Brain Death Anatomy and Physiology Joel S. Cohen, M.D. Joel S. Cohen, M.D. Associate Professor of...
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Transcript of Brain Death Anatomy and Physiology Joel S. Cohen, M.D. Joel S. Cohen, M.D. Associate Professor of...
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
Brain StemBrain Stem
Midbrain
Cranial Nerve III
pupillary function
eye movement
Brain StemBrain Stem
Pons
Cranial Nerves IV, V, VI
conjugate eye movement
corneal reflex
Brain StemBrain Stem
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
Causes of Brain DeathCauses of Brain Death
Normal Cerebral Hemorrhage
Causes of Brain DeathCauses of Brain Death
Normal Subarachnoid Hemorrhage
Causes of Brain DeathCauses of Brain Death
Normal Trauma
Causes of Brain DeathCauses of Brain Death
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
Confirmatory TestingConfirmatory Testing
EEG
Normal Electrocerebral Silence
Confirmatory TestingConfirmatory Testing
Cerebral Cerebral AngiographyAngiography
Normal No Intracranial Flow
Confirmatory TestingConfirmatory Testing
Technetium-99 Isotope Brain ScanTechnetium-99 Isotope Brain Scan
Confirmatory TestingConfirmatory Testing
MR- Angiography MR- Angiography
Confirmatory TestingConfirmatory Testing
Transcranial Ultrasonography
Confirmatory TestingConfirmatory Testing
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