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

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.1926-1938
• /
• 2009

In this study, detection system of the blood flow variation rate was implemented using the variation effect of bio electric impedance at time of the blood pressure measurement by means of impedance method. The blood pressure measurement was performed by the oscillometric method. The mean arterial pressure was calculated using maximum amplitude algorithm. The systolic and diastolic pressure were estimated by establishment of the various characteristic ratio according to mean arterial pressure range. Alternative static current source and lock_in amplifier were introduced to impedance measurement. The variation of blood volume was measured using variation bio impedance according to induced cuff pressure at measuring area.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.1
• /
• pp.136-141
• /
• 2007

The Purpose Of This Paper Is To Use A Tactile Sensor To Compensate The Error Rate. Most Automated Sphygmomanometers Use The Oscillometric Method And Characteristic Ratio To Estimate Systolic And Diastolic Blood Pressure. However, Based On The Fact That Maximum Amplitude Of The Oscillometric Waveform And Characteristic Ratio Are Affected By Compliance Of The Aorta And Large Arteries, A Method To Measure The Artery Stiffness By Using A Tactile Sensor Was Chosen In Order To Integrate It With The Sphygmomanometer In The Future Instead Of Using Photoplethysmography. Since Tactile Sensors Have Very Weak Movements, Efforts Were Made To Maintain The Subject's Arm In A Fixed Position, And A 40hz Low Pass Filter Was Used To Eliminate Noise From The Power Source As Well As High Frequency Noise. An Analyzing Program Was Made To Get Time Delay Between The First And Second Peak Of The Averaged Digital Volume Pulse(${\Delta}t_{dvp}$), And The Subject's Height Was Divided By ${\Delta}t_{dvp}$ To Calculate The Stiffness Index Of The Arteries($Si_{dvp}$). Regression Equations Of Systolic And Diastolic Pressure Using $Si_{dvp}$ And Mean Arterial Pressure(Map) Were Computed From The Test Group (60 Subjects) Among A Total Of 121 Subjects(Age: $44.9{\pm}16.5$, Male: Female=40:81) And Were Tested In 61 Subjects To Compensate The Error Rate. Error Rates Considering All Subjects Were Systolic $4.62{\pm}9.39mmhg$, And Diastolic $14.40{\pm}9.62mmhg$, And Those In The Test Set Were $3.48{\pm}9.32mmhg,\;And\;14.34{\pm}9.67mmhg$ Each. Consequently, Error Rates Were Compensated Especially In Diastolic Pressure Using $Si_{dvp}$, Various Slopes From Digital Volume Pulse And Map To Systolic-$1.91{\pm}7.57mmhg$ And Diastolic $0.05{\pm}7.49mmhg$.

• Journal of Biomedical Engineering Research
• /
• v.24 no.4
• /
• pp.281-286
• /
• 2003

Blood Pressure is one of the most fundamental Parameters which reflects physical conditions medically and the blood pressure measurement system using oscillometric method is a Non-Invasive Blood Pressure measurement device by measuring arterial Pressure through a cuff. In this paper. we designed a inflatable wrist blood pressure system which measures blood Pressure during the stepping inflation in the wrist cuff. The hardware system consists of a main power unit, a bladder in cuff unit, signal detection units, signal Processing units. a wireless data transmission unit, and a data display unit. We evaluated the reliability of this system by comparing and analyzing systolic. diastolic blood Pressure, and heart rate with other commercial blood Pressure measurement devices. Characteristic ratio values used to determine systolic and diastolic blood Pressure using MAA(Maximum Amplitude Algorithm) were 0.436 and 0.671 respectively.

• Clinical and Experimental Pediatrics
• /
• v.51 no.9
• /
• pp.998-1006
• /
• 2008

Purpose : Hypertension is defined as average systolic blood pressure and/or diastolic blood pressure that is ${\geq}95^{th}$ percentile for gender, age, and height on ${\geq}three$ occasions. Knowing that blood pressure values increase in children as they grow older, the purposes of this study were to measure blood pressure by an oscillometric device and to determine normal values and percentile curves for children. Methods : Systolic and diastolic blood pressures were measured twice with an oscillometric device in 3,545 boys and 3,145 girls under six years of age, in Seoul. Using this data, we determined average blood pressure values and percentile curves based on gender and age; we subdivided these values into blood pressures of $50^{th}$, $90^{th}$, $95^{th}$, and $99^{th}$ percentiles, by percentile of height. The regression coefficients and standard deviations of the systolic and diastolic blood pressure values were obtained from linear regression models. Results : Older boys and girls had higher systolic and diastolic blood pressure values. Older boys and girls in the same percentile of height for age had higher systolic and diastolic blood pressure values. Taller boys and girls within the same age group had higher systolic and diastolic blood pressure values. Conclusion : Blood pressure standards based on gender, age, and height were obtained via an oscillometric method. Llimitation of this study is that the study population was not from the whole country, but exclusively from Seoul. Nonetheless, the data from this study will be helpful in diagnosing and managing hypertension in Korean children.

