Emergency lecture series Neurology Half academic Day BRAIN DEATH Mohammed Alshurem R2 Neurology resident 2013 July 24th
Content 1-Historical context 2-Definition 3-Diagnostic Criteria 4-Ancillary test 5-Organ donation
Historical context • before the 1800s: general medical opinion focused on the heart as the residence for a person’s central and controlling “life force.” • Late 1800s: Machado and his colleagues did number of experiments demonstrated situations in which patients with high intracranial pressure ceased to have respirations but continued to have beating hearts shortly thereafter • Horsley, Duckworth and Cushing noted that patients with disease states such as intracerebral hemorrhage and brain tumors that increase intracranial pressure tended to pass away first from respiratory failure rather than circulatory arrest.
mid-1970s: The advent of resuscitative measures such as electroshock and artificial ventilation, forced the medical community to reconsider the location of “vital principles” • after the first electroencephalogram was recorded by Bergerin 1929: Sugar and Gerard were able to show in cats that an occlusion of a carotid artery resulted in the complete abolition of electric potentials in the brain • Löfstedt and von Reisdescribed 6 patients with apnea and absent brainstem reflexes who showed no intracranial blood flow during cerebral angiography but who did not have subsequent cardiac arrest until 2 to 26 days afterward
1959: Mollaret and Goulon “coma dépassé,” meaning “a state beyond coma,” 23 ventilated patients in which loss of consciousness, brain stem reflexes, and spontaneous respirations were associated with absent encephalographic activity. • Wertheimer and Jouvet : description of ((death of the nervous system)), and criteria to stopping the ventilator in such cases.
Definition • Death is an irreversible, biological event that consists of permanent cessation of the critical functions of the organism as a whole. • Brain death implies the permanent absence of cerebral and brainstem functions.
Diagnostic Criteria • Guidelines Before American Academy of Neurology(1995-2010):
CMA- 1987 • The Clinical diagnosis Of brain death can be made when all the following criteria have been satisfied. 1.An Etiology has been established that is capable of causing brain death and potentially reversible conditions have been excluded 2.The Patient is in deep coma and shows no response within the cranial nerve distribution to stimulation of any part of the body. No Movements such as cerebral seizures, dyski-netic movements, "decorticate" Or decerebrate posturing arising from the brain are present 3.Brain-stem Reflexes are absent 4.The Patient is apneic when taken off the respirator for an appropriate time 5.The Conditions listed above persist when the patient is reassessed after a suitable interval
AAN Guidelines 2010 • 3 clinical finding to declare brain death • Come (with known irreversible cause) • Absence of brain stem reflex • Apnea
Prerequisites (all must be checked) •Coma, irreversible and cause known •Neuroimaging explains coma •Central nervous system (CNS) depressant drug effect absent (if indicated toxicology screen; if barbiturates given, serum level <10 g/mL) •No evidence of residual paralytics (electrical stimulation if paralytics used) •Absence of severe acid-base, electrolyte, endocrine abnormality •Normothermia or mild hypothermia (core temperature ≥36°C) •Systolic blood pressure ≥100 mm Hg •No spontaneous respirations
Examination (all must be checked) •Pupils nonreactive to bright light •Corneal reflex absent •Oculocephalic reflex absent (tested only if C-spine integrity ensured) •Oculovestibular reflex absent •No facial movement to noxious stimuli at supraorbital nerve, temporomandibular joint •Gag reflex absent •Cough reflex absent to tracheal suctioning •Absence of motor response to noxious stimuli in all 4 limbs (spinally mediated reflexes are permissible)
