Brain death

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"brain death" determination criteria

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Brain Death

Definition

Brain death is defined as the irreversible cessation of all functions of the entire brain, including the brainstem. It is legally and medically equivalent to death, even when cardiac and pulmonary function are maintained by artificial means. This concept was first formally described in 1959 by French neurologists Mollaret and Goulon, who termed it coma dépassé ("a state beyond coma"). It was given its modern clinical framework by the Harvard Ad Hoc Committee in 1968, partly in the context of the first cardiac transplant performed by Christiaan Barnard in 1967.

Adams and Victor's Principles of Neurology, 12th Ed.
Plum and Posner's Diagnosis and Treatment of Stupor and Coma

Common Causes

Brain death is relatively uncommon because the brainstem is highly resilient. When it does occur, the most frequent causes are:

Severe traumatic brain injury (TBI)
Aneurysmal subarachnoid hemorrhage
Massive intraparenchymal hemorrhage
Anoxic-ischemic brain injury (e.g., prolonged cardiac arrest)
Severe cerebral edema from any cause
Bradley and Daroff's Neurology in Clinical Practice

Prerequisites Before Clinical Examination

Before proceeding with brain death evaluation, all potentially reversible/confounding conditions must be excluded:

Condition	Requirement
Hypothermia	Core temperature must be ≥36°C
Drug intoxication	No CNS depressants (sedatives, opioids, barbiturates, neuromuscular blockers)
Metabolic/electrolyte disturbance	No severe acid-base, electrolyte, or endocrine abnormalities
Known irreversible cause	Confirmed by history and neuroimaging

Brain death should not be determined within hours of emergency department evaluation or transfer, as early history is often fragmentary and medication history uncertain.

Bradley and Daroff's Neurology in Clinical Practice

Clinical Criteria for Brain Death

Three core requirements must all be met:

Absence of all cerebral functions (deep coma)
Absence of all brainstem functions (including spontaneous respiration)
Irreversibility of the state

1. Absence of Cerebral Function

Deep, unresponsive coma
No spontaneous movements
No motor or vocal response to visual, auditory, or cutaneous stimulation
Note: Spinal reflexes (deep tendon reflexes, slow plantar flexion) may persist and do NOT exclude brain death
Decerebrate or decorticate posturing is considered incompatible with brain death (reflects functioning brainstem centers); proceed cautiously if present

2. Absence of Brainstem Reflexes

Examine all of the following - all must be absent:

Reflex	Finding in Brain Death
Pupillary response to light	Absent bilaterally; pupils fixed at 4-6 mm (mid-position to dilated); constricted pupils suggest opioid effect
Corneal reflex	Absent bilaterally
Oculocephalic reflex (doll's eyes)	Absent
Oculovestibular reflex (caloric testing)	No eye movement after ice-water irrigation of each ear (head at 30°); observe 1 minute per side, wait ≥5 min between sides
Facial motor response to pain	No grimacing to deep pressure at temporomandibular joints, supraorbital notch, fingernail beds
Gag reflex	Absent to posterior oropharyngeal stimulation
Cough reflex	Absent to deep tracheal suctioning to carina
Spontaneous respirations	Absent

3. Apnea Test

The apnea test demonstrates irreversible destruction of medullary respiratory centers:

Preoxygenate with 100% FiO2 for several minutes (creates alveolar O2 reservoir)
Disconnect the ventilator; provide passive O2 via cannula or CPAP
Allow arterial PaCO2 to rise to ≥60 mmHg (CO2 rises ~2.5 mmHg/min at normothermia)
No spontaneous breathing = positive apnea test (confirms brain death)
Confirm with arterial blood gas showing adequate PaCO2 level

Risks: hypotension, hypoxemia, cardiac arrhythmias, lung barotrauma (generally minimal per AAN 2010 guidelines).

Cannot perform apnea test if: paralytic drugs present, Guillain-Barré syndrome, or patient is hemodynamically unstable.

Adams and Victor's Principles of Neurology
Bradley and Daroff's Neurology in Clinical Practice

Ancillary (Confirmatory) Tests

In most countries including the United States, confirmatory tests are not required if the full clinical examination can be completed. They are used when clinical examination is incomplete or confounded.

