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Anoxic Auguring: Neurological Prognostication After Cardiopulmonary Resuscitation. Robert Altman PGY 4, Neurology Resident McGill University. Where do we stand in 2011?. Division of Neurology, McGill University Health Center. May 18 th 2011. π ρόγνωση Prognosis “Fore-knowing” Φρόνησις

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anoxic auguring neurological prognostication after cardiopulmonary resuscitation

Anoxic Auguring:Neurological Prognostication After Cardiopulmonary Resuscitation

Robert Altman

PGY 4, Neurology Resident

McGill University

Where do we stand in 2011?

Division of Neurology, McGill University Health Center

May 18th 2011

slide2
πρόγνωση
  • Prognosis
  • “Fore-knowing”

Φρόνησις

  • Phronesis
  • “Practical wisdom”
case 1
Case 1
  • 55 M collapses while jogging
  • CPR immediately initiated by bystander
  • V-fib arrest; circulation restored after 6 minutes
  • Exam (day 1): comatose, absent pupillary and corneal reflexes, extensor posturing to pain, myoclonic status epilepticus
  • CT head (day 2): Normal study
  • SSEP (day 3): Absent N20 responses
  • Exam (day 3): Unchanged
case 2
Case 2
  • 35 M collapses while playing basketball
  • CPR immediately initiated by bystander
  • PEA arrest; circulation restored after 20 minutes
  • Induced hypothermia x 24 hours (32 degrees C)
  • Exam (day 1):Comatose, pupils fixed, triggers ventilator but otherwise no evidence of intact brainstem function, no spontaneous movements or motor response to noxious stimuli
  • EEG (day 2): Severe diffuse slowing of cerebral activity
  • Exam (day 3): Comatose, pupils reactive, oculocephalic, corneal, and gag reflexes intact, triggers ventilator, flexor posturing of upper limbs to pain, no spontaneous movements
case 3
Case 3
  • 71M with HTN, CAD (previous CABG), collapsed at home
  • No CPR administered
  • PEA arrest; circulation restored after 20 minutes
  • Exam (day 1): Comatose, R pupil reactive/L pupil fixed, corneal reflex present but sluggish, no ocular response to cold calorics, no spontaneous movements, left arm and leg withdraw to painful stimuli, bilateral Babinski signs
  • MRI brain (day 2): Cerebral infarctions in superficial and deep watershed territories bilaterally (L > R)
  • SSEP (day 3): N20 response present on right, absent on left
  • Exam (day 3): Unchanged
outcome
Why does neurology get called to evaluate these cases?

Outcome?

Poor or favourable?

Why? What do you base your judgement on?

outline
Outline
  • Cases
  • Historical Perspective
  • Prognostication Guidelines
  • The Era of Hypothermia
  • Approaching the Family
  • Return to Cases
  • Take Home Points
mission im possible
Mission (im)possible?

The neurologists role: To predict with perfect accuracy the likelihood of awakening and (if the patient survives) future morbidity.

self fulfilling prophecy
Self-fulfilling prophecy?
  • A physician’s negative expectation or overreliance on laboratory tests affects management decisions and thus outcome.
  • Therefore paramount that studies adhere strictly to independent assessment of prognostic indicators and outcomes
poor prognosis
‘Poor’ Prognosis
  • Glasgow Outcome Scale (GOS) ≤ 3
    • Cerebral Performance Scale (CPC) ≥ 3
  • Emphasis on the ‘poor’ because may facilitate decision for withdrawal of life-sustaining therapies
  • Tests ideally have a 0% FPR for determining poor prognosis, narrow CI’s

N.B. No postarrest physical examination finding or diagnostic study has as yet predicted poor outcome of comatose cardiac arrest survivors during the first 24 hours after ROSC

outcomes
Outcomes

Bernat. Neurology® Clinical Practice 2010;75(Suppl 1):S33–S38

history of prognostication
History of Prognostication
  • Levy et al (1985) establishes algorithms for neurological prognosis
    • Determinations derived from a single cohort study, 211 patients
    • Not without limitations
      • Statistical uncertainty
      • Since (late 70’s); revolution in critical care since this era
      • How many patients suffered from a cardiac arrest in the Levy cohort? How many were cooled?
        • Only 71% suffered cardiac arrest
        • TH only introduced in 2002

Levy DE, et al. JAMA 1985;253:1420-1426

slide15
Meta-analysis of relevant literature from 1966-2006;

391 papers reviewed and rated.

