A Study On The Noninvasive Measurement Of The Distensibility Of Artery:the Method Of Wave Intensity

Distensibility is an important index to estimate the cardiovascular system. Traditionally, the noninvasive method was used to estimate the aortic distensibility in the longitudinal direction with the average velocity of the wave. The distensibility of the surface was also determined by the arterial pulse pressure. The research hotspot in this field is that developing a more accurate method to determine the noninvasive distensibility of artery.This study developed a method to noninvasively determine the distensibility of artery based on the theory of the wave intensity analysis. The main contents of this work are as follows.1. Theoretical analysis:We systematically deduced the whole theory based on the theory of wave intensity analysis. This study included PU-loop method, wave intensity, lnDU-loop method, noninvasive wave intensity, and the separation of wave using noninvasive wave intensity method. This paper described the wave intensity system clearly and precisely. According to the data handling and data transmission, this method was optimal designed by the Matlab. The designed program was used by the following experiment and it also useful on clinic.2. Experiment test:Two same latex tubes were selected in this paper, one of the tubes was added with sleeves to simulate the human hardening artery. Sine wave pump were used to simulate heart, water were used to simulate blood and pool to simulate human internal conditions. After connecting equipment, arterial pressure, flow velocity and the diameter of the different location were measure. Non-invasive measurement analysis method were used to measure the tube distensibility and compared with the other two common methods. Results showed that this method is a simple, easy and noninvasive measurement method of artery distensibility. This method can be used to measure artery distensibility effectively. This method can obtain more information about the arterial wall (reflection wave arrived time, strength of transient wave), compared with common directly measurement method of artery expansionary. The method can avoid pressure measurement, measure diameter and flow velocity through non-invasive way, relative to traditional strong instantaneous wave analysis. In conclusion, non-invasive measurement can be recommended in the practical application.In conclusion, this non-invasive method can measure the artery distensibility effectively in some areas, and this method should be avoid to be used at blood bifurcated point of vascular system in actual measurement system.