Test	Finding in Brain Death
EEG	Electrocerebral silence (electrocerebral inactivity) - no cerebral electrical activity; must follow ACNS technical standards
Radionuclide cerebral blood flow scan	Absent intracranial perfusion ("hollow skull" sign)
CT/MR angiography	Absent intracranial blood flow
Transcranial Doppler	Absent or reverberating flow
Atropine test	No tachycardia after atropine injection (loss of medullary vagal innervation)

Important EEG caveat: Reversible electrocerebral silence can occur with drug overdose, hypothermia, and immediately post-resuscitation - EEG must be interpreted in clinical context.

Bradley and Daroff's Neurology in Clinical Practice

Ancillary Findings

Diabetes insipidus is common (loss of posterior pituitary/hypothalamic function), though its absence does not exclude brain death
Lazarus sign: Dramatic spinal-cord-mediated movements (arms rising, hands coming together at midline, opisthotonos, head-turning) may occur spontaneously during apnea testing or after ventilator disconnection. These are spinally mediated - they do NOT indicate brain activity and should not be confused with recovery. Families should ideally not witness terminal ventilator disconnection for this reason.
Adams and Victor's Principles of Neurology
Plum and Posner's Diagnosis and Treatment of Stupor and Coma

Number of Examiners and Repeat Examinations

In the U.S., the AAN guidelines (1995, updated 2010) govern the process
Most protocols require at least one physician (typically a neurologist or neurosurgeon) to perform a complete examination; some states require two separate examinations
An observation period between examinations is standard (varies by institution and etiology)

Legal and Ethical Dimensions

Brain death is accepted in 48 U.S. states and incorporated into the Uniform Determination of Death Act (UDDA)
The concept underpins organ donation: without it, viable organs would be lost from otherwise hopeless patients
Religious/cultural objections: Some Orthodox Jewish communities and certain Asian cultures (historically Japan, which only recently legalized brain death determinations) reject the concept. New Jersey law requires declaration of cardiac death if the family objects on religious grounds; New York requires "reasonable accommodation" but does not preclude a neurological determination
Philosophical objections include reported cases of prolonged somatic survival (including a 20-year survival case after meningitis and deliveries of live infants from brain-dead mothers), which challenge the argument that the brain provides essential "somatic unity"
Plum and Posner's Diagnosis and Treatment of Stupor and Coma
Adams and Victor's Principles of Neurology

Pediatric Considerations

Brain death criteria in children (especially neonates) differ from adults - longer observation periods and additional confirmatory testing are typically required. Dedicated pediatric guidelines exist (separate from the AAN adult guidelines).

Summary of Key Criteria (AAN Framework):

Irreversible coma with known cause + all brainstem reflexes absent + positive apnea test (PaCO2 ≥60 mmHg, no spontaneous breaths) = Brain Death

Brain death

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"brain death" determination criteria guidelines

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Brain Death (Death by Neurologic Criteria)

Definition

Brain death - formally called death by neurologic criteria (BD/DNC) - is the irreversible cessation of all functions of the entire brain, including the brainstem. It is legally and medically equivalent to death, even when cardiopulmonary function is sustained artificially.

Historical milestones:

1959 - Mollaret & Goulon described coma dépassé ("a state beyond coma") in patients with destroyed brains kept on ventilators
1968 - Harvard Ad Hoc Committee (the "Beecher Committee," which included R.D. Adams) formally defined brain death and established clinical criteria; this followed Christiaan Barnard's first cardiac transplant in 1967 and the need to define death for organ retrieval
1981 - The Uniform Determination of Death Act (UDDA) in the U.S. codified brain death as legal death
1995/2010 - American Academy of Neurology (AAN) published and updated adult guidelines
2023 - A landmark AAN consensus guideline unified pediatric and adult criteria in a single document (Greer et al., Neurology 2023; PMID 37821233)

Common Causes

Brain death is relatively uncommon because the brainstem is highly resilient. When it occurs, the most frequent causes are:

Severe traumatic brain injury (TBI)
Aneurysmal subarachnoid hemorrhage
Massive intraparenchymal hemorrhage
Anoxic-ischemic brain injury (e.g., prolonged cardiac arrest)
Severe cerebral edema from any cause

- Bradley and Daroff's Neurology in Clinical Practice

Three Core Clinical Requirements

All three must be simultaneously satisfied:

