양손 임피던스법에 의한 SV 측정의 정확도 향상을 위한 연구

윤찬솔(Chan-Sol Yoon),염호준(Ho-Jun Yeom) 대한전기학회 2015 전기학회논문지 Vol.64 No.8

The purpose of this study is to measurement the cardiac output using hand to hand impedance method to provide convenience to user when measuring SV(stroke volume) with the use of ICG(Impedance Cardiography). We suggest the optimized modified formula, which can be applied when using impedance with the use of hand to hand Impedance. To verify this formula, a SV from transthoracic approach and hand to hand approach are compared for the 36 subjects, respectively. The acquired data was analyzed by using LabVIEW 8.6, analysis was implemented by SPSS 12.0. Fine difference was shown by individual. We showed that as a result of analyzing the ICG measurement value on thoracic and hand to hand, the correlation with SV was r=0.716, thereby having indicated the results of regression model in relatively high correlation.

Preceding Research for Estimating the Maximal Fat Oxidation Point through Heart Rate and Heart Rate Variability

Myeong-Heon Sim(심명헌),Min-Yong Kim(김민용),Sol-Chan Yoon(윤찬솔),Joo-Hong Chung(정주홍),Yeon-Sik Noh(노연식),Sung-Bin Park(박성빈),Hyung-Ro Yoon(윤형로) 대한전기학회 2012 전기학회논문지 Vol.61 No.9

Increasing the oxidation of fat through exercise is the recommendable method for weight control. Preceding researches have proposed increase in the usage of fat during exercise in stabilized state and under maximum exertion through aerobic training. However, such researches require additional equipment for gas analysis in order to measure the caloric value or gas exchange of subjects during exercise. Such equipments become highly restrictive for those exercise and cause substantially higher cost. According to this, we have presented the method of estimating the maximal fat oxidation point through changes in LF & HF which reflects changes in heart rate and the autonomic nervous system in order to induce exercise for a less restrictive and efficient fat oxidation than existing methods. We have conducted exercise stress test on subject with similar exercise abilities, and have detected the changes in heart rate and changes in LF & HF by measuring changes in fat oxidation and measuring ECG signals at the same time through a gas analyzer. Changes in heart rate and HRV of the subjects during exercising was detected through only the electrocardiographic signals from exercising and detected the point of maximum fat oxidation that differs from person to person. The experiment was carried out 16 healthy males, and used Modified Bruce Protocol, which is one of the methods of exercise stress test methods that use treadmill. The fat oxidation amount during exercise of all the subjects showed fat oxidation of more than 4Fkcal/min in the exercise intensity from about 5 minutes to 10 minutes. The correlation between the maximal fat oxidation point obtained through gas analysis and the point when 60% starts to be relevant in the range from -0.01 to 0.01 seconds for values of R-R interval from changes in heart rate had correlation coefficients of 0.855 in Kendall’s method and in Spearman’s rho, it showed significant results of it being p<0.01 with 0.950, respectively. Furthermore, in the changes in LF & HF, we have determined the point where the normalized area value starts to become the same as the maximal fat oxidation point, and the correlation here showed 0.620 in Kendall and 0.780 in Spearma of which both showed significant results as p<0.01.

전기적 임피던스 방법을 통한 hand-held 타입의 심박출량 모니터링 시스템 개발 및 검증

서광석(Kwang-seok.Seo),심명헌(Myeong-Heon Sim),김민용(Min-Yong Kim),윤찬솔(Chan-Sol Yoon),정주홍(Joo-Hong Chung),박성빈(Sung-Bin Park),윤형로(Hyung-Ro Yoon) 대한전기학회 2012 전기학회논문지 Vol.61 No.12

The impedance cardiogram has been proposed as a non-invasive, continuous, operator independent, and cost-effective method for cardiac output monitoring. However, it can not be completely considered as non-restrictive method beacuse of attached spot and band type electrodes. Therefore, we developed a improved convenient hand-held typed measurement system for cardiac output by electrical impedance technique. 80 subjects from Yonsei University and the surrounding areas, participated. All subjects measured stroke volume and cardiac output through Physioflow and developed system. To verify the developed system, statistical methods such as correlation, Wilcoxon signed ranks test, and the Bland-Altman analysis were used. The proposed system showed significant correlation in both male and female stroke volume(r=0.715, r=0.704) and cardiac output(r=0.826; r=0.804). From these results, it can be concluded that stroke volume and cardiac output could be improved convenient measurement using the both hands without the help of a specialist.

