A number of methods for evaluating cerebrovascular reserves have been used in patients with atherosclerotic affections of the cervical or cerebral arteries to assess the integrity of intracranial hemodynamics. A cerebrovascular reserve may be evaluated by means of CO2-reactivity. At present, no standard and generally accepted method of measuring the CO2-reactivity index has been applied so far. The study aimed at finding out the reproducibility of our methods of measurements using transcranial dopplerometry (TCD). Two measurements of CO2-reactivity index were carried out in a set of 20 volunteers during one session. The reproducibility of measuring velocity using TCD was excellent (the mean difference 1.6–1.9 cm/s, variability coefficient 16.7–17.9 %, correlation coefficient 0.99, and percentage of the average error 2.8–3.3). The reproducibility of measuring CO2-reactivity index was a little lower (the mean difference of CO2-reactivity index 2.7–3.4 %/kPa, variability coefficient 13.6–21.3 %, correlation coefficient 0.73–0.89, percentage of error 9.8–12.2 %). The reproducibility of measuring CO2-reactivity index by means of our methods was comparable with other modifications of measuring CO2-reactivity index.

        Key words: cerebral arterial reserve, cerebrovascular reactivity, autoregulation, cerebral blood flow, ultrasonography, transcranial dopplerometry, reproducibility