Intracranial flow patterns at increasing intracranial pressure.

In the course of a pilot study, changes in intracranial pressure were compared with the transcranial Doppler findings of the middle cerebral artery. The cases of five patients were discussed who developed dissociated brain death in spite of intensive therapeutic measures. The studies showed that changes of the intracranial pressure influenced the flow patterns considerably: at increasing intracranial pressure (decreasing cerebral perfusion pressure) a progressive reduction of the systolic and above all diastolic flow velocities and finally a pendular flow occurred. These changes could be recorded quantitatively by means of the "Pourcelot index" and the mean flow velocity. Acute changes of the intracranial pressure can be detected at an early stage by noninvasive transcranial Doppler studies and can be followed by adequate intensive therapy.