Presentation on theme: "Emergency Lecture Series Emergency Lecture Series: Brain Death and Organ Donation Robert Altman, R5 McGill Neurology August 10 th 2011."— Presentation transcript:
Emergency Lecture Series Emergency Lecture Series: Brain Death and Organ Donation Robert Altman, R5 McGill Neurology August 10 th 2011
Outline Pre-Test Brain death exam in context of “prognostication” skills Definition and standardized exam for brain death – Canadian + Transplant Quebec guidelines – AAN guidelines (recently updated 2010) Organ donation; Transplant Quebec Neuro-otology reinforcement Post-test
Pre-Test 1.How many criteria are there to establish NDD? 2.Explain which side the MLF is lesioned if I instil cold water into the pt’s L ear and you get this response. – Is this compatible with NDD? 3.What are the apnea test parameters? 4.What are the 2 “ancillary tests” that should be used when clinical grounds for NDD cannot be established? Transcranial doppler Conventional angio MRA/I Tc99HMPAO nuc. med. Scan EEG SSEP
Vancouver, 2003 In all Canadian provinces and territories, the legal definition of brain death is “according to accepted medical practice.” – Practices are largely determined by individual hospitals or regions. – Guidelines established by the Canadian Congress Committee on Brain Death in 1986 and the Canadian Neurocritical Care Group in 1997 initiated clarification of the criteria, but have not led to uniform practice.
“Severe Brain Injury to Neurological Determination of Death,” held in Vancouver from 9 to 11 April 2003, was to initiate the development of a national agreement on the processes of care, commencing with severe brain injury and culminating with NDD
Overarching Recommendations NDD = Neurological Determination of Death – Confirmation of NDD = legal time of actual death Even if there is intact cardiac functions (assumed this will be temporary, and non-sustained) No clear medical basis for 2 independent exams – Can be performed by 2 MD’s concurrently – If performed at different times, a full clinical examination, including apnea testing, must be performed at each determination – No fixed interval of time is recommended for the second determination, except where age-related criteria apply
NDD (Neurological Determination of Death) Aetiology established that can cause irreversible death No confounders Deep coma – Absence of motor responses to stimuli, no spontaneous or abnormal movements (dyskinesia, posturing) or seizures – N.b. spinal reflexes may exist Absence of brainstem reflexes – No spontaneous breathing during apnea test Infants (≥30d and <1yr); repeat exam recommended
R/O These Confounders 1.Unresuscitated shock 2.Hypothermia (core temperature <34 °C) 3.Severe metabolic disorder capable of causing a potentially reversible coma – Glucose, E+ (PO4, Ca, Mg), IEM, LFT, creatinine, BUN Should correct any abnormality that could possibly influence decision 4.Peripheral nerve / muscle or NMJ blockade 5.Drug intoxications – ETOH, barbituates, sedatives, hypnotics Should calculate 5 ½ lives to clear drug; longer if cooled. – NB therapeutic levels of AED, sedatives or analgesics do not preclude the diagnosis
Irreversible Cause of Death Neurological assessments may be unreliable in the acute post-resuscitation phase after cardiorespiratory arrest. In cases of acute hypoxic-ischemic brain injury, clinical evaluation for NDD should be delayed for 24 h subsequent to the cardiorespiratory arrest or an ancillary test could be performed. Core temperature MUST be ≥ 34°C to proceed with formal testing. – Central blood, rectal or esophageal–gastric – Previously was 32.2°C
Brain Death Exam Brainstem – Pupils ≥4-9mm, unresponsive to light* (enquire about Rx given) – Corneals Movement of jaw or lids excludes NDD – Vestibulo-ocular responses OCR (Doll’s) – Caution if trauma Cold calorics – Pharyngeal Stimulate posterior pharynx Suction the ETT Depress larynx, swallow reflex – Apnea test
Doll’s Eyes Normal response = eyes always gaze up towards roof Rapid, but steady movements and observe for direction of gaze – Activates vestibular system ipsilateral to head thrust (same principal for HIT) Communicates with contralateral horizontal gaze center (CN VI) “orchestrating” the action of the eyes Simultaneously dampens contralateral vestibular tone, etc. Left vestibular tone L CN VI (HGC)Right vestibular tone R CN VI (HGC) Turn to left+--+ Turn to right-++-
Cold Calorics 30° to the horizontal Minimum of 50cc of ice cold water into the inner ear canal – Ensure no perforated tympanic membrane before instilling water – Use kidney basin, prop up beside ear Start observing for eye deviation rapidly; eye movements should be absent for 1 minute Minimum of 5 minutes before evaluating contralateral side
Cold Caloric Testing Cold Caloric Testing Vestibulo-Ocular Reflex (VOR) Attenuates resting state vestibular tone Pearl: COWS mneumonic implies intact cortex (frontal eye fields). If on coma / sedated, will not get corrective nystagmus.