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

aan recommendations
AAN Recommendations

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

the tools
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)
the tools1
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)

Clinical Exam

Direct assessment

Brainstem

physical exam clinical findings
Physical exam, clinical findings
    • Present vs. Absent (day 1 to 3)
    • Pupils (CN II,III)
    • Corneal reflex (CN V, VII)
    • Cold calorics(CN VIII, VI, III, MLF)
  • Motor responses (day 1 to 3)
    • Flexion vs. extension / none

0 % FPR for poor outcome, narrow CI’s, 10 studies.

clinical exam
Clinical Exam
  • Since Levy et al.
    • Prospective, class I studies.

Zandbergen, et al. Neurology 2006;66:62–68.

point in fact clinical exam
Point in fact – Clinical Exam
  • The brainstem is more resistant to anoxia than the cortex, thus if abolished BS reflex, this generally implies a severely damage cortex
  • Preserved BS reflexes by no means imply intact cortical function
  • No direct way of evaluating cortical activity in an unconscious patients
related to poor outcome but insufficient predictive value
Related to Poor Outcome but Insufficient Predictive Value
  • Age
  • Sex
  • Cause of arrest
  • Type of arrhythmia (vfib or asystole)
  • Total time of arrest
  • Duration of CPR

Based in 2 large prospective studies involving 774 patients

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

the tools2
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)
blood work biochemical signs
Blood work – Biochemical Signs
  • NSE (neuron-specific enolase)
  • S100 (glial protein)
  • BB fraction of creatine kinase (serum or csf)
  • Neurofilament protein
  • Combination panels
blood work biochemical signs1
Blood work – Biochemical Signs
  • NSE (neuron-specific enolase)
  • S100 (glial protein)
  • BB fraction of creatinekinase (serum or csf)
  • Neurofilament protein
  • Combination panels
blood work biochemical signs2
Blood work – Biochemical Signs
  • NSE (neuron-specific enolase)
    • ≥33µg/L, b/w 1-3d post arrest
    • Reflects diffuse CNS injury
      • Only validated use in carcinoid & other tumors
    • Not commonly available in N. America
      • Not at MUHC, CHUM, Ontario
    • Variability in assays and cut-off values
    • Class B
  • 0 % FPR for poor outcome, CI 0-3;
  • One class I study
the tools3
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)
the tools4
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)
neuroimaging
Neuroimaging
  • Findings correlate poorly with functional prognosis
  • Performed to rule out primary neurological catastrophe, as aetiology of cardiovascular event
  • However,
    • CT often normal on day 1
  • Technical barriers may preclude neuroimaging
    • i.e. Hemodynamic instability, inability to transfer
  • Class U

Diagnostic value not prognostic

the tools5
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)
the tools6
The Tools
  • Physical exam, clinical findings
  • Blood work – Biochemical Signs
  • Neuroimaging (CT, MRI)
  • Electrophysiology (EEG, SSEP)

Cortical and subcortical GM

indirectly

EEG , SSEP

slide33
EEG
  • Early myoclonic status correlates with poor outcome
    • At 24hrs, 0% FP
    • Bilaterally synchronous twitches of limb, trunk or facial muscles
    • Supported by autopsy and multiple trials
  • Status epilepticus, GTC seizures, multifocal asynchronous myoclonus
    • Represent nonspecific indicator of metabolic encephalopathy without real prognostic value

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

slide34
EEG
  • FPR for poor outcome 3%(95% CI: 0.9% to 11%) with malignant EEG patterns
    • Malignant categories include suppression, burst-suppression, alpha and theta pattern coma, and generalized periodic complexes combined;

“(malignant EEG group)...therefore strongly but not invariably associated with poor outcome”

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

myoclonic status
Myoclonic Status

18 hours after resuscitation, patient was in coma with intact brainstem reflexes

86 F, post cardiac rest

Etiology unclear

Duration of downtime unknown

Clinical movements q3-5

what is ssep
What is SSEP?
  • SSEP = Somatosensory Evoked Potential
  • N20 response primary somatosensory cortex
    • 200 consecutive rapid stimulations are given to the median nerve
    • Recorded at
      • brachial plexus
      • cervical spinal cord
      • At 20 msec, contralateralsomatosensory cortex
ssep and prognosis
SSEP and Prognosis
  • Bilateral absence of the N20 component of the SSEP with median nerve stimulation recorded on days 1 to 3 after CPR accurately predicts a poor outcome

