Cerebral blood flow velocity alterations during obstructive sleep apnea syndrome.

We recorded cerebral blood flow velocity (CBFV) for the assessment of CO2-regulated alterations during apnea by means of transcranial Doppler ultrasound in a patient with obstructive sleep apnea syndrome. CBFV increased up to doubled peak flow values during obstructive apneic phases. The results provide evidence for a normal CO2 regulation of CBFV leading to periodic vascular stress during the night.