The Effect of Chunghyul-Dan on Hyperventilation-Induced Carbon Dioxide Reactivity of the Middle Cerebral Artery in Normal Subjects: A Dose-Dependent Study

Abstract

Background. This study was conducted to show the prompt effect of chunghyul-dan (CHD) on cerebral hemodynamics in order to provide evidence for its use in stroke prevention. Methods. Hyperventilation-induced CO₂ reactivity of the middle cerebral artery was measured in 12 healthy male volunteers (mean age: 26.3 ± 1.1 years) using transcranial Doppler sonography. All subjects were examined before and for 3 hours after administration, with an interval of 1 week between measurements. Results. Compared to baseline, the CO₂ reactivity of the middle cerebral artery increased significantly at 2 and 3 hours after the administration of CHD (600 mg and 1200 mg). The mean blood pressure and heart rate did not vary from the baseline values in all groups. Conclusion. These data suggest that CHD administration (especially 600 mg) immediately improves cerebral blood flow.

Figure 1

Study design timeline. Measurements were repeated four times, at least 1 week apart, according to the multiple-crossover design. CHD, chunghyul-dan; hr, hour; HR, heart rate; BP, blood pressure; TCD, transcranial Doppler sonography; hypervent., hyperventilation.

Figure 2

Percent changes in CO₂ reactivity (%) before and after CHD administration. The lines represent the means ± SEM. CHD, chunghyul-dan; hr, hour. ^#p < 0.05 versus control at the same time points by Bonferroni multiple comparisons after one-way repeated measures analysis of variation (RM ANOVA). ^∗p < 0.05 versus CHD 300 mg at the same time points by Bonferroni multiple comparisons after one-way RM ANOVA.

Figure 3

Percent changes in CV40 (%) before and after CHD administration. Values are means ± SEM. CHD, chunghyul-dan; hr, hour. ^#p < 0.05 versus control at the same time points by Bonferroni multiple comparisons after one-way repeated measures analysis of variation (RM ANOVA). ^∗p < 0.05 versus CHD 300 mg at the same time points by Bonferroni multiple comparisons after one-way RM ANOVA.

Figure 4

Pearson's correlation analysis of the changes in CO₂ reactivity and CV40 before and after CHD administration. A significant correlation is shown between CHD administration-mediated changes in CO₂ reactivity and the CV40 of the MCA (p < 0.001, r = 0.621).