Zandbergen, et al. Neurology 2006;66:62–68.

pros cons of ssep
Pros/Cons of SSEP

+: not influenced by medications, able to be performed when brainstem testing limited

  • mechanical or metabolic reasons; including hypothermia

- : confounded in many ways

  • any interruption in somatosensory pathways invalidates test

Tiainen M, et al. Crit Care Med 2005; 33: 1736–1740

ssep s clinical practice
SSEP’s: Clinical Practice
  • Physicians’ use of SSEP fuel decisions about withdrawal of life support.
  • 58 comatose CPR survivors referred for neurologic consultation
  • SSEP testing correlated best with waiting time to withdrawal of life-sustaining therapies.
    • 40 patients whose life support was eventually withdrawn, the median waiting time was 7 days for patients with preserved SSEPs and only 1 day in patients with bilaterally absent N20 SSEP components.

Geocadin RG et al. Neurologic prognosis and withdrawal of life support after resuscitation from cardiac arrest. Neurology 2006 Jul 11; 67:105-8.

slide44
AAN 2006 Practice Parameter

Confounders

  • Hypothermia
  • NM blocking agents
  • Large dose sedatives
  • Organ failure
  • Shock

Absent pupils/corneal and extensor/no motor response.

outline1
Outline
  • Cases
  • Historical Perspective
  • Prognostication Guidelines
  • The Era of Hypothermia
  • Approaching the Family
  • Return to Cases
  • Take Home Points
history of prognostication1
History of Prognostication
  • Levy et al (1985) establishes algorithms for neurological prognosis
    • determinations derived from a single cohort study
    • Not without limitations
  • Therapeutic hypothermia early 2000’s, 2 major publications in the NEJM 2002
    • TH Increased the rate of a favourable neurologic outcome and reduced mortality.

Levy DE, et al. JAMA 1985;253:1420-1426

N Engl J Med 2002;346:549-56

N Engl J Med 2002;346:557-63

the conundrum
The Conundrum
  • TH now used for neurological protection for a multitude of other life-threatening catastrophes
    • Worldwide 25% - 75% of all admitted resuscitated patients
  • Prognostication tools thus need revalidation
  • Life-sustaining therapies outpacing our capacity for accurately predicting outcomes
era of therapeutic hypothermia th
Era of Therapeutic Hypothermia (TH)
  • Studies ongoing and constantly emerging
  • Single studies show cooling:
    • Delayed motor response up to 6 days; 3 of 37 regained awareness
        • E. Thenayan, M. Savard et al. Neurology 2008;71:1535–1537
    • Hypothermia to 32°C or above increases latency of SSEP’s by approximately 15%, reductions of temperature below 30°C can decrease the N20 amplitude by up to 20%
    • Decreases NSE levels
      • May reflect neuroprotection?
        • M.Tiainen, Risto O. Roine. et al. Stroke 2003;34;2881-2886
dr bryan young
Dr. Bryan Young

“It is highly likely that the factors that have been shown to be reliable predictors in the past — such as loss of pupillary and corneal reflexes and of somatosensory-evoked responses — will be validated.”

“However, the timing of the testing of some variables may require adjustment”

slide52
192 patients (103 TH vs 89 NT)
  • Primary outcome = in hospital death (GOS 1)
  • The absence of pupillary light responses, corneal reflexes, and extensor or absent motor response at 72h remained accurate predictors (p < 0.0001 for all)
  • Myoclonic status epilepticus (p < 0.0002)
  • NSE > 33 ng/ml has a high false-positive rate in patients treated with hypothermia and should be interpreted with caution

J Fugate, E F.M. Wijdicks et al ANN NEUROL 2010;68:907–914

outline2
Outline
  • Cases
  • Historical Perspective
  • Prognostication Guidelines
  • The Era of Hypothermia
  • Approaching the Family
  • Return to Cases
  • Take Home Points
discussion with family
Discussion with family
  • Uncertainty furthers emotional distress of a grieving and anxious family
  • Respect decision made by the patient’s lawful surrogate decision-maker who attempts to faithfully represent the treatment preferences of the patient
  • Compassionate communication
  • Encouragement of emotions
  • Appreciation of personal values and religious preferences
  • Define “poor outcome”
    • PVS

