. Clinical or neuroimaging evidence of an acute
central nervous system catastrophe
• 2. Exclusion of complicating medical conditions that
may confound clinical assessment (no severe electrolyte,
acid-base, or endocrine disturbance)
• 3. No drug intoxication or poisoning
• 4. Core temperature ≥ 32°C (90°F)
Brain death
• The three cardinal findings in brain death are
• coma or unresponsiveness,
• absence of brainstem reflexes,
• apnea.
Brain is all omnipotent
• Can we test all ??
• Immune .
• Endocrine etc
The first one
• Coma or unresponsiveness—no cerebral
motor response to pain in all extremities
(nail-bed pressure and supraorbital pressure)
• NO
• Drug intoxication, severe electrolyte, acidbase, or endocrine disturbance,
Brain stem reflexes
• Pupils
• 4 – 9 mm
• No response to bright light
Ocular movement
1. No oculo cephalic reflex (testing only when no
fracture or instability of the cervical spine is
apparent)
ii. No deviation of eyes to irrigation in each ear with
50 mL of cold water
(allow 1 minute after injection and at least 5 minutes
between testing on each side)
oculocephalic reflex
• reflex eye movement that stabilizes images on
the
retina
during
head
movement
by
producing an eye movement in the direction
opposite to head movement, thus preserving
the image on the center of the visual field.
COWS
• Ice cold or warm water or air is irrigated into the external
auditory canal, usually using a syringe.
• The temperature difference between the body and the
injected
water
creates
a
convective
current
in
the endolymph .
• Hot and cold water produce currents in opposite
directions and therefore a horizontal nystagmus in
opposite directions in patients with an intact brainstem:
Facial response
• I . No corneal reflex to touch with a throat swab
ii. No jaw reflex
• iii.
No grimacing to deep pressure on nail bed,
supraorbital ridge, or temporo mandibular joint
Pharyngeal and tracheal reflexes
i. No response after stimulation of the
posterior pharynx with tongue blade
• ii. No cough response to bronchial
suctioning
• Vagus
• Failure of the heart rate to increase by more than 5
beats per minute after 1- 2 mg. of atropine
intravenously. This indicates absent function of the
vagus nerve and nuclei.
Clinical testing
Apnea testing
Apnea testing
• Prerequisites
• i.
•
Core temperature ≥ 36.5°C or 97°F
ii. Systolic blood pressure ≥ 90 mm Hg
• iii. Euvolemia. - +ve fluid balance
• iv. Normal PaCO2. Option: PaCO2≥ 40 mm Hg
• v. Normal PaO2. Option: preoxygenation to obtain
arterial PaO2≥ 200 mm Hg
Apnea testing
•
•
•
•
Connect a pulse oximeter disconnect ventilator.
Deliver 100% O2, 6 L/min, into the trachea
Observe for respiratory movements
8 minutes
• Respiratory attempts + means test negative
• Motor responses (i.e., the Lazarus sign) may occur
spontaneously during apnea testing- spinal origin
Apnea testing
• Measure
arterial
PaO2,
PCO2,
and
pH
after
approximately 8 minutes
• If respiratory movements are absent and arterial
PCO2 is ≥ 60 mm Hg
• (option: 20 mm Hg increase in PCO2 over a baseline
normal PCO2), the apnea test result is positive (i.e., it
supports the diagnosis of brain death).
Problem in between ????
• BP < 90
• Desaturation
• Arrhythmias
• Reconnect & ABG
• PaCO2 > 60 or increase more than 20 from
normal baseline +
• but in between results – indeterminate
After brain death
•
•
•
•
•
•
•
Patients become poikilothermic
Hypothermic
No fever
External heat ?? Use
2 – 24 hours hormones continue to secrete
Immune system
Increased immune mediators, cytokines ?
Organ transplantation success rates
The path
•
•
•
•
•
•
Brain injury
Progress of ischemia
Sudden hypotension ( vagal )
Brainstem death
Unopposed sympathetic (storm)
Can damage myocardium
Young RTA patient with brain death
Cerebral Death: Persistent Vegetative
State
• Stop of the functions of the cerebral cortices.
• Brainstem functions governing the
respiratory centers, autonomic nervous
system, endocrine system, and immune
system, which are vital for maintaining life,
are preserved
• May go for months to years
• That is death ?? Controversial
Brain dead = dead !!
• Central Integrator Theory of the Brain
• In brain death, the body is no more an
integrated organism but a mere and rapidly
disintegrating collection of organs that have
lost forever the capacity of working as a
coordinated whole
Infant organs
• Anencephalics
• Organ donors
• Gernamy OKAYs but still concern about
• Dead donor rule
• Radionucide blood flow and 2 EEG – children
Brain dead mother
• But fetus
• Preserve for weeks
• Tocolytics
• Ethical , moral and legal issues to be sorted
out
Variability in Policies and Practices for
Determining Brain Death
•
•
•
•
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•
•
Law
Guideline
Apnea test
Number of physicians
Observation time
Confirmatory tests
India !!
Confirmatory tests
•
•
•
•
•
•
Cerebral Angiography
Electroencephalography
Transcranial Doppler Ultrasonography
Cerebral Scintigraphy (99mTc-hexametazime)
Evoked Responses
Positron Emission Tomography
Harvard medical school definition
Brain death
• unresponsiveness and lack of receptivity, the
absence of movement and breathing, the
absence of brain-stem reflexes, and coma
whose cause has been identified.
• Withdraw cardio-respiratory support in
accordance with hospital policies, including
those for organ donation
Organ donation -- anaesthetic concerns
• Among the brain dead
• 4 % of deaths are fit to donate
• Out of which 10 % come to our picture
Donor
• A potential donor is any previously healthy
individual who has suffered an irreversible
catastrophic brain injury of known aetiology.
• Exclusion criteria
• old age (greater than 65-70 yr), untreated systemic sepsis,
most extra cranial malignancies, and the presence of
transmissible diseases not amenable to antibiotic therapy
What organs??
• Donor organs may be divided into
• perfusible organs
• (kidneys, liver, heart, lung(s), pancreas, and
bowel)
• Non perfusable organs and tissues (eyes, skin,
bone, heart valves, and dura).
• Maintain perfusion
Rule of 100
• Systolic blood pressure > 100 mmHg
• Urine output > 100 ml. hr
• PaO2 > 100 mmHg
• Haemoglobin > 100 g.
• Blood sugar around 100 mg%
Anaesthetic problems
Other goals
•
•
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•
•
•
•
•
CVP 6- 10 mmHg
pH – 7.35 to 7.45
Na – 130 – 140
K+ -- , calcium, magnesium kept normal
Temperature - > 35.5 – controversial
PaCo2 – normal
Methylprednisolone 15 mg/kg
T3 ( thyroxine)
Anaesthetic concerns
• spinal cords are intact and somatic and visceral
reflexes remain,
• Muscle relaxants are necessary to suppress motor
activity mediated by spinal reflexes.
• Vasodilators usually are employed to suppress
hypertension and tachycardia by noxious stimuli.
• Sedation and analgesia ? !!
Summary
• 1. Establishing the cause of disease
• 2. Excluding certain potentially reversible
syndromes that may produce signs similar to
brain death
• 3. Demonstrating clinical signs of brain
death: coma, brainstem areflexia, and apnea
• Anaesthetic concerns
• Thank you