Is a repeat electroencephalogram (EEG) necessary after 48 hours to confirm brain death diagnosis?

From the Guidelines

Brain death has not been confirmed based on the EEG report, and a repeat EEG after 48 hours is recommended to monitor for any changes in brain activity. The presence of reactive waves in all leads indicates ongoing brain activity, which is inconsistent with brain death, as brain death is characterized by the absence of electrical activity (isoelectric or flat EEG) 1. During this waiting period, continue all necessary supportive care for the patient. The presence of artifacts in the recording is common but doesn't invalidate the finding of reactive waves.

Key Considerations

• Brain death determination typically requires multiple clinical criteria beyond just EEG findings, including absence of brainstem reflexes and apnea testing, so a comprehensive neurological examination should be performed alongside the repeat EEG 1.
• The 48-hour waiting period allows time to rule out confounding factors like sedative medications or metabolic disturbances that might temporarily affect brain activity, and it is essential to ensure that the patient's condition is stable and that any potential reversible causes of coma have been addressed 1.
• According to the guidelines for the determination of brain death in infants and children, a waiting period of 24 hours is recommended before further ancillary testing, using a radionuclide CBF study, is performed, allowing adequate clearance of Tc-99m 1.
• The patient should continue to be observed and medically treated until brain death can be declared solely on clinical examination criteria and apnea testing based on recommended observation periods, or a follow-up ancillary study can be performed to assist and is consistent with the determination of brain death 1.

Recommendations

• Continue all necessary supportive care for the patient during the waiting period.
• Perform a comprehensive neurological examination alongside the repeat EEG.
• Ensure that the patient's condition is stable and that any potential reversible causes of coma have been addressed before declaring brain death.
• Follow the guidelines for the determination of brain death in infants and children, including the recommended waiting periods and observation periods 1.

From the Research

EEG Report Analysis

• The EEG report shows reactive waves in all leads with artifacts recorded, which may indicate some level of brain activity.
• The report recommends repeating the EEG after 48 hours, suggesting that the current results are not conclusive for brain death diagnosis.

Brain Death Diagnosis

• According to 2, brain death is diagnosed based on clinical grounds and neurologic examination, with ancillary tests such as EEG used to confirm the diagnosis.
• The American Academy of Neurology (AAN) recommends EEG as an ancillary test to confirm brain death, but notes that it is not always reliable 3.
• Studies have shown that EEG activity can be present in patients who are clinically diagnosed as brain dead, with some patients showing low-voltage theta or beta activity, sleep-like activity, or alpha-like activity 3.

EEG in Brain Death Diagnosis

• The use of EEG as a confirmatory test for brain death is questionable, as it may not always accurately reflect the absence of brain activity 3.
• In Japan, EEG is mandatory for brain death diagnosis, even in cases where apnea testing is used 4.
• The American Clinical Neurophysiology Society has guidelines for EEG reporting, which include standardized formats for reporting EEG results and recommendations for technical conditions and clinical correlation 5.

Apnea Testing

• Apnea testing is one of the three cardinal findings in brain death, and is used to determine the absence of spontaneous breathing 6.
• The test must be performed using positive end-expiratory pressure, and there are various modifications and monitoring techniques used to ensure safety and accuracy 6.