What is the proper assessment and management protocol for a patient suspected of being brain dead?

Brain Death Assessment Protocol

Brain death determination requires two complete neurological examinations with apnea testing, performed by different attending physicians and separated by an observation period, after establishing an irreversible cause and excluding all confounding factors. 1, 2

Prerequisites Before Assessment

Correct all confounding factors before initiating brain death evaluation:

• Normalize hemodynamics: Treat hypotension to ensure adequate cerebral perfusion pressure 1, 2
• Correct core temperature: Hypothermia must be reversed as it can mimic brain death 1, 2
• Resolve metabolic disturbances: Address electrolyte abnormalities, acid-base disorders, and endocrine dysfunction that could affect neurologic examination 1, 2
• Clear sedating medications: Discontinue sedatives, analgesics, neuromuscular blockers, and anticonvulsants for adequate time based on elimination half-lives 1, 2
• Verify medication levels: Obtain blood levels to confirm sedative agents are in low to mid-therapeutic range, not supratherapeutic 1
• Defer assessment after resuscitation: Wait 24-48 hours following cardiopulmonary resuscitation or severe acute brain injury if concerns exist about examination reliability 1

Critical caveat: If supratherapeutic or high therapeutic levels of sedatives are present, brain death diagnosis based on clinical examination alone cannot be made—proceed to ancillary testing instead 1

Clinical Neurological Examination

The examination must document complete absence of all brain and brainstem function: 1, 2

Coma Assessment

• Complete loss of consciousness, vocalization, and volitional activity 1
• No eye opening or eye movement to noxious stimuli 1
• No motor response to noxious stimuli except spinally-mediated reflexes (requires expertise to differentiate) 1

Brainstem Reflex Testing

• Pupillary reflex: Pupils midposition or fully dilated (4-9 mm), no response to bright light in both eyes (use magnifying glass if uncertain) 1
• Corneal reflex: No eyelid movement when cornea touched with tissue, cotton swab, or water squirts 1
• Facial movement: No grimacing with deep pressure on temporomandibular joint condyles or supraorbital ridge 1
• Oculovestibular reflex (caloric testing): Elevate head 30 degrees, confirm patent external auditory canal, irrigate each ear separately with 10-50 mL ice water—no eye movement should occur 1
• Pharyngeal/gag reflex: No response to posterior pharynx stimulation with tongue blade or suction 1
• Tracheal/cough reflex: No cough response when suction catheter advanced to carina with 1-2 suctioning passes 1
• Absent rooting and sucking reflexes 1

Apnea Testing Protocol

Apnea testing confirms absence of respiratory drive and is mandatory for brain death diagnosis: 1, 2

Procedure

• Pre-oxygenate with 100% oxygen for 5-10 minutes 2
• Disconnect from ventilator while providing oxygen via tracheal catheter or T-piece 2
• Monitor continuously for any respiratory effort 2
• Allow PaCO₂ to rise to ≥60 mmHg OR ≥20 mmHg above baseline 1, 2

Positive test (confirms brain death): No respiratory effort despite adequate CO₂ stimulus 1

Special consideration: Patients with chronic respiratory disease may require PaCO₂ ≥20 mmHg above their baseline level 1

Abort Testing If:

• Hemodynamic instability occurs 1
• Oxygen saturation drops to ≤85% 1
• Unable to reach target PaCO₂ 1

If apnea test cannot be completed safely, proceed immediately to ancillary studies 1

Observation Periods and Repeat Examination

Two examinations by different attending physicians are required: 1

• Neonates (37 weeks gestation to 30 days): 24-hour observation period between examinations 1
• Infants and children (>30 days to 18 years): 12-hour observation period 1
• Adults: Guidelines allow shorter intervals, though specific timing varies by institution 3

The first examination establishes criteria are met; the second examination confirms the irreversible condition 1

Ancillary Testing

Ancillary studies are NOT required for brain death determination if clinical examination and apnea testing can be completed 1, 2

Indications for Ancillary Testing:

• Components of examination or apnea testing cannot be completed safely 1, 2
• Uncertainty about neurologic examination results 1, 2
• Medication effects may interfere with evaluation 1, 2
• To reduce observation period between examinations 1

Accepted Ancillary Tests:

• Electroencephalogram (EEG) showing electrocerebral silence 1, 2
• Cerebral blood flow studies: Four-vessel angiography, radionuclide cerebral blood flow study, or CT angiography 2, 4

Important limitation: Ancillary studies are NOT a substitute for neurologic examination—they only supplement when examination cannot be completed 1

If ancillary study is equivocal or validity is questioned, the patient cannot be pronounced dead—continue observation for 24 hours before repeat testing 1

Declaration of Death

Death is declared only after: 1

• Completion of second clinical examination by different attending physician 1
• Successful apnea testing with both examinations 1
• All examination components remain consistent with brain death 1
• When ancillary studies used, documentation that completable examination components remain consistent with brain death 1

Documentation Requirements

Comprehensive documentation must include: 2

• Known irreversible cause of coma established 2
• All confounding factors addressed and corrected 2
• Detailed findings of both neurological examinations 2
• Complete apnea testing results with specific PaCO₂ values 2
• When ancillary tests used, specific findings consistent with brain death 2

Examinations should be performed by experienced clinicians with specific training in neurocritical care 1

Common Pitfalls to Avoid

Premature assessment: Never begin evaluation until all prerequisites are met and adequate time has passed after resuscitation or medication administration 1, 5

Incomplete examination: All brainstem reflexes must be tested systematically—missing even one component invalidates the assessment 5

Inadequate apnea testing: Failure to reach target PaCO₂ or aborting test prematurely requires ancillary testing rather than clinical diagnosis alone 1, 5

Misinterpreting spinal reflexes: Spinal-mediated movements can occur in brain death and should not be confused with retained brain function—requires clinical expertise 1, 5