P10.07 A Ppg Measurement Setup and Pulse Wave Analysis for Arterial Stiffness

Abstract

The light energy absorption of whole blood in the visible and infrared range is partly caused by the oxidized and reduced haemoglobin. The measurement principle can be applied for photoplethysmography (PPG). Our PPG measures the blood flux in human vessels with means of red and infrared light absorption. The absorption of light varies with the oxygen concentration and amount of blood in vessels. The PPG device has phase sensitive detection electronics which proved to be a good solution for the measurement of small absorption signals simultaneously at two different wavelengths, 660 and 940 nm. In practice, the PPG waveforms, called pulse waves, can be rapidly and simply acquired by a PIN photodiode which measures the transmission of red and infra-red LED light through the forefinger and the second toe simultaneously. The waveforms are characteristics for the young person but different for the elderly person. The four template waveforms are in the consideration for waveform analysis and we get the accurate results enough. The PPG amplitude can increase and decrease caused by the autonomic fluctuation. In the wave analysis,the first wave is called a percussion wave, the second is called tidal wave, and the third is a dicrotic. The PPG measurements may provide cheap, simple and accurate methods of diagnosing arterial and, especially vascular diseases. Moreover, further development of the theoretical model that correlates the waveform of the detected finger tip wave caused by heartbeat oscillations and the hemodynamic parameters could improve the accuracy of the method and potentially lead to a better quantification of the measured parameters used for arterial stiffness.