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

poor outcome
“Poor outcome”
  • Terms
    • “Severely disabled state, requiring long-lasting or indefinite comprehensive nursing care”
    • “Hope for significant recovery is unrealistic”
    • “Chances of meaningful recovery extremely negligible”
    • “Fully dependent state of living”
  • Some possible reasonable options
    • Extubation
    • Discontinuation of ionotropes, vasopressors
    • Discontinuation of ivf, nutrition
    • Turn off monitor

E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203

persistent vegetative state pvs
Persistent Vegetative State (PVS)

Wakefulness without awareness

Bernat JLAnnu Rev Med 2009;60:381–392.

pvs pathophysiology
PVS Pathophysiology
  • Extreme reductions in cerebral blood flow and metabolism, measured with positron emission tomography (PET)
  • CT and MRI scans show progressive and profound cerebral atrophy in cases of vegetative state
    • Terry Schiavo
      • Brain at autopsy weighed 615g
      • Normal adult brain 1300-1500g
food for thought
Food for Thought
  • Recent fMRI has thrown into question our understanding of disordered consciousness
  • Case reports
  • 2006, Owen and colleagues; Science
    • 23 yo TBI victim in PVS for 5 months able to “wilfully modulate” brain regions required for volleying a tennis ball and looking at objects in her home while navigating room to room
  • 2010, Monti and colleagues; NEJM
    • 4/23 subjects in PVS able to activate appropriate brain regions
slide61
Owen AM, Coleman MR, Boly M, Davis MH, Laureys S, Pickard JD. Detecting awareness in the vegetative state. Science 2006;313:1402
prognosis in pvs
“Prognosis” in PVS
  • Major grey area
    • depends mostly on the cause and extent of the brain damage producing the syndrome
  • Certain patients that modulate brain activity (fMRI; Owen, Monti et al.) may have better prognoses / predictors of recovery.
    • Need validation studies, larger cohorts
    • Not available outside select centers
    • Still very far from clinical practice guidelines

Bernat JL. Chronic consciousness disorders. Annu Rev

Med 2009;60:381–392.

costs of maintaining pvs
Costs of maintaining PVS
  • Psychological
    • Was the test a false positive?
    • Will recovery occur?
  • Emotional
    • Family / loved-ones
  • Financial
    • Hospital
    • Caregiver
outline3
Outline
  • Cases
  • Historical Perspective
  • Prognostication Guidelines
  • The Era of Hypothermia
  • Approaching the Family
  • Return to Cases
  • Take Home Points
case 11
Case 1
  • 55 M collapsed while jogging
  • CPR immediately initiated by bystander
  • V-fib arrest; circulation restored after 6 minutes
  • Exam (day 1): comatose, absent pupillary and corneal reflexes, extensor posturing to pain, myoclonic status epilepticus
  • CT head (day 2): Normal study
  • SSEP (day 3): Absent N20 responses
  • Exam (day 3): Unchanged
  • *Final outcome:

1) Death secondary to sepsis from pneumonia <30d.

2) Glasgow Outcome Scale 1.

case 21
Case 2
  • 35 M collapses while playing basketball
  • CPR immediately initiated by bystander
  • PEA arrest; circulation restored after 20 minutes
  • Induced hypothermia x 24 hours (32 degrees C)
  • Exam (day 1):Comatose, pupils fixed, triggers ventilator but otherwise no evidence of intact brainstem function, no spontaneous movements or motor response to noxious stimuli EEG (day 2): Severediffuse slowing of cerebral activity
  • Exam (day 3): Comatose, pupils reactive, oculocephalic, corneal, and gag reflexes intact, triggers ventilator, flexor posturing of upper limbs to pain, no spontaneous movements
  • *Final outcome:
  • 1) Probable HOCM.
  • 2) Post anoxic encephalopathy. Persistent Vegetative State.
  • 3) Glasgow Outcome Scale 2 at 6 months.
case 31
Case 3
  • 71M with HTN, CAD (previous CABG), collapsed at home
  • No CPR administered
  • PEA arrest; circulation restored after 20 minutes
  • Exam (day 1): Comatose, R pupil reactive/L pupil fixed, corneal reflex present but sluggish, no ocular response to cold calorics, no spontaneous movements, left arm and leg withdraw to painful stimuli, bilateral Babinski signs
  • MRI brain (day 2): Cerebral infarction in superficial and deep watershed territories bilaterally (L > R)
  • SSEP (day 3): N20 response present on right, absent on left
  • Exam (day 3): Unchanged
  • *Final outcome:

1) Mild ischemic cortical & subcortical damage.