Irreversible coma with an established, known cause

Absence of all brainstem reflexes

Positive apnea test (no breathing at PaCO₂ ≥ 60 mmHg)

Step 1: Prerequisites (All Must Be Met)

Before any clinical examination, the following confounders must be excluded:

Prerequisite	Threshold
Core temperature	≥ 36°C (hypothermia can mimic brain death)
Systolic blood pressure	≥ 100 mmHg
Sedatives / opioids / neuromuscular blockers	None present or cleared
Severe metabolic/electrolyte disturbance	Absent
Cause of coma	Established by history + neuroimaging

Brain death should not be determined within hours of ED arrival or transfer - early medication and history are often incomplete. Treatment attempts (ICP-lowering therapies, ventriculostomy, surgical decompression) should have been made before concluding the injury is unsurvivable.

- Bradley and Daroff's Neurology in Clinical Practice; Miller's Anesthesia, 10e

Step 2: Neurological Examination

Absence of Cerebral Function

Deep, unresponsive coma - no spontaneous movement, no response to visual, auditory, or cutaneous stimuli
No motor or vocal responses to any noxious stimulation
Spinal reflexes may persist (deep tendon reflexes, plantar flexion) - these do NOT exclude brain death
Decerebrate or decorticate posturing is considered incompatible with brain death (implies functioning brainstem centers); proceed cautiously if present

Brainstem Reflex Examination (All Must Be Absent)

Reflex	Technique	Finding
Pupillary light reflex	Bright light to each eye	Fixed, non-reactive pupils (typically 4-6 mm); constricted pupils suggest opioid effect
Corneal reflex	Cotton wisp to cornea	No blink bilaterally
Oculocephalic reflex	Rapid head rotation (doll's eyes)	Eyes move with head (absent normal response)
Oculovestibular reflex	50 mL ice water to each ear; head at 30°; observe 1 min; wait ≥5 min between sides	No eye movement in either direction
Facial pain response	Deep pressure at TMJ condyles, supraorbital notch, fingernail beds, sternal rub	No grimacing
Gag reflex	Stimulate posterior oropharynx / tonsillar pillars	Absent
Cough reflex	Suction catheter to level of carina	Absent
Spontaneous respirations	Direct observation	None

- Adams and Victor's Principles of Neurology, 12th Ed.; Bradley and Daroff's Neurology in Clinical Practice

Step 3: Apnea Test

The apnea test is the definitive demonstration that medullary respiratory centers are destroyed.

Procedure:

Confirm prerequisites: SBP ≥ 100 mmHg, PaO₂ ≥ 200 mmHg on 100% FiO₂, PaCO₂ 35-45 mmHg (normocapnia baseline)
Preoxygenate with 100% O₂ for 10 minutes
Disconnect ventilator; provide passive O₂ via insufflation catheter to carina at 6 L/min (or CPAP valve + T-piece)
Observe for any breathing effort (chest expansion, abdominal excursion, gasping) for 8-10 minutes
Obtain arterial blood gas

Positive apnea test (confirms brain death):

No respiratory effort AND
PaCO₂ ≥ 60 mmHg, OR rise of ≥ 20 mmHg above a normal baseline

Physiologic basis: CO₂ rises ~2.5 mmHg/min at normothermia (slower if hypothermic). This level is a powerful stimulus to intact medullary chemoreceptors - the absence of any response confirms medullary failure.

Complications and contraindications: Hypotension, hypoxemia, cardiac arrhythmias, barotrauma may occur. If the test cannot be safely completed (hemodynamic instability, inability to reach target PaCO₂), ancillary testing is required. Peripheral causes of respiratory failure (neuromuscular blockers, Guillain-Barré syndrome) must be excluded.

- Adams and Victor's Principles of Neurology; Bradley and Daroff's Neurology in Clinical Practice

Ancillary (Confirmatory) Tests

In the U.S. and most countries, confirmatory tests are not required when the full clinical examination (including apnea test) is completed. They are used when:

Clinical examination is incomplete (e.g., severe facial trauma precluding reflex testing)
Confounders cannot be fully excluded
Apnea test cannot be safely performed

