**4. Statistical methods**

Due to the abnormality of the value distribution of oscillation power of haemodynamic indicators, their medians, the limits of 25 and 75 percentile were found; the average values and their errors for AP indicators distributed normally were determined. The reliability of differences between values in different OMC phases was estimated by means of Wilcoxon paired comparison and Student's t-test. The relationship between indicators was calculated by the nonparametric Spearman correlation coefficient.