2) Residual R hemiparesis.

3) Post-anoxic myoclonus (Lance-Adams).

4) Glasgow Outcome Scale 4at 6 months.

take home points neurologic prognostication
Take-Home PointsNeurologic Prognostication
  • Our tools allow for an accurate prediction of poor neurologic outcome
    • “Indeterminate” largely equals =
  • Timing of exam
  • Clinical exam remains the most reliable method for determining poor outcomes
  • Current prognostication evidence predates TH era; and thus need to interpret with caution
  • Structured, compassionate approach to family; define what ‘poor’ outcome means in appropriate terms
3 key references
3 Key References
  • N Engl J Med 2009;361:605-11

Neurology 2006;67;203

JAMA. 2004;291:870-879

references cited
References Cited
  • Young B. N Engl J Med 2009;361:605-11
  • E.F.M. Wijdicks, A. Hijdra, G. B. Young, et al. Neurology 2006;67;203
  • Mayo Clin Proc. 2005;80(8):1037-1046
  • Bernat. Neurology® Clinical Practice 2010;75(Suppl 1):S33–S38
  • Bernard SA, Gray TW, Buist MD, et al: Treatment of comatose survivors of out-ofhospital cardiac arrest with induced hypothermia. N Engl J Med 2002; 346:557–563
  • Circulation 2010;122;S768-S786
  • Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med 2002; 346:549–556
  • Owen AM, Coleman MR, Boly M, Davis MH, Laureys S, Pickard JD. Detecting awareness in the vegetative state. Science 2006;313:1402
  • Thenayan EA, et al. Electroencephalogram for prognosis after cardiac arrest. J Crit Care. 2010 Jun;25(2):300-4.
  • Monti et al. Willful Modulation of Brain Activity in Disorders of Consciousness. N Engl J Med 2010;362:579-89
  • Neuroopthalmology review manual: Kline
  • MedLink: myoclonic status epilepticus
ndd n eurological d etermination of d eath
NDD (neurological determination of death)
  • Aetiology established that can cause irreversible death
  • Deep coma
    • Absence of motor responses to stimuli, no spontaneous or abnormal mvmts (dyskinesia, posturing) or seizures
  • Absence of BS reflexes
  • No spontaneous breathing during apnea test
  • No confounders
  • 2 exams, 2 independent MD’s
  • Infants (≥30d and <1yr); rpt exam recommended
  • In case of cardiac arrest, clinical evaluation of NDD delayed 24hrs subsequent to CPR
    • N.b. spinal reflexes may exist
  • Date and time of death = first NDD
brain death exam
Brain Death Exam
  • Brainstem
    • Pupils
      • ≥4mm, unresponsive to light
    • Corneals
      • Movement of jaw or lids excludes NDD
    • OCR
      • Ignore if trauma
    • Calorics
      • 30 degrees
      • ≥50cc ICE water quickly. If no eye movement, wait 5 min and try contralateral side
    • Pharyngeal
      • Stimulate posterior pharynx
      • Suction the ETT
      • Depress larynx, swallow reflex
    • Apneatest
cold caloric testing vestibulo ocular reflex vor
Cold Caloric TestingVestibulo-Ocular Reflex (VOR)

Slow phase

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 vestibulo ocular reflex vor
Warm Caloric TestingVestibulo-Ocular Reflex (VOR)

Increases resting state vestibular tone

Rarely done in neurology

apnea test
Apnea Test
  • Pre-oxygenate with 100% FiO2 for 10-15 min
  • 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 resp. effort x 10 min
  • Repeat ABG and reconnect ventilator
    • Test + if
      • PaCO2 >60mmHg and rise in 2mmHg/min
      • PH <7.28
      • No respiratory efforts demonstrated
      • Stop if HD instability or desaturation occurs
ancillary test
Ancillary test
  • Cerebral angiography or radio-isotope scan
    • Absence of intracranial blood
slide78
+ LR (CI)

- LR (CI)

Pooled Clinical Signs in the Prognosis of Post–Cardiac Arrest Coma

LR for poor neurological outcome demonstrated.

JAMA. 2004;291:870-879

rational clinical exam jama 2004
Rational Clinical Exam – JAMA 2004

Pooled Clinical Signs in the Prognosis of Post–Cardiac Arrest Coma

+ LR (CI)

- LR (CI)

JAMA. 2004;291:870-879

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