Apnea testing (all must be checked) •Patient is hemodynamically stable (even with the use of vasopressors) •Ventilator adjusted to provide normocarbia (Paco2 34–45 mm Hg) •Patient preoxygenated with 100% Fio2 for ≥10 minutes to Pao2 ≥200 mm Hg •Patient well-oxygenated with a positive end-expiratory pressure (PEEP) of 5 cm of water •Provide oxygen via a suction catheter to the level of the carina at 6 L/min or attach T-piece with continuous positive airway pressure (CPAP) at 10 cm H2O •Disconnect ventilator •Spontaneous respirations absent •Arterial blood gas drawn at 8–10 minutes, patient reconnected to ventilator •Pco2 ≥60 mm Hg, or 20 mm Hg rise from normal baseline value OR: •Apnea test aborted
Ancillary test • (only 1 needs to be performed; to be ordered only if clinical examination cannot be fully performed because of patient factors, or if apnea testing inconclusive or aborted) • Cerebral angiogram • TranscranialDoppler (TCD) • Electroencephalogram (EEG) • single-photon emission • computed tomography (SPECT)
When • severe facial trauma preventing complete brain stem reflex testing, • preexisting pupillary abnormalities, and • sleep apnea or severe pulmonary disease resulting in chronic retention of carbon dioxide Not confirmatory or supplemental
cerebral angiography • Invasive • Cerebral circulatory arrest is defined by a lack of opacification of the internal carotid arteries above the level of the petrous portion or of the vertebral arteries above the level of the atlanto-occipital junction
Transcranial Doppler • Operator and patient dependent • Depend on ability to obtain reliable signal • 10% to 20% of patients will not have an adequate bone window for ultrasound transmission. • when obtained, TCDs have a specificity of 98% to 100% and a sensitivity ranging from 88% to 99%.
EEG • simple to perform and provides insight into the cortical activity of the brain • difficult to interpret secondary to artifact in either a positive or negative direction. • sedation and hypothermia may produce a false-positive result
(SPECT) ‘‘hollow skull’’ or ‘‘empty light bulb’’ sign
Mimics need to R/O • fulminant Guillain-Barre syndrome • baclofen overdose • barbiturate overdose • delayed vecoroniumclearance • hypothermia
Red Flag • normal computed tomography (CT) scan • unsupported blood pressure • absence of diabetes insipidus • marked heart rate variations • fever or shock • marked metabolic acidosis • hypothermia lower than 32°C as this is often accidental and reversible • marked miosis (opiate or organophosphate toxicity) • myoclonus (lithium or selective serotonin reuptake inhibitor [SSRI] toxicity) • rigidity (SSRI or haloperidol toxicity) • positive urine or serum toxicology
Organ donation • organs that can be transplanted are the kidneys, heart, lungs, liver, pancreas, and intestines • A single donorcanprovideorgans for 8 people • Organ donation in numbers (As of 31 December 2012) • DONORS 120 • Recipients 346 • Patients on the Waiting List 1250
Who is a potential organ donor? • A potential organ donor is a mechanically ventilated patient of any age with severe primary neurological damage. , some patients may present with severe neurological damage that is secondary to an end-stage organ failure such as pulmonary or cardiac failure. In most cases, these people are diagnosed with: • stroke • cerebral anoxia (following cardiopulmonary arrest, hanging, drowning, poisoning, etc.) • encephalopathy • major, severe head trauma
Tissue donation • Bone, skin, heart valves, tendons, and corneas are the main types of tissues used for grafts • A single donorcanprovide tissues to 15 other people. • Héma-Québec
References • Diagnosis of brain death, G Bryan Young. Uptodate. • Assessment of Brain Death in the Neurocritical Care Unit, David Y. Hwang, Neurosurgery Clinics of North AmericaVolume24, Issue 3, July 2013, Pages 469–482 • Evidence-based guideline update:Determining brain death in adults:Report of the Quality Standards Subcommittee of the American Academy of Neurology. Eelco F.M. Wijdicks, Panayiotis N. Varelas, Gary S. Gronseth, et al Neurology 2010;74;1911-1918 • http://www.transplantquebec.ca • http://www.hema-quebec.qc.ca
THANK YOU • ANY QUESTION What is the treatment of brain death ?