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Estimation of Brain Death Using Transcranial Doppler Sonography

Flow patterns of the velocity measured by transcranial Doppler (TCD) were compared with the changes of intracranial pressure (ICP) in patient with subarachnoid hemorrhage and severe head trauma in our department. The flow velocities in the middle cerebral artery or internal carotid atrery were measured using TCD in 12 patients who developed brain death due to progressive increased ICP. Our studies demonstrated that flow patterns were influenced in response to increased ICP. The flow pattern showed a low resistance high flow profile in physiological state. On the other hand, TCD demonstrated a high resistance low flow in reply to increase in ICP.In the stage of marked increase in ICP, TCD revealed progressive reduction of mean flow velocity and diastric negative flow. Finally an oscillating flow pattern or spiky systolic flow pattern was estimated by TCD in brain death patients. TCD is beneficial to evaluate the arrest of intracranial circulation in brain death.