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Concept
- Whole-brain criteria: irreversible loss of ALL brain function including brainstem
- Most US states + many countries
- Legally + ethically equivalent to cardiopulmonary death
History
- 1968 Harvard criteria (initial)
- 1981 Uniform Determination of Death Act (US)
- 2010 AAN adult guidelines
- 2011 pediatric guidelines
- 2023 AAN consensus (combined adult + pediatric â latest)
Prerequisites Before Determining
Establish Irreversibility
- Known etiology (history, imaging, exam)
- No reasonable possibility of recovery
Exclude Confounders
- Hypothermia: core temperature ⥠36°C
- Drug intoxication / sedatives: clearance, levels if available
- Neuromuscular blockade: train-of-four
- Severe metabolic / electrolyte / acid-base disturbance: correct extremes
- Severe endocrine (myxedema, adrenal crisis)
- Severe hypotension: SBP ⥠100 mmHg (vasopressors OK)
- Adequate ventilation: PaO2 ⥠200, PaCO2 35-45 baseline
1. Coma
- Unresponsive
- No purposeful movements
- No grimacing
- No posturing
- Spinal reflexes can be present (donât exclude)
2. Absent Brainstem Reflexes
- Pupillary: bilateral fixed, mid-position or dilated (4-9 mm)
- Corneal: no blink
- Oculocephalic (dollâs eyes): absent (or NOT done if C-spine)
- Oculovestibular (cold calorics): absent (no eye movement with 50 mL ice water in each ear, intact TM)
- Gag: absent
- Cough (tracheal suction): absent
- Jaw jerk: absent (V â VII)
- Facial grimace to noxious stimulus: absent
3. Apnea Test
- Pre-oxygenate 100% FiO2 Ã 10 min
- Confirm baseline PaCO2 35-45 mmHg
- Disconnect ventilator (or PSV with no rate)
- Provide O2 (cannula in trachea or CPAP)
- Observe for 8-10 min for respiratory effort
- ABG at end
- Positive (confirms apnea):
- PaCO2 ⥠60 mmHg, OR
- PaCO2 ⥠20 mmHg above baseline
- NO respiratory effort observed
- Abort if: hemodynamic instability, hypoxia, arrhythmia
Number of Examinations
- 1 in adults (most US states)
- 2 in children
- Some institutions require 2
Examiner Qualifications
- Trained physician (neurologist, neurosurgeon, intensivist, etc.)
- Specific certification often required
When to Use
- Apnea test contraindicated (severe hypoxia, hypotension)
- Confounders cannot be eliminated
- Clinical exam cannot be fully completed (facial trauma, severe c-spine, drugs)
- Per institutional policy
- Family request
Tests
- EEG: electrocerebral silence (< 2 ΌV) for ⥠30 min
- Cerebral blood flow:
- Conventional 4-vessel angiography (gold standard historically)
- Radionuclide cerebral perfusion scan (HMPAO)
- CTA with brain death protocol
- MR angiography
- Transcranial Doppler (TCD): oscillating flow, systolic spikes
- SPECT, PET: no perfusion
Spinal Reflexes
- Can persist after brain death
- âLazarus signâ (complex spinal movements)
- Triple flexion, plantar reflex
- Do NOT preclude diagnosis
Pediatric
- Different age-specific protocols
- 2 examinations + 2 apnea tests
- Specific intervals based on age
- Ancillary tests recommended
Newborns + Premature
- Special considerations
- Higher thresholds for caution
Therapeutic Hypothermia
- Wait ⥠24 hr after rewarming
- Drug confounders
Ethical Framework
- Separation of declaration from organ donation
- Family consent (US opt-in)
- Specific consent for procedures
Donation After Brain Death (DBD)
- After formal declaration
- Maintenance of physiology for organ recovery
Donation After Circulatory Death (DCD)
- Different category
- After cardiac death
- Usually withdrawn care + waiting period
- Specific protocols
Brain Death Maintenance
- Hemodynamic support (vasopressors, fluids)
- Ventilation
- Hormone replacement (thyroid, vasopressin, methylpred)
- Glucose control
- Temperature
- Coordination with OPO (organ procurement organization)
Communicating with Families
Approach
- Clear, compassionate language
- âBrain deathâ = death (not âbrain dead but aliveâ)
- Mechanical ventilation maintains organ function temporarily
- Explain examination + results
- Address questions
- Consider cultural/religious factors
Religious Objections
- Some traditions (Orthodox Judaism, some Islamic, etc.) may not accept brain death
- State laws vary (NY, NJ allow religious accommodation)
- Ethics consultation
Disorders of Consciousness (DOC) Spectrum
Coma
- Eyes closed
- Unarousable
- No awareness
Vegetative State (UWS â Unresponsive Wakefulness Syndrome)
- Eyes open
- Sleep-wake cycles
- No awareness
- No purposeful response
- Brainstem reflexes intact
- Acute â persistent (1 mo) â permanent (3 mo non-traumatic, 12 mo traumatic)
Minimally Conscious State (MCS)
- Some inconsistent signs of awareness
- Visual tracking, simple commands (intermittent)
- Better prognosis than UWS
- Emergence to communication possible
Locked-In Syndrome
- Awake + aware
- Quadriplegic + anarthric
- Preserved vertical eye movements + blinking
- Ventral pontine lesion (basilar artery occlusion)
- Pseudocoma â easy to mistake
Akinetic Mutism
- Awake, no movement/speech
- Bilateral frontal lobe lesions
Covert Consciousness
- Apparent UWS but fMRI/EEG shows awareness
- Command following paradigms
- âCognitive-motor dissociationâ
- Important to detect (treatment implications)
𩺠åºééæ¥
- Brain death = irreversible loss of ALL brain function including brainstem
- 3 criteria: irreversible coma + absent brainstem reflexes + apnea
- Exclude confounders: hypothermia, drugs, NMB, hypotension, metabolic
- Apnea test: PaCO2 ⥠60 or â ⥠20 from baseline with no breathing
- Ancillary: EEG silence, cerebral blood flow studies, TCD
- Spinal reflexes can persist â donât exclude
- DOC spectrum: coma â UWS â MCS â emergence
- Locked-in: pseudocoma, awareness intact