What are the guidelines for determining brain death (cerebral death)?

From the Guidelines

Brain death in infants and children is diagnosed through a systematic clinical examination that confirms three key findings: coma with complete unresponsiveness, absence of all brainstem reflexes, and apnea, as outlined in the 2011 guidelines by the American Academy of Pediatrics 1.

Key Findings

• Coma with complete unresponsiveness
• Absence of all brainstem reflexes
• Apnea (inability to breathe independently)

Prerequisites for Examination

• Ruling out confounding factors like severe hypothermia (temperature should be >36°C) 1
• Significant hypotension (systolic BP >100 mmHg) 1
• Metabolic or endocrine disturbances
• Presence of CNS-depressant medications

Clinical Examination

• Testing for absence of pupillary light reflexes, corneal reflexes, oculocephalic and oculovestibular reflexes, gag and cough reflexes, and motor responses to painful stimuli 1
• Apnea test performed by disconnecting the patient from the ventilator while providing oxygen, then observing for respiratory effort while PaCO2 rises above 60 mmHg 1

Observation Periods

• Two separate examinations separated by an observation period (typically 24 hours for neonates and 12 hours for infants and children) 1

Confirmatory Tests

• Electroencephalography, cerebral angiography, transcranial Doppler, or nuclear medicine perfusion studies may be used if clinical examination is inconclusive or cannot be fully performed 1

Declaration of Death

• Death is declared after confirmation and completion of the second clinical examination and apnea test 1

From the Research

Brain Death Guidelines

• The diagnosis of brain death (BD) is made on clinical grounds and neurologic examination, with the American Academy of Neurology (AAN) emphasizing three specific clinical findings: coma, absence of brainstem reflexes, and apnea 2.
• Ancillary tests are needed when neurologic examination or apnea test cannot be performed, with AAN-recommended tests including electroencephalogram, catheter cerebral angiogram, transcranial Doppler, and nuclear scintigraphy 2.
• Digital subtraction angiography is considered the gold standard for confirmation of lack of cerebral blood flow, while computed tomography angiogram (CTA) and magnetic resonance angiogram are not currently recommended by AAN but may be useful in the future 2, 3.

Clinical Criteria for Brain Death

• The clinical diagnosis of brain death is determined by a comprehensive clinical examination that involves at least 25 individual assessments, excluding confounding factors, examining the patient carefully, and performing an apnea test 4.
• The apnea test is a mandatory examination for determining brain death, but it may be associated with potential complications such as severe hypotension, pneumothorax, and cardiac arrhythmia 5.
• Alternative ancillary tests, such as CTA, may be used to confirm brain death when the apnea test is terminated or impossible to perform 3, 5.

Ancillary Tests for Brain Death

• CTA has been shown to have a sensitivity of 75%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 33% in diagnosing brain death 3.
• Nuclear scintigraphy, such as 99mTechnetium hexa methyl propylene amine oxime, can confirm brain death by showing lack of intracranial radiotracer uptake 2.
• Transcranial Doppler can indicate cerebral circulatory arrest by showing flow patterns without forward flow progress 2.

Special Considerations

• Brain death determination in pediatric populations requires special consideration, with existing controversies and future directions in the field 6.
• Extracorporeal membrane oxygenation and target temperature management may affect brain death determination, and special discussion is needed for these cases 6.
• Common mimics of brain death, such as hypothermia, locked-in syndrome, and drug intoxication, must be ruled out before confirming brain death 2.