Test	Finding in Brain Death
EEG	Electrocerebral silence (no potentials > 2 µV over 30 min; min. 8 scalp electrodes); reversible causes (drug OD, hypothermia) must be excluded
Radionuclide cerebral blood flow scan	Absent intracranial perfusion ("hollow skull" / "empty light bulb" sign)
CT angiography / MR angiography	Absent intracranial arterial flow
Transcranial Doppler (TCD)	Absent or reverberating/oscillating flow pattern
SSEP / BAEP	Loss of cortical SSEP responses (N20 absent); absent BAEP waves III-V
Atropine test	No tachycardia after IV atropine (loss of medullary vagal innervation)

- Bradley and Daroff's Neurology in Clinical Practice; Miller's Anesthesia, 10e

The 25-Point Checklist (Bradley & Daroff Framework)

The examination can be organized as a structured checklist covering:

8 prerequisites (coma cause known, neuroimaging, no drug effect, no paralytic, no metabolic disturbance, normothermia, hemodynamic stability)
9 brainstem reflex checks
8 apnea test steps (including pre-oxygenation, baseline ABG, disconnection, observation, post-ABG confirmation)

Notable Phenomena

Lazarus Sign

Dramatic spinally mediated movements that can occur during or after apnea testing / ventilator disconnection:

Arms elevating and hands coming together at the midline ("as if to pray")
Opisthotonos with chest expansion simulating a breath
Head-turning, shoulder shrugging
Posturing-like movements

These are spinal cord reflexes - they do not indicate brain activity or recovery. Families should ideally not be present when the ventilator is discontinued, as these movements are emotionally disturbing even to experienced clinicians.

- Adams and Victor's Principles of Neurology (Lazarus sign named by Ropper, 1984)

Diabetes Insipidus

Common in brain death (loss of hypothalamic/posterior pituitary function), but its absence does not rule out brain death.

Special Circumstances (2023 AAN Guideline Updates)

The 2023 unified AAN consensus guideline (PMID 37821233) provided 85 recommendations addressing:

ECMO patients - guidance on BD/DNC evaluation during extracorporeal membrane oxygenation
Targeted temperature management (TTM) - how to time and interpret examination after therapeutic hypothermia
Primary infratentorial injury (posterior fossa lesions) - additional considerations when the brainstem is the primary injury site
Pediatric criteria - integrated with adult criteria; children (especially neonates) require longer observation periods and often ancillary testing

Qualifications and Process

Physician must have adequate training and understanding of BD/DNC principles
Most U.S. institutions require at least 1-2 examinations by a qualified physician (neurologist, neurosurgeon, or intensivist)
An institutionally approved protocol must be followed
Significant variability exists internationally; minimum global standards are recommended

Legal, Ethical, and Cultural Dimensions

Brain death is legally recognized death in 48 U.S. states and most countries
New Jersey: Requires declaration of cardiac death if family objects on religious grounds
New York: Requires "reasonable accommodation" for religious/moral objections but does not preclude neurological determination
Japan: Only recently legalized brain death determinations for organ donation
Orthodox Jewish communities and some Asian cultures historically reject the concept
Philosophical objections note: documented cases of prolonged somatic survival (including a 20-year case post-meningitis) and delivery of live infants from brain-dead mothers challenge the argument that the brain is essential for "somatic unity"
Beecher's original utilitarian argument - that organs should be retrieved from the "hopelessly comatose" - established the cultural link between disorders of consciousness and organ donation, a linkage that continues to generate ethical debate

- Plum and Posner's Diagnosis and Treatment of Stupor and Coma; Adams and Victor's Principles of Neurology

Sources:

Adams and Victor's Principles of Neurology, 12th Ed., pp. 378-383
Bradley and Daroff's Neurology in Clinical Practice, Ch. 6, pp. 90-91
Plum and Posner's Diagnosis and Treatment of Stupor and Coma, p. 784-785
Miller's Anesthesia, 10e, pp. 12045-12046
Greer DM et al. "Pediatric and Adult Brain Death/Death by Neurologic Criteria Consensus Guideline." Neurology 2023. PMID 37821233

Confounders

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Confounders of Brain Death

A confounder in brain death is any reversible condition that can produce the full clinical picture of brain death - deep unresponsive coma, absent brainstem reflexes, apnea - without the brain actually being irreversibly destroyed. Every single confounder must be excluded before the examination is valid. If any doubt remains, the examination must be deferred or ancillary testing used.

