The author performed transcranial doppler study to measure the CO2 reactivity to the entire basal cerebral arteries in 30 cases of control group and 10 cases of disease group between 3rd and 7th day after insult. The control persons involved 10 cases of 3rd decade, 10 cases of 5th, 10 cases of 7th, and the diasease persons involved 10 cases of spotanenous subarachnoid hemorrhages. All disease patients were examined by single photon emission computed tomography and their results were compared to Doppler CO2 reactivities.

In control group, the mean blood flow velocity and pulsatility index increased with age, but the CO2 reactivity decreased. In patient group, MBFV, PI index, MI ratio were not correlated to the presence of disease, but only CO2 index was decreased than the same age group of normal control. The regions showing abnormal ROI by SPECT well corresponded with the regions showing decreased CO2 reactivity. There was no close correlation between ROI(Region of Interest) index and CO2 index, but the CO2 reactivity was remarkably decreased in the region which showed abnormal regional cerebral blood flow in SPECT findings(p=0.04). In the relationship between the various prognostic factors, ROI increased as the clinical status worse(r=-0.05, p=0.0008), the acute prognosis(3Mo) had positive correlation with CO2 omdex(r=0.32, p=0.04) or clinical status, and negative correlation with ROI index(r=0.40, p=0.0094).

Transcranial doppler CO2 testing in patients with spotanenous subarachnoid hemorrhage provides useful information regarding hemodynamic state, prognosis and determination of beneficial effects specific therapy. In the various TCD parameters, CO2 index was correlated well with the acute prognosis.