VIBRATION PLETHYSMOGRAPHIC METHOD OF ARTERIAL COMPLIANCE ANALYSIS IN DEPENDENCE ON TRANSMURAL PRESSURE
| Authors | |
|---|---|
| Year of publication | 2014 |
| Type | Conference abstract |
| Citation | |
| Description | The aim of this study was to obtain detailed analysis of relationship between a finger arterial compliance C [ml/mmHg] and an arterial transmural pressure Pt [mmHg]. We constructed a dynamic plethysmograph enabling to setup constant pressure Pcss [mmHg] and superimposed fast pressure vibration in the finger cuff (equipped by source of infra-red light and photo-electric sensor for measurement of arterial volume). Pcss could be set on required time interval in steps in range of 0 to 200 mmHg, and on sinusoidal pressure oscillation with amplitude Pca (2 mmHg) and frequency f (0 – 40 Hz in increments 5 Hz). At the same time continuous blood pressure Pb was measured on adjacent finger (Portapres). We described volume dependency of an unitary arterial length on a time-varying transmural pressure acting on arterial wall (externally Pcss+Pca.sin(w), internally Pb) by second order differential equation for volume. This equation was linearized in small range of selected Pb. In the next step, Fourier transform was applied to obtain frequency characteristic in analytic form of complex linear combination of frequency functions. While series of oscillations [Pca, f] were applied for each Pcss, corresponding response of plethysmogram was measured. Amplitude spectra were obtained to estimate coefficients of frequency characteristic by regression analysis. We determined absolute value: elastance E, and its inverse value: compliance (C=1/E). Than C=C(Pt) was acquired by applying sequences of oscillations for different Pcss (and thus Pt) by the above described procedure. This methodology will be used for study of finger arterial compliance on different physiological and pathological conditions. |
| Related projects: |