dr. cohen

Brain DeathBrain DeathAnatomy and Anatomy and PhysiologyPhysiology

Joel S. Cohen, M.D.Joel S. Cohen, M.D. Associate Professor of Clinical NeurologyAssociate Professor of Clinical Neurology

Albert Einstein College of MedicineAlbert Einstein College of Medicine

Historical PerspectiveHistorical Perspective

Prior to the advent of mechanical Prior to the advent of mechanical respiration, death was defined as respiration, death was defined as the cessation of circulation and the cessation of circulation and

breathing breathing

Historical PerspectiveHistorical Perspective

1959 1959 Coma de’passe’Coma de’passe’ Mollaret and Goulon Mollaret and Goulon

1968 1968 Irreversible Coma/Brain DeathIrreversible Coma/Brain Death Harvard Harvard Medical School Ad Hoc CommitteeMedical School Ad Hoc Committee

1981 Uniform Determination of Death Act - 1981 Uniform Determination of Death Act -

President’s Commission for the Study of Ethical President’s Commission for the Study of Ethical Problems in MedicineProblems in Medicine

1994 American Academy of Neurology Guidelines 1994 American Academy of Neurology Guidelines for the determination of Brain Death for the determination of Brain Death

2005 NYS Guidelines for Determining Brain Death2005 NYS Guidelines for Determining Brain Death

Brain Death Current Brain Death Current ConsensusConsensus

Absent Cerebral Function Absent Cerebral Function

Absent Brainstem Function Absent Brainstem Function

Apnea Apnea

Normal Brain AnatomyNormal Brain Anatomy

Normal Brain AnatomyNormal Brain Anatomy

Cerebral Cortex

Brain Stem

Reticular Activating

System

Cerebral CortexCerebral Cortex

CognitionCognition Voluntary Voluntary

MovementMovement SensationSensation

Brain StemBrain Stem


Midbrain

Cranial Nerve III

pupillary function

eye movement


Pons

Cranial Nerves IV, V, VI

conjugate eye movement

corneal reflex


Medulla

Cranial Nerves IX, X

Pharyngeal (Gag) Reflex

Tracheal (Cough) Reflex

Respiration

Reticular Activating Reticular Activating System System

Receives multiple Receives multiple sensory inputssensory inputs

Mediates Mediates wakefulnesswakefulness

Causes of Brain DeathCauses of Brain Death

Normal Cerebral Anoxia


Normal Cerebral Hemorrhage


Normal Subarachnoid Hemorrhage


Normal Trauma


Normal Meningitis

Mechanism of Cerebral Mechanism of Cerebral DeathDeath

Neuronal Injury

Decreased Intracranial Blood Flow

Neuronal Swelling

Increased Intracranial Pressure

ICP>MAP is incompatible

with life

Conditions Distinct Conditions Distinct From Brain DeathFrom Brain Death

Persistent Vegetative StatePersistent Vegetative State

Locked-in SyndromeLocked-in Syndrome

Minimally Responsive StateMinimally Responsive State

Persistent Vegetative Persistent Vegetative StateState

Normal Sleep-Wake Cycles Normal Sleep-Wake Cycles

No Response to Environmental No Response to Environmental StimuliStimuli

Diffuse Brain Injury with Diffuse Brain Injury with Preservation of Brain Stem Preservation of Brain Stem FunctionFunction

Locked-in SyndromeLocked-in Syndrome

Ventral Pontine Infarct

Complete Paralysis

Preserved Consciousness

Preserved Eye Movement

Minimally Responsive Minimally Responsive StateState

Diffuse or Multi-Focal Brain InjuryDiffuse or Multi-Focal Brain Injury

Preserved Brain Stem FunctionPreserved Brain Stem Function

Variable Interaction with Variable Interaction with Environmental StimuliEnvironmental Stimuli

Static Encephalopathy

Brain Death Brain Death Neurological Neurological ExaminationExamination

Clinical Prerequisites:Clinical Prerequisites:

Known Irreversible CauseKnown Irreversible Cause

Exclusion of Potentially Reversible Exclusion of Potentially Reversible ConditionsConditions

Drug Intoxication or PoisoningDrug Intoxication or Poisoning Electrolyte or Acid-Base ImbalanceElectrolyte or Acid-Base Imbalance Endocrine DisturbancesEndocrine Disturbances