Warm Caloric Testing Warm Caloric Testing ( Rarely done in neurology...) Increases resting state vestibular tone
Apnea Test Temperature ≥34°C, SBP >90mmHg (adults), euvolemia Pre-oxygenate with 100% FiO 2 for 10-15 min (PaO2 >200mmHg) Baseline ABG – PH 7.35-7.40 – PC0 2 40+/- 5 mmHg Disconnect ventilator – T-piece with CPAP at 10 CM H 2 0, deliver FiO2 at 10L/min or insert catheter into ETT and deliver FiO2 at 6L/min (at carina) Observe for respiratory efforts x 8-10 min Repeat ABG at 8-10 min and reconnect ventilator – Test + if PaCO 2 ≥60mmHg and rise in 2mmHg/min (≥ 20mmHg) above baseline levels and PH ≤7.28 No respiratory efforts demonstrated Stop if HD instability or desaturation occurs
Apnea Test (if lung disease) If severe lung disease – Caution must be exercised in considering the validity of the apnea test – If in the physician’s judgment, there is a history suggestive of chronic respiratory insufficiency and responsiveness to only supranormal levels of carbon dioxide, or if the patient is dependent on hypoxic drive. – If the physician cannot be sure of the validity of the apnea test, an ancillary test should be administered.
Ancillary Testing The term “ancillary” should be understood to mean an alternative test to one that otherwise, for any reason, cannot be conducted. – No longer called “confirmatory” or “supplemental” – Different connotations Gold standard = global absence of intracerebral blood flow (only 2 tests support) – Cerebral angiography or radio-isotope scan
Special Circumstances Children ≥ 1 yr (including adolescents) – Same criteria – Mandates a second exam No fixed time interval – Physician qualified with working with critically ill children (i.e, not an adult neurology resident doing an elective at the MCH) 30 days to 1 year old (corrected for GA) – Minimum clinical criteria = OCR (more reliable due to external auditory canal anatomy) – Repeat exam recommended by another physician / at another time (lack of collective experience and research on brain death in this age group) – If uncertain or confounders factoring in, extend time interval or perform ancillary testing – Specialists with skill and knowledge in management of infants with severe brain injury
NDD recommendations for term newborns aged <30d Standards apply for all those >36wks gestation* NDD is clinical – Absence of OCR and suck reflex – Temp (core) ≥ 36°C Min time from birth to first determination is 48h 2 determinations required, minimum interval 24h Ancillary testing: – Should be performed when any of the minimum clinical criteria cannot be established or confounding factors remain unresolved “specialists with skill and knowledge in the management of newborns with brain injury and the determination of death based in neurological criteria.”
Other tidbits NDD can be determined (in adults) – any physician licensed by the college of physicians and surgeons or licensing authority in that jurisdiction. – excludes physicians who are only on an educational register. – does not require a particular level of specialty certification; – nonspecialists can declare NDD if they have the requisite skill and knowledge.
Organ Donation 3 pronged approach – Environment Caring attitude; be open and honest Ask if family members around, or if there is a family spokesperson Take family to private room Offer pastoral services Offer phone, tissue, etc. – Knowledge Assess loved-ones comprehension of the situation Emphasize irreversibility of brain death Repeat the information as many times as necessary Grant enough time to assimilate the new knowledge – The Question (at a future time-point) Verify wished of deceased (organ donor signature on RAMQ card) Be attentive to apprehension; answer questions +++ Offer possibility of communication with T-Q Emphasize possibility of giving the gift of life to another
Resources http://www.quebec-transplant.qc.ca CMAJ: Brain arrest: the neurological determination of death and organ donor management in Canada AAN 2010 Clinical practice guidelines on brain death – Including PowerPoint presentation
Post-Test 1.How many criteria are there to establish NDD? (4) Death by something known to be able to kill you. No confounders. Deep coma with absent motor responses; except local spinal reflexes. Brainstem death: absent corneals, gag, VOR, pupils midposition and areactive, + apnea test. 2.Explain which side the MLF is lesioned if I instil cold water into the pt’s L ear and you get this response. – Is this compatible with NDD? 3.What are the apnea test parameters? 4.What are the 2 “ancillary tests” that should be used when clinical grounds for NDD cannot be established? Transcranial doppler Conventional angio MRA/I Tc99HMPAO nuc. med. scan EEG SSEP
Vestibular apparatus Vestibular nucleus PPRF VI “HORIZONTAL GAZE CENTER” Lateral rectus MLF = Medial Longitudinal Fasciculus Medial rectus III Normal Vestibular Physiology
JGH ER, July 2011 65M, felt abrutly unwell one evening, then literally “flung off his couch,” illusion of spinning around his room. – a/w nausea and vomiting, no other craniobulbar symptoms. Exam demonstrates a right beating nystagmus in primary gaze, worsened on R gaze, dampened on L gaze, but nontheless present... Remainder of exam normal (including TOS).
Vestibular nucleus PPRF VI L Vestibular Neuronitis Dampened Slow tonic deviation L Left FEF PPRF VI Rules 1.Hypofunctioning implies fast phase away (vestibular neuronitis) OR eyes tonically drift to impaired side 2.Hyperfunctioning (BPPV), fast phase towards dysfunctional vestibular apparatus III Vestibular apparatus slow fast slow L R
Vestibular apparatus Vestibular nucleus PPRF VI R Irritative phase of neuritis Irritated Slow tonic deviation L Slow L FEF PPRF VI Rules 1.Hyperfunctioning (BPPV), fast phase towards dysfunctional vestibular apparatus III fast L R