The Major Confounders

1. Hypothermia

Why it confounds: Severe hypothermia profoundly depresses all CNS activity, including brainstem reflexes and respiratory drive. It can produce electrocerebral silence on EEG and absent brainstem reflexes that are entirely reversible on rewarming. Cases of full neurological recovery from apparent brain death caused by hypothermia are well documented.

Threshold: Core temperature must be ≥ 36°C before assessment. (Some older criteria used ≤ 32°C as the threshold for concern; current guidelines use ≥ 36°C as the minimum acceptable temperature for examination.)

Practical note: In post-cardiac arrest patients who have undergone targeted temperature management (TTM/therapeutic hypothermia), the brain death examination must be deferred until full rewarming and drug clearance - the 2023 AAN Consensus Guideline specifically addresses this scenario.

- Bradley and Daroff's Neurology in Clinical Practice

2. CNS-Depressant Drug Intoxication

This is the most clinically important confounder. Multiple drug classes can suppress all brainstem reflexes and respiration to a degree that perfectly mimics brain death.

Drugs of Concern

Drug Class	Examples	Key Features
Barbiturates	Phenobarbital, pentobarbital, thiopental	Classically cited; suppresses brainstem reflexes and causes isoelectric EEG; most dangerous confounder
Benzodiazepines	Diazepam, midazolam, lorazepam	Common ICU sedatives; can accumulate with renal/hepatic impairment
Opioids	Morphine, fentanyl, propofol	Opioids cause miosis (constricted pupils) - a direct clue; high-dose propofol can cause electrocerebral silence
Other sedative-hypnotics	Chloral hydrate, meprobamate	Less common but documented
Tricyclic antidepressants	Amitriptyline	Reversible brain death from amitriptyline overdose has been reported in the literature
Alcohol	Ethanol	High levels suppress brainstem function
Antiepileptics	Valproate, high-dose phenytoin	Can contribute at toxic levels

Clue on examination: Constricted (miotic) pupils in apparent brain death should raise immediate suspicion of opioid or other miotic drug effect - pupils in true brain death are fixed and mid-position to dilated (4-6 mm), never constricted.

Management: Allow five half-lives in a patient with normal hepatic and renal function before the examination. In patients with impaired clearance (renal failure, hepatic failure, hypothermia), half-lives are dramatically prolonged and clearance cannot be assumed. Toxicology screening of serum and urine is mandatory when drug or alcohol intoxication could plausibly have contributed.

- Bradley and Daroff's Neurology in Clinical Practice; Adams and Victor's Principles of Neurology

3. Neuromuscular Blocking Agents (NMBAs)

Why it confounds: NMBAs paralyze all motor responses - including facial grimacing, extremity movements, and respiratory muscles - making the motor exam and apnea test completely unreliable. They do not affect brainstem reflexes directly, but a paralyzed patient cannot demonstrate any motor response to noxious stimuli.

Detection: The absence of paralytic effect must be confirmed with a peripheral nerve stimulator (train-of-four stimulation) - clinical observation alone is insufficient.

Management: Allow full clearance (again, five half-lives under normal clearance; longer with impairment). Do not perform the brain death examination with any residual neuromuscular blockade.

- Bradley and Daroff's Neurology in Clinical Practice

4. Severe Metabolic and Electrolyte Disturbances

Several metabolic derangements can suppress brainstem and cortical function sufficiently to mimic brain death:

Disturbance	Mechanism
Severe hyponatremia	Cerebral edema from osmotic shifts
Severe hypernatremia	Hyperosmolar neuronal dysfunction
Hypoglycemia	Substrate deprivation of neurons
Hyperglycemia / hyperosmolar state	Osmotic neuronal dysfunction
Hypercalcemia	Neuromuscular and CNS depression
Hypophosphatemia	Encephalopathy
Severe hepatic encephalopathy	Hyperammonemia, cerebral dysfunction
Severe uremia	Uremic encephalopathy
Severe acid-base disturbances	Extreme acidosis or alkalosis impairs neuronal function

Management: Correct all metabolic disturbances to near-normal before proceeding. The examination is only valid in metabolically stable patients.

- Bradley and Daroff's Neurology in Clinical Practice; Miller's Anesthesia, 10e

5. Endocrine Emergencies

Myxedema coma (severe hypothyroidism): Profound CNS depression, hypothermia, apnea
Addisonian crisis / severe adrenal insufficiency: Can cause profound coma

These are uncommon but recognized reversible causes of apparent brain death.

