Coefficients of variation were calculated for pulse rate (CV-PR) and blood pressure (CV-BP) under various respiratory conditions using a non-invasive method (the Finapres method), and the respiratory resonant phenomenon between pulse-rate variability and blood-pressure fluctuation was investigated. Subjects of this study included 148 healthy adults, 75 patients with diabetes mellitus (DM) and 64 patients with vibration syndrome (VS).
During deep breathing of healthy adults in the sitting position, CV-PR was closely correlated with the coefficient of variation for diastolic blood pressure (CV-dBP) (R=0.75, p<0.01). Although CV-PR has been used as an index of autonomic nervous functions, it is strongly influenced by blood pressure and respiratory depth, so CV-PR itself is not suitable for investigating the present phenomena and seems to require correction.
The corrected value (as obtained by dividing CV-PR by CV-dBP) in healthy adults during deep breathing in the sitting position was 1.05±0.21, extremely close to 1.0. This value decreased significantly with age (p<0.01) and was significantly lower (0.59+0.29) in the patients with DM than in healthy control adults (p<0.001). The value for the patients with VS was not significantly lower than that in the normal control adults. In the patients with VS and positive Raynaud's phenomenon, a significant decrease in value with age was noted (p<0.01), whereas the patients with VS and negative Raynaud's phenomenon showed no change in value with age.
The coefficients of variation for pulse rate and blood pressure with their corrected values seemed to be useful as general indices of the sensitivity of several cardiovascular vagal reflexes including the baroreceptor reflex, which is probably involved in the present phenomenon. In addition, an examination of this phenomenon was found to be useful for determining the degree of complications in patients with DM and for assessing the peripheral circulatory function and therapeutic effects of balneotherapy on patients with VS.