Hee-Jung Kang

Cuffless and Noninvasive Tonometry Mean Arterial Pressure Measurement by Physiological Characteristics and Applied Pressure

We developed a cuffless and noninvasive measurement technique of blood pressure using tonometric pressure sensor. With observation that the maximum value of a pulse pressure is not obtained at mean arterial pressure (MAP), we have figured out MAP based on the physiological characteristic including the elasticity of wrist tissue, the depth of blood vessel. Through an analysis of 198 clinic data, we have induced the regression equation of the MAP. The probability of the elasticity, depth and APM to explain MAP was 92.1%. The mean difference and the standard deviation between the MAP predicted from the regression equation and the MAP measured by commercial cuff type BP meter were Z-3.183 mmHg and 5.133 mmHg respectively. Comparing the results with the American national standard for electronic or automated sphygmomanometers, we can conclude that the results are quite reliable and promising. Detecting only one part of the body and using only one device are quite advantageous over other BP measurement technique. Our technique makes new way for the cuffless BP measurement

Radial Pulse Type Changed by the Applied Pressure in Same Position

It has been shown that the systolic augmentation index (AI) in the central arteries, including the aorta and carotid arteries, changes with age. The AI can also be obtained from the peripheral arteries. And recently some investigations prove that simple and easily-obtainable radial AI is also age-dependent and could be a useful index of vascular aging. A new method to measure pulse waveform by multi-step pressure applied on radial artery was developed by DAEYOMEDI Co., Ltd. This system borrowed a robot arm for applying precision pressure to take pulses stably and to find out a representative pulse waveform. Radial arterial waveforms were obtained from 45 subjects with no cardiovascular disease and from 56 subjects with hypertension by using radial tonometer (DMP-3000 (with five pressure steps). In this study, it was founded that radial pulse waveform types could be changed by the applied pressure and that the waveform types were different between healthy young people and hypertension patients.