• Quality Improvement in Health Care
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• v.3 no.1
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• pp.94-103
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• 1996

Background : Blood pressure is an important indicator in diagnosis and assessing treatment of a patient. Clinical staffs use blood pressure on the assumption that measured value is accurate and reliable. However, whether measured blood pressure is accurate has been rarely investigated in Korea. Objectives : The aims of this study are to evaluate clinical staffs' knowledge and technique as well as accuracy of sphygmomanometer. Also the program to improve the measurement is developed. Methods : Seventy-three registered nurses were asked nine multiple choice questions including Korotkoff sound, cuff size, and deflation rate. Simultaneously characteristics of nurses were examined, age, working place, duration of employment and academic degree. A testing videotape(Standardizing Measurement Video-Tutored Course) was used for evaluating the accuracy of measurement. Testees were to read and record the 12 cases of blood pressure measurement, watching a falling mercury column and hearing Korotkoff sounds. After 10 minutes' education, they were again tested with the same cases. Additionally, 83 mercury sphygmomanometers were checked to find defects such as inaccurate calibration and zero setting, leaky bladder, etc. Results: For the knowledge testing correct response rate was 41.1%. They were the lowest in selecting the proper cuff size and Korotkoff sound. In examining accuracy of blood pressure with videotape, nurses had 67.7% correct response rate. The correct response rate was significantly improved by a session of education. About 23% of sphygmomanometers was without discernable defects. Conclusion : The knowledge and skill of clinical staffs along with the accuracy of equipment have to be improved. A properly designed education program would contribute to the accuracy improvement of blood pressure measurement. Also, more concerns should be given to the precision and maintenance of equipment.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.351-358
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• 2010

In the automatic non-invasive blood pressure measurement device, the oscillometric method iswidely used. In the oscillometric method, the step-wise deflation has the advantage of the robustness for the motion artifacts than the linear deflation method. But it has the disadvantage of its longer measurement time because we need to detect two or more pulses in a certain cuff pressure step. In this study, we suggest the modified step-wise deflation method to overcome this limitation while maintaining the general concept of step-wise deflation. Using one valid pulse in each step and the deflating valve control during the diastolic period, the measurement time could be reduced. In order to verify the accuracy of the proposed algorithm, we compared the blood pressure values from the suggested method and the blood pressure values from the conventional auscultation method. The mean and standard deviation were -0.50${\pm}$5.3mmHg and 2.08${\pm}$4.75mmHg, for systolic and diastolic blood pressure respectively. The measurement time can be reduced up to the half of conventional step-wise deflation method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1606-1616
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• 2011

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 $-0.47{\pm}7.45$ mmHg, $-0.23{\pm}7.13$ mmHg, $0.06{\pm}6.39$ mmHg 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 : $-2.5{\pm}12.2$ mmHg, DBP : $-7.5{\pm}8.4$ mmHg, 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.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.67-73
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• 2019

The blood pressure measurement is calculated as a value corresponding to the pressure of the blood vessel using the pressure from the outside for a long time. Due to the recent miniaturization of measurement equipment and the ICT combination of personal healthcare systems, a system that enables continuous and real-time measurement of blood pressure with a sensor is required. In this study, blood pressure was measured using pulse transit time using Photoplethysmography. In this study, blood pressure was estimated by using systolic blood pressure. And it is possible to make measurement only with PPG itself, which can contribute to making a micro blood pressure measuring device. As a result, systolic blood pressure and PPG's S1-P and P-S2 were used to analyze the possibility of blood pressure estimation.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.23 no.3
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• pp.275-282
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• 2016

Purpose: This study was done to examine the relationship between nursing students' hearing levels and accuracy of blood pressure (BP) measurements. Methods: Participants were 107 students who had finished their fundamental nursing practice and clinical practicum and who used earphones. Data were collected from October 13 to November 30, 2014 and from April 30 to May 19, 2015. Students' hearing thresholds were examined using an audiometer. Students were assigned to take two BP measurements on BP measurement training simulators, but only the second measurement was used for analysis. Results: All nursing students' hearing levels were within normal range, and there was no significant difference found among the settings for diastolic blood pressure. However, there were significant differences between low systolic blood pressure (SBP) (below 120mmHg) and high SBP (over 140mmHg) (z=9.02, p=.011). Measurement error in SBP showed a positive correlation with hearing threshold in the right ear at frequencies of 1000Hz and 500Hz. Conclusion: Findings indicate that BP measurement error is correlated with hearing threshold at some frequencies. To reduce measurement error, nursing students should be provided with health education about hearing and to improve training for students, further studies need to examine other factors influencing BP measurement error.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.693-696
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• 2006

In this study, we made the system to measure variation of blood flow using bio-electrical impedance analysis method. The system, which could measure variation of impedance according to pressure change by artificial pressure, consists of pressure measurement and impedance measurement by 4-electrode method. Pressure measurement splits into semiconducting pressure sensor and electronic circuit for processing output signal. In addition, impedance measurement splits into constant current source circuit and lock-in amplifier for detection impedance signal. We experimented feature of impedance measurement using standard resistance to evaluate the system characteristic. As well as, we experimented to estimate variation of blood flow by measuring impedance and blood flow resistance ratio using mean arterial pressure and variation of blood flow with experimental group. As result of this study, blood flow resistance ratio and variation of blood flow were definitely in inverse proportion and were -0.96776 as correlation coefficient by correlation analysis.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.2
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• pp.30-35
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• 2006

