Brain death diagnosis

Report
Technical Assistance for Alignment in Organ Donation- EuropeAid/131052/D/SER/TR
Key Points
in Brain Death Diagnosis
Clinical aspects and Confirmation
Francesco Procaccio
ISS – CNT - Rome
Neuro Intensive Care Unit
University City Hospital, Verona - Italy
What is Brain Death?
Total Brain Infarct
2
BD Definition
Brain Death is the irreversible loss of
capacity for consciousness combined
with the irreversible loss of all
brainstem functions including the
capacity to breathe.
The Canadian Neurocritical Care Group,
1999
Certainty of death: Irreversibility
Brain Death or Brain Dying?
Death is a process
Neurological functions
must have ceased
irreversibly
Karnice-Karnicki, 1896
F Procaccio 2012
(Brain) Death
“Irreversible loss of all
cerebral functions”
Brainstem
death
6
Why
Brain death is the only death ?
Pathophysiological reasons
7
When a person is dead?
Definitive, irreversible total damage of the brain
Cerebral functions are totally lost
Due to two different mechanisms:
1) Respiratory and circulatory arrest causing
secondary irreversible damage of brain
(non Heart Beating cadaver)
2) Devastating cerebral lesions
which cause total irreversible
damage of the brain
(Brain Death – Heart Beating cadaver)
8
Definition of death
(Universal death)
Simple uniform reliable
concepts & definitions
may increase public
confidence and trust
9
Capron , May 2012 Montreal Forum
Why
only Brain death is death ?
Heart, Lung, Liver, Kidneys etc.
are vital organs
but
can be supported by technology
or replaced by transplantation.
except
The Brain
10
Who may become
brain dead ?
Only patients with acute
cerebral lesion under
mechanical ventilation in ICU
Brain injury – Cerebral Hemorrhage
Ischemic Stroke – Brain Tumour
Anoxia – Cerebral Infection etc.
Determination of death
by neurological criteria
Determination of Death by Neurological criteria
EEG
CBF
Clinical
REFLEXES
“All the cerebral functions are
irreversibly lost”
14
Total Brain Infarct
Absence of cerebral blood flow
Death
15
Harvard Criteria - 1968
The Neurological Standard
16
Wijdicks E.
N Engl J Med 2001
17
Brain Death Diagnosis
Milestones
1. The etiology of the brain lesion is known
2. Exclude all potential confounding factors
3. The neurological examination is complete
and all clinical criteria are fulfilled
18
Etiology
19
NMR
20
Clinical examination
Prerequisites
•
•
•
•
•
•
Etiology must be known
Imaging of irreversible cerebral damage
Temp. >32 °C (“Normal” BP – SO2 – Na+)
Exclusion of medical confounding factors
Exclusion of drug effects on CNS
Exclusion of drug effects on clinical exam
(muscle relaxant agents, atropine etc.)
22
The Brainstem
23
Brainstem reflexes:
pathways
Oculocephalic
Painful stimuli
Oculovestibular
Corneal
Light response
Tracheal
VI
V
III
II
VII
VIII
X
XI
24
25
Pupillary response to light
Methodology & clinical experience
26
APNEA TEST
Absence of respiratory drive
130
78
23
130
98
PaCO2 > 60mmHg
100% Oxygen
27
Why brain dead patients
may move ?
Spinal reflexes in Brain Death
Brain infarct
Spine without
superior control
1
Spinal
Shock
2
Spinal function
recovery
3
Hyperexcitability
29
Are there factors that may
cause unreliable brain death
diagnosis?
CONFOUNDING FACTORS
Severe derangement in temperature,
blood pressure, oxygenation,
electrolytes, glusose, cortisol, T4)
Drugs (sedative/anesthetic - barbiturates !
– muscle relaxants )
Facial trauma – Cranial nerves lesions
31
Facial Trauma
32
If potentially
confounding factors
may be present
confirmatory tests
must be used
The absence of cerebral
perfusion is a simple,
clear, acceptable criteria,
easily to be understood
and demonstrated.
Cerebral angiogram.
Arch injection
Wijdicks, 2001
35
36
Trans Cranial Doppler
TCD
Brain Death
patterns
37
Angio-CT scan
Girlanda
R
BD standard – no confounding factors
F Procaccio 2012
Persistence of cerebral blood “flow”
after brain death
Flowers WM et al. Southern Medical Journal 93:364,2000
• Decompressing fractures
• Ventricular shunts
• Reperfusion (post-anoxic !)
