• Korean Circulation Journal
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• v.52 no.3
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• pp.198-204
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• 2022

Blood pressure measurement (BPM) is an essential part of medical examination, and therefore accuracy of BPM devices is crucial. Over the past few years, there has been a rise in new BPM techniques using photoplethysmographic (PPG) signals and complex algorithms for blood pressure estimation. Especially the combination of a mobile device or a smartphone with a camera using PPG may potentially revolutionize BPM in the future. The first-ever BPM application to be approved as a medical device was one by the Korean Ministry of Food and Drug Safety in 2020, despite the lack of robust scientific evidence proving its validity. While the prospect of using these novel BPM devices is an opportunity, there are also some critical issues around calibration and utility in different patient groups that need to be resolved before they can be incorporated into daily clinical practice.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.859-860
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• 2006

We developed a cuffless and noninvasive measurement technique of blood pressure using tonometric pressure sensor. With observation that the maximum value of 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 tisse. Detecting only one part of the body and using only one device are quite advantageous over other BP measurement techniques. Our technique makes new way for the cuffless BP measurement.

• Journal of Sensor Science and Technology
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• v.26 no.4
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• pp.239-244
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• 2017

Noninvasive, cuffless, and continuous blood pressure (BP) monitoring is essential to prevent and control hypertension. A well-known existing method for this measurement is pulse transit time (PTT), which has been investigated by many researchers as a promising approach. However, the fundamental principle of the PTT method is based on the time interval taken by a pulse wave to propagate between the proximal and distal arterial sites. Consequently, this method needs an independent system with two devices placed at two different sites, which is a problem. Even though some studies attempted to synchronize the system, it is bulky and inconvenient by contemporary standards. To find a more sensitive method to be used in a BP measurement device, this study used radial electrical bioimpedance (REB) as a potential indicator for BP determination. Only one impedance plethysmography channel at the wrist is performed for demonstrating a ubiquitous BP wearable device. The experiment was evaluated on eight healthy subjects with the ambulatory BP monitor on the upper arm as a reference. The results demonstrated the potential of the proposed method by the correlation of estimated systolic (SBP) and diastolic (DBP) BP against the reference at $0.84{\pm}0.05$ and $0.83{\pm}0.05$, respectively. REB also tracked the DBP well with a root-mean-squared-error of $7.5{\pm}1.35mmHg$.

• Korean Circulation Journal
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• v.54 no.2
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• pp.105-107
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• 2024

• Korean Circulation Journal
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• v.54 no.2
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• pp.93-104
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• 2024

Backgrounds and Objectives: This study aimed to evaluate the applicability and precision of a ring-type cuffless blood pressure (BP) measurement device, CART-I Plus, compared to conventional 24-hour ambulatory BP monitoring (ABPM). Methods: Forty patients were recruited, and 33 participants were included in the final analysis. Each participant wore both CART-I Plus and ABPM devices on the same arm for approximately 24 hours. BP estimation from CART-I Plus, derived from photoplethysmography (PPG) signals, were compared with the corresponding ABPM measurements. Results: The CART-I Plus recorded systolic blood pressure (SBP)/diastolic blood pressure (DBP) values of 131.4±14.1/81.1±12.0, 132.7±13.9/81.9±11.9, and 128.7±14.6/79.3±12.2 mmHg for 24-hour, daytime, and nighttime periods respectively, compared to ABPM values of 129.7±11.7/84.4±11.2, 131.9±11.6/86.3±11.1, and 124.5±13.6/80.0±12.2 mmHg. Mean differences in SBP/DBP between the two devices were 1.74±6.69/-3.24±6.51 mmHg, 0.75±7.44/-4.41±7.42 mmHg, and 4.15±6.15/-0.67±5.23 mmHg for 24-hour, daytime, and nighttime periods respectively. Strong correlations were also observed between the devices, with r=0.725 and r=0.750 for transitions in SBP and DBP from daytime to nighttime, respectively (both p<0.001). Conclusions: The CART-I Plus device, with its unique ring-type design, shows promising accuracy in BP estimation and offers a potential avenue for continuous BP monitoring in clinical practice.

• Journal of the Korean Magnetics Society
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• v.21 no.3
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• pp.104-107
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• 2011

We measured signals at the "Guan" region of a radially arterial pulse using the prototype of a clamping pulsimeter equipped with a Hall effect device, which is passed signals through the voltage detecting hard ware system. The important four different measuring times of the period, systolic, reflective, and notch peaks for a temporally pulse signal are obtained and compared each other from the analysis for an arbitrary pulse wave of one position of small size permanent magnet. It is possible to measure the reproducible pulse rate and blood pressure by using the cuffless clip type pulsimeter without an unpleasant oppressive feeling due to the use of pressurization.