Cardiovascular Primary Parameter Analysis Based On Radial Pulse Wave

Cardiovascular diseases are the killer treated to human health all the time. It is a major problem that needed to be solved for the world to diagnose or predict cardiovascular diseases effectively. A large number of clinical results have confirmed that pulse wave is extremely rich in physiological and pathological information, from which we can acquire parameters reflect the performance of cardiovascular system. However, noises will be introduced during the acquisition of pulse wave signal inevitably, which can influence the accuracy of cardiovascular parameters calculation. In this thesis, two parts are studied:the processing of pulse wave and the calculation of cardiovascular parameters.In this thesis, we firstly proposed an adaptive denoising method based on Empirical Mode Decomposition (EMD), combining with wavelet threshold method and the characteristics of noise distribution in pulse signal. The method proposed is obviously superior to wavelet threshold denoising method. In the same way, baseline drift in pulse wave was removed effectively. Then several characteristics points used to calculate cardiovascular parameters were extracted based on the threshold method. Finally, this thesis analyzed the influence factors of pulse wave:contact pressure, tilting degrees and time duration.This thesis calculated cardiovascular parameters (cardiac output, peripheral resistance etc.) based on K value method, and also compared those parameters with measured parameters. They were almost the same under the normal pulse pressure, but they had a big difference under the larger pulse pressure. So a Correction Coefficient (CC) was proposed and analyzed relevance with a series of parameters. And we obtained revised formula of Cardiac Output (CO) through multiple linear regression analysis. The revised CO and the CO before being revised compared the measured parameter (4.0167±0.6565L/min vs.4.0093±0.6967L/min and7.1364±3.4862L/min, the significant difference p1<0.05, p2>0.05respectively). The results showed that the revised CO is more close to the measured CO, and they had no significant difference. In order to test the validity of this method, we compared the revised CO with the CO measured by the heat dilution method. The relative error was till within5%. Finally we calculated other cardiovascular parameters via revised CO. The results showed that the revised parameters was more close to measured parameters, so they can be used to assist clinicians to estimate patients’cardiovascular status or patients to estimate their own cardiovascular status.