Core Body temperature > 32° CCore Body temperature > 32° C

Brain Death Brain Death Neurological Neurological ExaminationExamination

ComaComa

Absent Brain Stem ReflexesAbsent Brain Stem Reflexes

ApneaApnea

ComaComa

No Response to Noxious StimuliNo Response to Noxious Stimuli

Nail Bed PressureNail Bed Pressure

Sternal RubSternal Rub

Supra-Orbital Ridge PressureSupra-Orbital Ridge Pressure

Absence of Brain Stem Absence of Brain Stem ReflexesReflexes

Pupillary ReflexPupillary Reflex

Eye MovementsEye Movements

Facial Sensation and Motor Facial Sensation and Motor ResponseResponse

Pharyngeal (Gag) ReflexPharyngeal (Gag) Reflex

Tracheal (Cough) ReflexTracheal (Cough) Reflex

Pupillary ReflexPupillary Reflex

Pupils dilated with no constriction to bright light

Eye Movements Eye Movements

Occulo-Cephalic Response

“Doll’s Eyes Maneuver”

Eye MovementsEye Movements

Oculo-Vestibular Response

“Cold Caloric Testing”

Facial Sensation and Facial Sensation and Motor ResponseMotor Response

Corneal ReflexCorneal Reflex

Jaw ReflexJaw Reflex Grimace to Supraorbital orGrimace to Supraorbital or

Temporo-Mandibular PressureTemporo-Mandibular Pressure

Apnea TestingApnea Testing

PrerequisitesPrerequisites

Core Body Temperature > 32° CCore Body Temperature > 32° C

Systolic Blood Pressure ≥ 90 mm Systolic Blood Pressure ≥ 90 mm HgHg

Normal ElectrolytesNormal Electrolytes

Normal PCO2Normal PCO2

Apnea TestingApnea Testing

1. Pre-Oxygenation1. Pre-Oxygenation 100% Oxygen via Tracheal Cannula 100% Oxygen via Tracheal Cannula PO2 = 200 mm HgPO2 = 200 mm Hg

2. Monitor PCO2 and PO2 with pulse oximetry2. Monitor PCO2 and PO2 with pulse oximetry

3. Disconnect Ventilator3. Disconnect Ventilator

4. Observe for Respiratory Movement until 4. Observe for Respiratory Movement until PCO2 = 60 mm HgPCO2 = 60 mm Hg

5. Discontinue Testing if BP < 90, PO2 5. Discontinue Testing if BP < 90, PO2 saturation decreases, or cardiac dysrhythmia saturation decreases, or cardiac dysrhythmia observed observed

Confounding Clinical Confounding Clinical ConditionsConditions

Facial TraumaFacial Trauma

Pupillary AbnormalitiesPupillary Abnormalities

CNS Sedatives or Neuromuscular CNS Sedatives or Neuromuscular BlockersBlockers

Hepatic FailureHepatic Failure

Pulmonary DiseasePulmonary Disease

Observations Observations Compatible with Brain Compatible with Brain

DeathDeath Sweating, BlushingSweating, Blushing

Deep Tendon ReflexesDeep Tendon Reflexes

Spontaneous Spinal Reflexes- Triple Spontaneous Spinal Reflexes- Triple FlexionFlexion

Babinski Sign Babinski Sign

Confirmatory TestingConfirmatory Testing

Recommended when the proximate Recommended when the proximate cause of coma is not known or when cause of coma is not known or when confounding clinical conditions limit confounding clinical conditions limit the clinical examinationthe clinical examination


EEG

Normal Electrocerebral Silence


Cerebral Cerebral AngiographyAngiography

Normal No Intracranial Flow


Technetium-99 Isotope Brain ScanTechnetium-99 Isotope Brain Scan


MR- Angiography MR- Angiography


Transcranial Ultrasonography


Somatosensory Evoked Potentials Somatosensory Evoked Potentials

Concern for man and his fate must Concern for man and his fate must always form the chief interest of always form the chief interest of all technical endeavors. Never all technical endeavors. Never forget this in the midst of your forget this in the midst of your

diagrams and equations. diagrams and equations.

Albert Einstein Albert Einstein

dr. cohen

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