Clinical application of tcd in patients with vertigo co2 reactivity

Abstract

The response of cerebral blood flow to changes in the carbon dioxide partial pressue (i.e., CO2 reactivity) has been evaluated as a parameter of cerebral perfusion reserve in patients with vertigo by transcranial Doppler ultrasonography (TCD). We have examined the mean blood flow velocity (FV), and CO2 reactivity of basilar artery (BA) by TCD. Nine patients with cerebral infarction, 46 patients with vertebrobasilar insufficiency (VBI) (17 vascular VBI and 29 hemodynamic VBI), 29 patients with peripheral vertigo, 46 patients with vertigo of unknown origin and 14 normal subjects were enrolled in this study. CO2 reactivity in patients with cerebral infarction and vascular VBI was significantly lower than that in normal subjects. These findings demonstrate that CO2 reactivity measured by TCD evaluates the insufficiency of cerebral circulation in vertigo patients.