scholarly journals Measurement of Pulse Wave Signals and Blood Pressure by a Plastic Optical Fiber FBG Sensor

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5088 ◽  
Author(s):  
Yuki Haseda ◽  
Julien Bonefacino ◽  
Hwa-Yaw Tam ◽  
Shun Chino ◽  
Shouhei Koyama ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Optical Fiber ◽  
Calibration Curve ◽  
Pulse Wave ◽  
Blood Pressure Measurement ◽  
Plastic Optical Fiber ◽  
Fbg Sensor ◽  
Wide Range ◽  
Silica Optical Fiber ◽  
Fbg Sensors

Fiber Bragg grating (FBG) sensors fabricated in silica optical fiber (Silica-FBG) have been used to measure the strain of human arteries as pulse wave signals. A variety of vital signs including blood pressure can be derived from these signals. However, silica optical fiber presents a safety risk because it is easily fractured. In this research, an FBG sensor fabricated in plastic optical fiber (POF-FBG) was employed to resolve this problem. Pulse wave signals were measured by POF-FBG and silica-FBG sensors for four subjects. After signal processing, a calibration curve was constructed by partial least squares regression, then blood pressure was calculated from the calibration curve. As a result, the POF-FBG sensor could measure the pulse wave signals with an signal to noise (SN) ratio at least eight times higher than the silica-FBG sensor. Further, the measured signals were substantially similar to those of an acceleration plethysmograph (APG). Blood pressure is measured with low error, but the POF-FBG APG correlation is distributed from 0.54 to 0.72, which is not as high as desired. Based on these results, pulse wave signals should be measured under a wide range of reference blood pressures to confirm the reliability of blood pressure measurement uses POF-FBG sensors.

scholarly journals Influence on Calculated Blood Pressure of Measurement Posture for the Development of Wearable Vital Sign Sensors

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Shouhei Koyama ◽  
Hiroaki Ishizawa ◽  
Akio Sakaguchi ◽  
Satoshi Hosoya ◽  
Takashi Kawamura
Keyword(s):  
Blood Pressure ◽  
Calibration Curve ◽  
Pressure Measurement ◽  
Pulse Wave ◽  
Blood Pressure Measurement ◽  
Wave Signal ◽  
Fbg Sensor ◽  
Pressure Calculation ◽  
Measurement Height ◽  
The Difference

We studied a wearable blood pressure sensor using a fiber Bragg grating (FBG) sensor, which is a highly accurate strain sensor. This sensor is installed at the pulsation point of the human body to measure the pulse wave signal. A calibration curve is built that calculates the blood pressure by multivariate analysis using the pulse wave signal and a reference blood pressure measurement. However, if the measurement height of the FBG sensor is different from the reference measurement height, an error is included in the reference blood pressure. We verified the accuracy of the blood pressure calculation with respect to the measurement height difference and the posture of the subject. As the difference between the measurement height of the FBG sensor and the reference blood pressure measurement increased, the accuracy of the blood pressure calculation decreased. When the measurement height was identical and only posture was changed, good accuracy was achieved. In addition, when calibration curves were built using data measured in multiple postures, the blood pressure of each posture could be calculated from a single calibration curve. This will allow miniaturization of the necessary electronics of the sensor system, which is important for a wearable sensor.

scholarly journals Photoplethysmography-Based Continuous Systolic Blood Pressure Estimation Method for Low Processing Power Wearable Devices

2019 ◽  
Vol 9 (11) ◽  
pp. 2236 ◽  
Author(s):  
Rolandas Gircys ◽  
Agnius Liutkevicius ◽  
Egidijus Kazanavicius ◽  
Vita Lesauskaite ◽  
Gyte Damuleviciene ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
High Performance ◽  
Pulse Wave ◽  
Blood Pressure Measurement ◽  
Sampling Rate ◽  
Estimation Method ◽  
Wearable Devices ◽  
Wave Steepness ◽  
Processing Power

Regardless of age, it is always important to detect deviations in long-term blood pressure from normal levels. Continuous monitoring of blood pressure throughout the day is even more important for elderly people with cardiovascular diseases or a high risk of stroke. The traditional cuff-based method for blood pressure measurements is not suitable for continuous real-time applications and is very uncomfortable. To address this problem, continuous blood pressure measurement methods based on photoplethysmogram (PPG) have been developed. However, these methods use specialized high-performance hardware and sensors, which are not available for common users. This paper proposes the continuous systolic blood pressure (SBP) estimation method based on PPG pulse wave steepness for low processing power wearable devices and evaluates its suitability using the commercially available CMS50FW Pulse Oximeter. The SBP estimation is done based on the PPG pulse wave steepness (rising edge angle) because it is highly correlated with systolic blood pressure. The SBP estimation based on this single feature allows us to significantly reduce the amount of data processed and avoid errors, due to PPG pulse wave amplitude changes resulting from physiological or external factors. The experimental evaluation shows that the proposed SBP estimation method allows the use of off-the-shelf wearable PPG measurement devices with a low sampling rate (up to 60 Hz) and low resolution (up to 8-bit) for precise SBP measurements (mean difference MD = −0.043 and standard deviation SD = 6.79). In contrast, the known methods for continuous SBP estimation are based on equipment with a much higher sampling rate and better resolution characteristics.

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