Improvement of the Accuracy of Wrist Noninvasive Blood Pressure Measurement Using Multiple Bio-signals

정운모(Woon-Mo Jung),심명헌(Myeong-Heon Sim),정상오(Sang-O Jung),김민용(Min-Yong Kim),윤찬솔(Chan-Sol Yoon),정인철(In-Chol Jung),윤형로(Hyung-Ro Yoon) 대한전기학회 2011 전기학회논문지 Vol.60 No.8

The blood pressure measuring equipment, which is being supplied and used most widely by being recognized convenience and accuracy now generally, is oscillometric blood pressure monitor. However, a change in blood pressure is basically influenced by diverse elements such as each individual’s physiological status and physical condition. Thus, the measurement of blood pressure, which used single element called oscillation in blood pressure of being conveyed to cuff, is not considered on physiological elements such as cardiovascular system status and blood vessel stiffness index, and on external elements, thereby being quite in error. Accordingly, this study detected diverse bio-signals and body informations in each individual as the measurement subject such as ECG, PPG, and Korotkoff Sound in order to enhance convenience and accuracy of measuring blood pressure in the complex measurement equipment, thereby having extracted regression method for compensation in error of oscillometric blood pressure measurement on the wrist, and having improved accuracy of measuring blood pressure. To verify a method of improving accuracy, the blood pressure value in each of SBP, DBP, MAP was acquired through 4-stage experimental procedure targeting totally 51 subjects. Prior to experiment, the subjects were divided into two groups such as the experimental group for extracting regression method and the control group for verifying regression method. Its error was analyzed by comparing the reference blood pressure value, which was obtained through the auscultatory method, and the oscillometric blood pressure value on the wrist. To reduce the detected error, the blood pressure compensation regression method was calculated through multiple linear regression analysis on elements of blood pressure, individual body information, PTT, HR, K-Sound PSD change. Verification was carried out on improving significance and accuracy by applying the regression method to the data of control group. In the experimental results, as a result of confirming error on the reference blood pressure value in SBP, DBP, and MAP, which were acquired through applying regression method, the results of -0.47±7.45 ㎜Hg, -0.23±7.13 ㎜Hg, 0.06±6.39 ㎜Hg could be obtained. This is not only the numerical value of satisfying the sphygmomanometer reference of AAMI, but also shows the lower result than the numerical value in SBP : -2.5±12.2 ㎜Hg, DBP : -7.5±8.4 ㎜Hg, which is the mean error in the experimental results of Brram’s research for verifying accuracy of Omron RX-M, which shows relatively high accuracy among wrist sphygmomanometers. Thus, the blood pressure compensation could be confirmed to be made within significant level.

양손 전극의 임피던스법을 이용한 심박출량 측정의 최적화

정상오(Sang-O Jung),심명헌(Myeong-Heon Sim),정운모(Woon-Mo Jung),김민용(Min-Yong Kim),윤찬솔(Chan-Sol Yoon),윤형로(Hyung-Ro Yoon) 대한전기학회 2011 전기학회논문지 Vol.60 No.9

In this study, a new method that can estimate ICG data from a subject’s both hands to measure Cardiac Output under convenient sensor environment. With this aim, a grip-type electrode was implemented to measure ICG. To improve the accuracy of measurement, the regression equation was extracted using multiple bio-parameters and our result was compared with the thoracic ICG equipment(Physio Flow<SUP>ⓡ</SUP>, PF104D, Manatec Biomedical, France), which is being used in clinics. The subjects consist of 26 men and 4 women(age in 22.0±3.32). They are no cardiac disease. Parameters available for regression model were used gender, BMI, MBP, LVET, dZ/dt(max), distance between the measured electrodes, body impedance, and PTT. As a result of analyzing the ICG measurement value on thorax and both hands, the correlation with stroke volume, heart rate, and cardiac output was R²=0.853, R²=0.958 and R²=0.899, respectively.