Transcranial doppler (TCD) ultrasonography is routinely used to evaluate the direction and velocity of blood in major intracranial vessels. This allows for identification of focal stenosis, increased resistance, or adequacy of blood flow, prompting some to use it as a confirmatory test for brain death. The TCD waveforms of the middle cerebral artery seen in cerebral circulatory arrest include oscillating, short systolic spikes, or absent signals. This noninvasive modality may be useful as an adjunct in brain death determination when circumstances prevent comprehensive clinical examination. However, its utility may be limited, as in a recent study, results of TCD were inconclusive in 43% of brain dead patients.
Christopher R. Newey, DO, MS, Cleveland Clinic
Disclosure: Dr. Newey has no financial disclosures to report.
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