• Decompressive Hemicraniectomy
39
Possible Pitfalls in BD diagnosis
1. the BD declared patient is not Dead
zero mistake must be ensured
2. the BD person is not BD declared
silent BD – Death is not equal - missing PODs
F Procaccio 2012
Mimicking Disorders
• Hypothermia
• Barbiturates
• Acute poisoning
• Endocrine crisis
(glucose – cortisol – T4)
• neurological diseases
41
“Neurological” conditions that may
be confused with Brain Death
•
•
•
•
•
•
Locked-in syndrome
Guillain-Barré syndrome
Demyelinating conditions
Post-anoxic coma
Brainstem encephalitis
“Medulla man”
42
The Medulla Man
43
Wijdicks E. J Neurol Neurosurg Psych 2001
F Procaccio 2012
Post-anoxic BD
swelling
6 hours
“flow”
Neuro ICU, Verona - 2005
45
46
Possible Pitfalls in BD diagnosis
1. the BD declared patient is not Dead
zero mistake must be ensured
2. the BD person is not BD declared
F Procaccio 2012
Brain Death Declaration
Certain diagnosis
plus
Legal procedures
49
Clinical Diagnosis
simple and reliable
Must be
complete
methodical
rigorous
50
Deceased Organ Donation
Dead Donor Rule
Dying process
• Threshold of irreversibility
• Clinical standard
• Confirmatory tests
Death determination (diagnosis)
(legal) Death declaration
• Adherence to guidelines
• Legal procedures
• The moment of Death
51
Death determination by neurological criteria
Brain death diagnosis (clinical criteria)
Coma
Brainstem
reflexes
+
apnea
etiology
x
Mandatory
EEG
Mandatory
CBF
x
no
x
CBF
In
Defined
Condition
s
children
x
x
All pts
or only
potential
donors?
all
other
>24hrs
anoxic
BD declaration (legal procedures)
Observation
period
N°
MD
Repeated
clincial tests
6 hrs
3
2
Country: Italy
Repeated
EEG
2
Repeated
CBF
Children
no
Law –Decree ?
National Guidelines ?
x
All pts
Or only
Potential
Donors?
all
!x!
!x!
Italy
52
Timing in Death declaration
ICU
Admission
1
Vegetative
Storm
(coning)
BD
criteria
2
Patient
treatment
Brain Death
Declaration
observation
3
4
Death
53
Common Principles for present/future ?
Citizens equal in death:
Death declaration independent from organ donation
Clear, simple and acceptable definitions, criteria and
procedures in death diagnosis
A «Universal death» independent
from clinical and (new) technical aspects
Clear legal procedures for death declaration
54
Suggestions
1. Treating physicians (Intensivists!) should be more
involved in BD diagnosis and potential donor
identification.
2. BD Pathophysiology based guidelines should
guide BD diagnosis and donor treatment.
3. Law and decrees should have (few) technical
details aimed to BD (legal) declaration
55
Key factors
1. Specific education and common language are
needed.
2. Quality of critical care may facilitate BD
diagnosis.
3. The probability of success in organ donation
reflects the capacity of declaring brain death
in all the patients fulfilling BD criteria.
56
Case study
Reversible Brain Death
57
A 55-yr-old man presented with cardiac arrest
preceded by respiratory arrest.
Cardiopulmonary resuscitation was performed,
spontaneous perfusion restored, and therapeutic
hypothermia was attempted for neural protection.
After rewarming to 36.5°C, neurologic examination
showed no eye opening or response to pain,
spontaneous myoclonic movements, sluggishly reactive
pupils, absent corneal reflexes, and intact gag and
spontaneous respirations.
Day 1
Facial Myoclonus
Over 24 hours, remaining cranial nerve function
was lost.
The neurologic examination was consistent
with brain death.
Apnea test and repeat clinical examination after a
duration of 6 hrs confirmed brain death.
Death was pronounced and
the family consented to organ donation.
Are there factors that may
cause unreliable brain death
diagnosis?
Twenty-four hrs after brain death pronouncement, on
arrival to the operating room for organ procurement,
the patient was found to have regained corneal
reflexes, cough reflex, and spontaneous respirations.
The care team faced the challenge of offering an
adequate explanation to the patient's family and
other healthcare professionals involved.
63
Would you consider propofol/fentanyl
a potential confounding factor
at hour 80 ?
1) Yes
2) No
3) maybe
66
The ideal practice is
to use confirmatory tests
only if necessary
to confirm the clinical examination.
Physicians should not go far
as to place blind faith in machinery and
the clinical diagnosis remains
a sacrosant principle.
EFM Wijdicks, 2001
67
Is an ancillary test
1) Useful
1) Mandatory
1) Unreliable
68
170
Hypothermia
Sedation
SEPs
F Procaccio 2012
195
NMR
200
CBF CCA
202
ventilation
withdrawal
Operating room
1°- 2° clinical exam + apnea test
Although the reversal was transient and did not impact the
patient's prognosis, it impacted his eligibility for organ
donation and cast doubt about the ability to determine
irreversibility of brain death findings in patients treated
with hypothermia after cardiac arrest.
CONCLUSIONS:
We strongly recommend caution in the determination of
brain death after cardiac arrest when induced hypothermia
is used. Confirmatory testing should be considered and a
minimum observation period after rewarming before brain
death testing ensues should be established.

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