Brain Death Determination — Lecture

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A Little History...

• Advanced cardiopulmonary support created the awareness of neurologic death
• 1959 - Mollaret and Goulon published “le coma dépassé”
• Foundation for understanding that cessation of neurological function is as important as cessation of cardiorespiratory function for determining death
• 1968 - Harvard Brain Death criteria - set forth clinical standards for the diagnosis of

• Established two categories to declare death: (1) cessation of cardiorespiratory function and (2) BD/DNC
• Early 1980s - Uniform Determination of Death Act
• Legal basis for establishing BD/DNC
• BD/DNC equivalent to cardiac arrest – BD/DNC=death (legally)
• 2020 – World Brain Death Project – consensus guidelines

• BD/DNC is a medical & legal definition
• Does NOT require consent or participation by family/surrogate decision-maker
• Efforts should be made to discuss the patient’s medical condition & the BD/DNC process with family/surrogate decision-makers
• but should NOT delay the process
• If family request to continue somatic support after the declaration
• f BD/DNC:
• Reasonable brief accommodation (typically ≤ 48h) for family to visit

& come to terms prior to discontinuation

• Patient has sustained a catastrophic, permanent brain injury
• Caused by a mechanism known to lead to BD/DNC
• Neuroimaging c/w mechanism & injury severity
• Assessment initiated when clinical exam suggests permanent cessation of all brain functions
• Should wait a "sufficient" amount of time after injury to ensure no potential recovery
• Period based on pathophysiology of brain injury
• Hypoxic-ischemic brain injury – requires min 24h observation after acute injury
• During this period NO sedating drugs given

• Hypothermia: Temperature restored & maintained ≥ 36℃
• If temperature was ≤ 35.5℃ - 24h wait after rewarming to ≥ 36℃
• Hypotension:
• Pts ≥ 18 years maintain SBP ≥ 100 mmHg & MAP ≥ 75 mmHg
• Pediatric - maintain SBP & MAP ≥ 5th percentile for age
• If baseline BP varies significantly from age-based normal range, target an SBP & MAP that approximate pt baseline
• Intoxication: Exclude metabolic derangements, intoxication, or CNS depressing medications
• Consider renal or hepatic dysfunction, body mass index, age

• Two clinicians perform a separate & independent examination
• Pediatric patients 12h minimum separating two exams is required
• No minimum in adult
• Documentation of each required

• Spinal reflexes are excluded as motor responses
• Deep tendon reflexes
• Plantar reflexes
• Triple flexion of the legs
• Toe flexion/extension on plantar stimulation

• Age ≥ 18: At least one test
• Pediatric: Two apnea tests
• 1 after each BD/DNC clinical exam
• Adjust ventilator to achieve normal PaCo2 (35-45 mm Hg) & pH (7.357.45)
• If CO2 retainer – adjust to meet patient's baseline
• Preoxygenate 100% Fio2 for 10min (aiming for Pao2 > 200 mm Hg)
• Check ABG to establish baseline pH, Pao2 , Paco2 within parameters
• Fully disconnect the patient from the ventilator and start timer
• Provide apneic oxygenation
• Monitor closely for respiratory movements for 8-10 minutes

• If no respiratory drive after 8-10 minutes - serial ABG’s (~ every 2min)
• Continue until ABG results c/w the following criteria:
• No respirations or effort occurs and
• Arterial pH <7.30 and
• Paco2 ≥60 mm Hg & ≥20 mm Hg above pre-apnea test baseline level (or chronic baseline level in CO2 retainers)
• Terminate apnea test for:
• Spontaneous respirations
• Hemodynamic instability or hypoxemia:
• SBP ≤100 mm Hg or MAP ≤75 mm Hg in adults, or SBP or MAP ≤5th percentile for age in children (despite pressor titration)
• O2 sat < 85%
• Cardiac arrhythmia with hemodynamic instability

• Pregnancy:
• Not a contraindication to BD/DNC
• BD/DNC should be assessed & diagnosed
• After BD/DNC determination - multidisciplinary team should discuss with pt decision-makers the risks/benefits to the fetus of continuing maternal organ support
• Primary Infratentorial/Posterior Fossa Injury:
• Need to ensure no retained supratentorial function (whole brain death) before BD/DNC eval ▪ Demonstration the infratentorial/posterior fossa process has led to catastrophic supratentorial injury on conventional neuroimaging study