A Study on Compensation of Error Rate in Noninvasive Blood Pressure Measurement System using Tactile Sensor.

The purpose of this paper is to use tactile sensor to compensate the error rate. Most automated sphygmomanometers use oscillometric method and characteristic ratio to estimate systolic and diastolic blood pressure. However, from the face that maximum amplitude of oscillometric waveform and characteristic ratio are affected by compliance of aorta and large arteries, a method to measure the stiffness of arteries by using tactile sensor was chosen in order to integrate it with sphygmomanometer in the future instead of using photoplethysmography. Since tactile sensor is very weak in movements, efforts were made to maintain subject's arm fixed, and 40Hz low pass filter was used to eliminate noise from power source and high frequency noise. Analyzing program was made to get time delay between first and second peak of averaged digital volume pulse(ΔTDVP), and subject's height was divided by ΔTDVP to calculate stiffness index of arteries(SIDVP). Regression equations of systolic and diastolic pressure using SIDVP and mean arterial pressure(MAP) were computed from the training set(23 subjects) among total 46 subjects(age: 26.80±3.12, male: female = 32: 14) and were tested in 61 subjects to compensate error rate. Error rate in total subjects were systolic 6.51±9.25mmHg, diastolic 3.83±11.67mmHg, and those in the test setv were −5.50±9.27mmHg and 4.34±10.80mmHg each. Consequently, error rates were compensated especially in diastolic pressure using SIDVP, various slopes from digital volume pulse and MAP to systolic 2.57±8.05mmHg and diastolic 2.08±8.75mmHg. [ABSTRACT FROM AUTHOR]