The purpose of this study is to develop a new cuff to improve the accuracy of blood pressure measurement, and to evaluate the performance of the developed system. We added a small bladder to the normal cuff, which we refer to as the double bladder system. The system that we developed for blood pressure measurement was based on the oscillometric method using a double bladder. This system was developed in order to reduce the oscillation noise and to amplify the signal of pure blood pressure. An oscillometric signal database based on the developed system was evaluated according to the ANSI/AAMI/SP10-1992 standard. The correlation coefficients between the cuff of the double bladder and the normal cuff were 0.98 for systolic pressure and 0.94 for diastolic pressure. The mean differences and the standard deviations between the average blood pressure obtained from a mercury manometer and that obtained from an automated sphygmomanometer were -0.7mmHg and 4.9mmHg for systolic, and -1.4mmHg and 5.4mmHg for diastolic pressure. We conclude that the proposed double bladder-based cuff system improves the accuracy of oscillometric blood pressure measurement. The developed system reduces the range of error by about $44{\sim}62%$ for systolic pressure and about $6{\sim}21%$ for diastolic pressure compared to the most recently developed, commercially available sphygmomanometers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.161-168
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• 2018

High blood pressure is main today's adult disease and existing blood pressure gauge is not possible for real-time blood pressure measurement and remote monitoring. But real-time blood pressure monitoring u-healthcare system makes effect health management. In my paper, for monitoring real-time blood pressure, an architecture of real-time blood pressure monitoring system which consisted of wrist type-blood pressure measurement, smart-phone and u-healthcare server is presented. And the analog circuit architecture which is major core function for pulse wave detection and digital hardware architecture for wrist type-blood pressure measurement is presented. Also for software development to operate this hardware system, UML analysis method and flowcharts and screen design for this software design are showed. Therefore such design method in my paper is expected to be useful for real-time blood pressure monitoring u-healthcare system implementation.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.178-186
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• 2007

This study is attempted to correct an error of electronic blood pressure meter with an optical sensor. In general, for a hospitalized patient, ECG, blood pressure, oxygen saturation, and respiration are basically measured to monitor the patient's condition. Opening of a blood vessel after it is occluded by pressurizing the cuff influences the blood flow of peripheral blood vessels as well as oscillation changes in the cuff. Blood vessels are occluded and peripheral blood flow disappears at cuff pressure above the examinee's blood pressure, while blood vessels are opened and peripheral blood flow appears again at cuff pressure under the examinee's blood pressure. Then Disappear-Appear Point Length(DAPL) of peripheral blood flow can be judged with the signal of peripheral blood flow, thus is available as a factor of error correction for electronic blood pressure meter. Also, systolic or diastolic blood pressure can be corrected with Appear-Point-Pressure(APP) of cuff pressure at a point where blood flow occurs and Appear-Maximum Pressure(AMP) of cuff pressure at the maximum amplitude point of peripheral blood flow after peripheral blood flow appears again. For verification, 27 examinees were selected, and their blood value was obtained through experimental procedure of 4 stages including induction of blood pressure change. The examinees were divided into two groups of experimental group and control group, regression analysis was conducted for experimental group, and correction of a blood pressure error was verified with optical signal by applying the regression equation calculated in experimental group to control group. As an experimental result, mean of the whole measurement errors was 5mmHg or more, which did not meet the standard fur blood pressure meter. As a result of correcting blood pressure measurements with data of DAPL, APP, and AMP as drawn out of PPG signal, systolic blood pressure, mean blood pressure, and diastolic blood pressure were $-0.6{\pm}4.4mmHg,\;-1.0{\pm}3.9mmHg$ and $-1.3{\pm}5.4mmHg$, respectively, indicating that mean of the whole measurement errors was greatly improved, and standard deviation was decreased.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.371-375
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• 2008

In blood pressure measurement, the oscillometric method detects and analyzes the pulse pressure oscillation while deflating the cuff around the arm. For its principle, one has to inflate cuff pressure above the subject's systolic pressure and deflate below the diastolic pressure. Most of the commercialized devices inflate until the fixed target pressure and deflate until the fixed completion pressure because there is no way to know the systolic and diastolic pressure before measurement. Too high target pressure makes stress to the subject and too low target pressure makes big error or long measurement time because of re-inflation. There are similar problems for inadequate completion pressure. In this study, we suggest new algorithm to set proper target and completion pressure for each subject by analyzing pressure waveform while inflating period. We compared our proposed method and auscultation method to see the errors of estimation. The differences between the two measurements were -4.02$\pm$4.80mmHg, -10.50$\pm$10.57mmHg and -0.78$\pm$5.l7mmHg for mean arterial pressure, systolic pressure and diastolic pressure respectively. Consequently, we could set the target pressure by 30 mmHg higher than our estimation and we could stop at 20mmHg lower than our estimated diastolic pressure. Using this method, we could reduce the measurement time.