• Journal of Biomedical Engineering Research
• /
• v.29 no.3
• /
• pp.239-248
• /
• 2008

In this study, a new method using a capacitive sensor and an adaptive filter was proposed to deal with artifacts contaminating an oscillation signal in oscilometric blood pressure measurement. The proposed method makes use of a variation of the capacitance between an electrode fixed to a cuff and an external object to detect artifacts caused by the external object bumping into the cuff. The proposed method utilizes the adaptive filter based on linear prediction to remove the detected artifacts. The conventional method using linear interpolation and the proposed method using the adaptive filter were applied to three types of the artifact-contaminated oscillation signals(no overlap, non-consecutive overlap, and consecutive overlap between artifacts and oscillations) to compare them in terms of the artifact reduction performance. The proposed method was more robust than the conventional method in the case of consecutive overlap between artifacts and oscillations. The proposed method could be useful for measuring blood pressure in such a noisy environment that the subject is being transported.

• Journal of Biomedical Engineering Research
• /
• v.20 no.4
• /
• pp.461-469
• /
• 1999

In this paper, an ECG-NIBP patient monitor is designed. This is an essential equipment to measure and monitor patient's physical condition - electrocardiogram(ECG) wave, heart rate(HR), and noninvasive blood pressure(NIBP) - in ICU, CCU, and operating room. The ECG is an electrical waveform produced by relaxation and contraction of the cardiac muscle. Most physicians diagnose patient's cardiac states from ECG pattern. A blood pressure is one of the clinical indexes measured in a emergency room or operating room. In this paper, the blood pressure is measured in artery by using the nonivasive oscillometric method. The developed patient monitor was inspected and compared with other instruments in operating rooms. The results were 1bpm of maximum difference in the heart rate, 15mmHg in the systolic pressure, 16mmHg in the diastolic pressure, and 25mmHg in the mean blood pressure. But the total results were 0.15bpm of the mean difference in the heart rate, 5mmHg in the systolic pressure, 10mmHg in the diastolic pressure, and 9mmHg in the mean blood pressure. The designed ECG-NIBP patient monitor can measure the ECG wave, HR, and BP. And the multi-tasking module of pulse oximetry . respiration . temperature monitor will be added in the near future.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.9 no.1
• /
• pp.101-112
• /
• 2002

Purpose: This study evaluated the accuracy of electronic devices compared with mercury sphygmomanometer. Of 132 outpatients with electronic devices. 77 who possessed oscillometric cuff devices participated in this study. Method: When the blood pressure was measured, all electronic devices were connected by means of a Y-connector to a mercury sphygmomanometer. Using the simultaneous same arm approach, each comparison was carried out three times at 2-minute intervals. Results: Compared with the mercury sphygmomanometer, the electronic devices underestimated systolic and diastolic blood pressure, respectively by $4.0{\pm}5.8mmHg$ and $2.5{\pm}67mmHg$, which satisfies the standard error range of the American Association for the Advancement of Medical Instrumentation. According to the British Hypertension Society criteria, these differences achieved C grade for both systolic and diastolic pressure. For the graphical analysis, the differences had a tendency to fulfill the permitted error limits in both diastolic and systolic blood pressure. Moreover, the purchase duration was not correlated with the accuracy of electronic devices. Conclusion: These results indicate that difference in blood pressure between electronic devices and mercury sphygmomanometer is within the standard error. Therefore, electronic blood pressure measuring devices may be useful for therapeutic self-management of hypertension.

• Korean Journal of Community Nutrition
• /
• v.1 no.2
• /
• pp.178-188
• /
• 1996

Blood pressure distribution of adolescents and its several related factors including obesity were investigated through blood pressure measuring by automated oscillometric method, anthropometry, and questionnaire. Subjects were 480 female and 480 male middle school students living in Taejon. Mean values of systolic(SBP)/diastolic(DNP) blood pressure of male and female students were 118.4$\pm$11.0/69.5$\pm$9.6 mmHg and 116.9$\pm$10.4/69.5$\pm$8.6 mmHg, respectively. Their blood pressures, particularly SBP, increased with age and showed higher value in the males than in the females. All frequency distributions of SBP and DBP, by sex and age, showed normal curves and their 50th, 90th, and 95th percentiles were presented. As obese index increased, both SBP and DBP were elevated and the prevalence of hypertension which was classified by Task Force Report(1987) increased, particularly in male students. Body weight and BMI were positively correlated with both SBP and DBP, and hight was also positively correlated with SBP or DBP. Our data inicated that blood pressure and hypertension prevalence of adolescents tended to increase and various internal and external environmental factors affected them. It was emphasized that blood pressure measurement should be done in every medical examination of adolescents and the nationwide Korean standard of blood pressure for adolescents have to be prepared. (Korean J Community Nutrition 1(2) : 178-188, 1996)

• Transactions on Electrical and Electronic Materials
• /
• v.9 no.1
• /
• pp.38-43
• /
• 2008

Using an arterial pressure-volume (APV) model, we performed an analysis of the conventional blood pressure estimation method using an oscillometric sphygmomanometer with computer simulation. Traditionally, the maximum amplitude algorithm (MAA) has been applied to the oscillation waveforms of the APV model to obtain the mean arterial pressure and the characteristic ratio. The estimation of mean arterial pressure and characteristic ratio was significantly affected by the shape of the blood pressure waveforms and the cutoff frequency of high-pass filter (HPF) circuitry. Experimental errors result from these effects when estimating blood pressure. To determine an algorithm independent of the influence of waveform shapes and parameters of HPF, the volume oscillation of the APV model and the phase shift of the oscillation with fast Fourier transform (FFT) were tested while increasing the cuff pressure from 1 mmHg to 200 mmHg (1 mmHg/s). The phase shift between ranges of volume oscillation was then only observed between the systolic and the diastolic blood pressures. The same results were obtained from simulations performed on two different arterial blood pressure waveforms and one hyperthermia waveform.