Evaluation of cerebral hemodynamics in a head-injured patient with hypovolemia using transcranial Doppler sonography.

A 20-year-old man presented with hypovolemic shock caused by abdominal injury. Cerebral hemodynamics were evaluated by transcranial Doppler (TCD) sonography. Middle cerebral artery flow velocities decreased, and the pulsatility indices increased markedly. Particularly, the waveform of the left middle cerebral artery showed a systolic peak, suggesting an increased intracranial pressure. Actual intracranial pressure was 7 mm Hg, and the cerebral perfusion pressure (CPP) was 51 mm Hg. These abnormal Doppler signals seemed to be caused by a compromise in CPP and to be aggravated by hypovolemia. The patient was discharged with a residual mild memory disturbance. Hypovolemia aggravates a reduced cerebral blood flow caused by a compromised CPP, and the waveform of TCD in a case of hypovolemic shock should be differentiated from intracranial hypertension.