Brain Stem Death

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New Guidelines In Diagnosis Of Brain Stem Death In ICU Mohamed Elsharkasy, M.D. Prof. of anaesthesia and intensive care FOM-SCU 2014

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Objectives: 1. Biological and brain stem death (BSD) 2. Types of coma 3. Clinical diagnosis of BSD 4. Regional rules and laws This is a summary of the American Academy of Neurology (AAN) guideline update (Neurology® 2010;74:1911–1918) on determining brain death in adults.

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Biological death ( traditional concept of death ) : It is cessation of respiration and circulation of an organism. Brain stem death (= determination of death by neurologic criteria ): It is a cessation of CNS functions, i.e. represent cessation of the harmony of life. This means simply that the brain is no longer alive and cannot be brought back to life .

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Coma: It is absence of arousal and awareness Recovery persistent coma ( with some degree of disability ) Vegetative state Brain stem death (With loss of cortical activity but have (with no brain stem reflexes spontaneous respiration and some or respiration ) never regains brain stem reflexes ) any brain functions

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History of BSD 1950's: ACLS and ventilators saved lives But there were also unanticipated outcomes as the physicians saw things they never saw before: Clinicians saw patients in a state "beyond coma" EEGers saw electrocerebral silence Pathologists saw the "respirator brain" 1960's: term "brain death" comes into use 1968: Harvard Criteria for brain death: Loss of animation, brainstem reflexes, and respiration Electrocerebral silence Persistence of the condition for 24 hours (1995, 2010): American Academy of Neurology This presentation is based on the AAN 2010 guideline which are 100% specific

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Systematic approach for the clinical diagnosis of brain stem death: A) Necessary preconditions: . Irreversible structural brain damage (e.g. SAH, head trauma ,meningitis, prolonged CA, massive stroke). Sufficient time has elapsed to insure irreversibility . Absence of primary hypothermia. . Absence of complicating medical conditions (e.g. metabolic, endocrine, electrolyte or acid –base disturbance) . Absence of drug intoxication(after 3 days or toxicology screen ) or NMB

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B) The three cardinal findings in brain stem death are: 1.Coma or unresponsiveness , 2.Absence of brain stem reflexes , 3.Apnea 1. Coma or unresponsiveness : GCS: 3 No eye movement or motor response to verbal or noxious stimuli Exclude any movements of spinal cord origin (may be preserved in some patient) “spinal withdrawal

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2. Absence of brain stem reflexes: a. Pupils: i . No response to direct bright light i i . Mid-position(4 mm to 6 mm) b. Ocular movement: i . No oculocephalic reflex (doll’s eyes response) Precautions : cervical vertebrae & ETT i i . No oculovestibular reflex (iced water calorics reflex ). Precautions : position, time allowed, ear, (eye observed for 30 seconds after irrigation )

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1. Nystagmus both eyes slow toward cold, fast to midline Not comatose 2. Both eyes tonically deviate toward cold water Coma with intact Brainstem 3. No eye movement Brainstem injury 4. Movement only of eye on side of stimulus Internuclear ophthalmoplegia Suggests Brainstem structural lesion Cont./ 2. Absence of brain stem reflexes : c. Facial sensation and motor response: i . No corneal reflex (wisp of cotton) i i.No grimacing to deep pressure on nail bed, supraorbital ridge or temporomandibular joint d. Pharyngeal and tracheal reflexes: i . No gag reflex :unreliable test in AAN i i . No cough reflex (ETT-Response to suctioning)

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3. Apnea test : is based on disconnection of the ventilator and the principle of apneic oxygenation It is done only if the patient fulfilled all the previous criteria. Prerequisites (before disconnecting the ventilator): i . Absence of respiratory depressants ii. Core temperature ≥ 36.5 ć iii. SBP ≥ 90 mmHg vi. Euvolemia (option: +ve balance in the previous 6 hours) vii. ABG :(Normal PaCO2 ≥ 40 &PaO2 ≥ 200 mmHg) viii. Notify family

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b. Deliver 100% O2,6 L/min, into the trachea, (option: place a cannula at the level of the carina). c. Connect a pulse oximeter and disconnect ventilator d. Look closely for respiratory movement . e. continuous monitoring of oxygen saturation, ECG, and blood pressure f. An immediate ABG after 8 minutes , and reconnect the ventilator.

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Results of apnoea test: . If respiratory movements are absent and PaCO2 is ≥ 60 mmHg(or ≥20 mmHg above pre-test PaCO2 ), the apnea test is + ve (i.e., the diagnosis of brain death is completed). . If PaCO2 is < 60 mmHg(, the result is indeterminate and repeat with longer time and additional confirmatory test can be considered. . If respiratory movements are observed, the apnea is – ve (i.e., it does not support the diagnosis of brain death) .

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When you have to connect the ventilator and stop the test ? If during the test : . SBP becomes ≤ 90 mmHg . The pulse oximeter indicates significant oxygen desaturation. . Cardiac arrhythmias is present. If the apnea test cannot be completed, repeat it with better patient preparation, or do a cerebral blood flow test. Then a confirmatory test must be performed.

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C) Confirmatory testing: Indications: 1. To complete the diagnosis of BSD. 2. If apnea test is not possible 3. If BS function testing is not possible. Types: . Cerebral angiography . Electroencephalography(EEG is of very limited value for diagnosis of brain death, however it is mentioned in some pediatric brain death protocols). . Transcranial Doppler echography . Somatosensory evoked potentials * These tests are to be repeated between 6-24 hours later to insure irreversibility (No specific time interval) * *Two consultants should perform these tests.

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Clinical diagnosis of pediatric BSD: The same clinical diagnosis for adult ,but change in the time interval between the two tests, and the necessity for two corroborating EEGs or one EEG with corroborating radionuclide angiography . Children of different ages : < one week : interval one week( medico legal reasons) one week - 2 months :48 hours 2- 12 months : 24 hours >1 year : 12 hours

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Regional rules and laws : . There is no standardization of legal determination of brain stem death internationally. * In countries which accept this diagnosis it is used as a part of organ donation programs ( by moving the time of death to an earlier point that facilitates organ transplants, and indeed makes such transplants possible) * Stop the expensive supportive medications in ICU * Other medico legal and social aspects .

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