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

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 23; p. 5088
• Main Authors: Haseda, Yuki, Bonefacino, Julien, Tam, Hwa-Yaw, Chino, Shun, Koyama, Shouhei, Ishizawa, Hiroaki
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.11.2019; MDPI
• Subjects: Algorithms; Blood pressure; Blood Pressure - physiology; Blood Pressure Determination - instrumentation; Calibration; fiber bragg grating; Gravity; Heart rate; Heart Rate - physiology; Humans; Least-Squares Analysis; non-invasive measurement; Optical Fibers; partial least squares regression; Physical Phenomena; plastic optical fiber; Plastics - chemistry; Polymethyl methacrylate; pulse wave signals; Reproducibility of Results; Sensors; Signal Processing, Computer-Assisted - instrumentation; Veins & arteries; Vital signs; non-invasive measurement; blood pressure; plastic optical fiber; fiber Bragg grating; partial least squares regression; pulse wave signals
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19235088

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.