6. Severe Hemodynamic Instability

Why it matters: The brain death examination requires a systolic BP ≥ 100 mmHg (many protocols). Profound hypotension can itself cause cerebral hypoperfusion and suppress neurological function. Additionally:

The apnea test requires hemodynamic stability to be safely performed
Circulatory failure confounds interpretation - the absent brainstem function may be a consequence of hypoperfusion rather than irreversible structural death

- Bradley and Daroff's Neurology in Clinical Practice

7. Peripheral Nervous System Disorders

Conditions causing motor and respiratory paralysis at the peripheral level rather than the brain:

Condition	Mechanism
Guillain-Barré syndrome	Peripheral demyelination → areflexia, respiratory failure, cranial nerve palsies
Critical illness polyneuropathy / myopathy	ICU-acquired neuromuscular failure
High cervical cord injury	Quadriplegia + apnea; brainstem may be intact
Botulism	Presynaptic NMJ blockade → areflexia, apnea, ophthalmoplegia

These are particularly dangerous because they can abolish all motor responses and cause apnea while brainstem function is completely intact. In these conditions, an ancillary blood flow study (confirming intact cerebral perfusion) is the safest way to avoid a misdiagnosis.

- Adams and Victor's Principles of Neurology

8. Structural Mimics (Disorders of Consciousness)

These are not metabolic confounders but clinical mimics that must be distinguished:

Locked-In Syndrome

Caused by a ventral pontine lesion (infarct, hemorrhage, tumor, central pontine myelinolysis)
Patient has intact consciousness and cognition but complete motor paralysis (bilateral corticospinal and corticobulbar tract destruction)
Communication possible only via vertical eye movements or blinking
Brainstem is NOT dead - the patient is awake and aware
Direct clue: preserved vertical eye movements or blinking in response to commands

Vegetative State / Unresponsive Wakefulness Syndrome

Arousal (sleep-wake cycles) preserved; awareness absent
Brainstem reflexes and spontaneous breathing intact
Not brain death

Severe Hypothermic Cardiac Arrest

Documented cases of complete neurological recovery after apparent brain death during deep hypothermic cardiac arrest

- Goldman-Cecil Medicine; Plum and Posner's Diagnosis and Treatment of Stupor and Coma

Timing: When Is It Safe to Examine?

A waiting period is built into all guidelines precisely because of these confounders:

General rule: Several hours must pass after onset of brain injury before the examination is performed
If cardiac arrest was the antecedent event OR if drug/alcohol intoxication could plausibly have contributed: wait approximately 24 hours before testing and pronouncing death, AND perform toxicologic serum/urine screening
If the cause is clear (massive cerebral hemorrhage, severe TBI with overwhelming imaging evidence): ~6 hours may be adequate in adults
Never declare brain death within hours of ED arrival or transfer from another facility - history is too incomplete

- Adams and Victor's Principles of Neurology

The Isoelectric EEG Caveat

A flat EEG alone does not equal brain death when confounders are present. Reversible electrocerebral silence occurs with:

Profound drug intoxication (especially barbiturates)
Severe hypothermia
Immediately post-cardiac arrest

This is why EEG, even when used as an ancillary test, must always be interpreted within the clinical context of confirmed confounder exclusion.

- Adams and Victor's Principles of Neurology

Summary Table

Confounder	Mechanism	Key Action to Exclude
Hypothermia	CNS depression, reversible	Core temp ≥ 36°C
CNS depressants (barbiturates, BZDs, opioids)	Suppress brainstem reflexes + apnea	5 half-lives clearance; tox screen
Neuromuscular blockers	Paralyze motor exam + apnea	Train-of-four stimulation shows no block
Metabolic derangements (electrolytes, glucose, acid-base)	Encephalopathy	Correct to near-normal
Hepatic/renal failure	Encephalopathy + prolonged drug half-lives	Treat; extend waiting period
Hemodynamic instability	Cerebral hypoperfusion	SBP ≥ 100 mmHg
GBS / peripheral NMJ disorders	Peripheral apnea + areflexia	Ancillary CBF study
Locked-in syndrome	Clinical mimic - conscious patient	Look for preserved vertical gaze
Endocrine emergencies (myxedema)	CNS depression	TSH, cortisol; treat first

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