V.B. Parashin, M.N. Simonenko, E.G. Chernomorsky

Elastic compliance of arterial wall is a one of the most important mechanical characteristics of blood a vessel. It defines the main hemodynamic parameters of peripheral blood circulation process. Elastic characteristic dependence of pressure on volume mostly specifies input impedance to cardiac output and the state of violent oscillations of blood flow and pressure. For an artery site under occlusion during the change of arterial blood pressure plays a leading role in forming of criteria for balance of external pressure and the pressure in arterial vessel corresponding to minimal dynamic, average and final systolic levels. Research of elastic characteristics of arteries has been carried out for four centuries already but only recently due to development of medical measurement systems and information technology it became possible to estimate these vital parameters in vivo for concrete patient. Measuring arterial blood pressure by means of occlusive oscillometric method here comes the possibility to plot the volume compliance curve according signal oscillogram. The proposed method consists of several stages. First of all selecting of informative fragment of source signal should be carried out as well as low-frequency filtering elucidated by the presence of processes connected with air draining out of the cuff. The next step includes envelop forming and its subtraction from the main signal sequence. As a result, an oscillogram appears, fixed by minimums corresponding to ordinate axis. Afterwards abscises axis is changed in the way that time samples are substituted by transmural pressure values. The final step consists of differential volume compliance curve plotting and its valuation on the value of volume change in zero point of transmural pressure respectively. Evaluation is performed not to take pulse pressure fluctuations into consideration. Applying proposed methodology a series of experiments was carried out revealing strong dependence between parameters of volume compliance curve and age of patients. Significant periodicity of experimental results for chosen examinees was observed. Analysis of width values of volume compliance curve at the levels of 0.90, 0.75 and 0.50. For a group of healthy examinees averaged volume compliance characteristic was plotted. Standard deviations and confidence intervals were calculated. From the experimental results it can be noticed that proposed method of volume compliance estimation of human arteries quantitatively shows significant differences in arteries elasticity for various group of patients. It is supposed to be reproducible and accurate enough to be considered as a reliable attribute for arteries volume compliance estimation. Utilization of noninvasive methods for peripheral arteries elastic characteristic measurements develops possibilities of existing devices for blood pressure evaluation and gives an opportunity to perform complex estimation of arterial blood circulation for early stage diagnostics of cardiovascular diseases.

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