A Novel Sphygmography Based on Vascular Geometry and Arterial Model

Previous research on the non-invasive measurement of radial pulse waveform had no standardized quantitative and qualitative procedures. The aim of this study was to propose a new non-invasive measuring apparatus that had a three-axis sphygmography and a standard positioning procedure for detecting the optimal measure site and measuring an accurate pulse waveform. The artery vessel can be viewed as a cylinder, so, during measurement, if the sensor was not placed right at the centre but at an angle, the measured waveform would be distorted. Also, the blood vessel is made of elastic material. Its compliance changes with transmural pressure. When transmural pressure is equal to zero, compliance is at its maximum. The strain gauge and pizeoresistor was used to measure the radial arterial diameter change and pulse waveform, respectively.