Vital Sign Measurement Using FBG Sensor for New Wearable Sensor Development

In this study, we measured the vital signs of a living body using an FBG sensor by installing it at a pulsation point such as the radial artery. We developed a biological model to demonstrate the capability of an FBG sensor. The FBG sensor signal was found to correspond to the changes in diameter of the artery caused by the pressure of the blood flow. Vital signs such as pulse rate, respiratory rate, stress load, and blood pressure were calculated from the FBG sensor signal. While pulse rate and respiration rate were calculated by peak detection of FBG sensor signal. Blood pressure was calculated from the waveform shape of one beat of the FBG sensor signal by PLS regression analysis. All vital signs were calculated with high accuracy. The study helps establish that these vital signs can be calculated continuously and simultaneously. Considering that an FBG sensor can detect a strain with high sensitivity using a small optical fiber, it is expected to be adopted widely as a novel wearable vital sign sensor

Sensores de fibra ótica como tecnologia não-invasiva para avaliação da pressão arterial central

Doutoramento em Engenharia FísicaCom o presente trabalho pretendeu-se explorar soluções de fibra ótica na aquisição da onda de pulso na artéria carótida, para análise da sua morfologia e cálculo da pressão arterial central. Foram desenvolvidos três sistemas, dois baseados em redes de Bragg, gravadas em fibra de sílica, e outro em modulação de intensidade, usando fibra ótica de plástico. O primeiro sensor foi desenvolvido com o objetivo de testar a exequibilidade da utilização de fibra ótica nesta aplicação. Após resultados promissores da sua caracterização e testes em sujeitos, o desenvolvimento dos dois sensores consequentes teve por objetivo o aumento da sensibilidade e facilidade de utilização das sondas, pela melhoria da sua forma, portabilidade e autonomia. A solução baseada em intensidade mostrou-se ainda como um sistema que coligava desempenho a baixo custo, tendo por isso sido submetida a um estudo pré-clínico, comparando o seu desempenho ao de um dispositivo comercial, de natureza eletromecânica, numa pequena coorte de indivíduos saudáveis. Este estudo teve como objetivo investigar a correlação dos resultados obtidos com a sonda de fibra ótica e o dispositivo comercial. Tendo-se obtido uma correlação muito forte entre as duas técnicas, o dispositivo foi proposto para avaliação clínica. O desempenho da sonda foi assim comparado a um dispositivo comercial, numa coorte de indivíduos hipertensos. Foram também levados a cabo testes invasivos, usando como referência ondas de pressão obtidas no lúmen da artéria aorta em contexto de cateterismo cardíaco. Em ambos os estudos clínicos foram obtidos coeficientes de correlação muito fortes e diferenças de pressão média na gama obtida para dispositivos comerciais. Conclui-se assim que o dispositivo baseado em modulação de intensidade surge como uma promissora alternativa de baixo custo aos dispositivos eletromecânicos de avaliação de pressão arterial central disponíveis no mercado.The present study aimed to explore fibre optic solutions in the acquisition of the pulse wave in the carotid artery, to its morphology analysis and central arterial pressure calculation. Three systems were developed, two based on Bragg gratings, engraved in silica fibre, and another on intensity modulation, using plastic optical fibre. The first sensor was developed in order to test the feasibility of the fibre optics use in this application. After promising results in the characterization and small tests in subjects, the development of the consequent two sensors had as main goals increasing the probes sensitivity and user-friendliness, by improving its shape, portability and autonomy. The intensity-based solution proved to be the system that best combined performance to low cost, and thus was subjected to a pre-clinical study, comparing its performance to a commercial device in a small cohort of healthy individuals. This study aimed to investigate the correlation between the results obtained with the fibre optic probe and the commercial device. Having been obtained a very strong correlation between the two techniques, the device was proposed for clinical evaluation. The probe’s performance was therefore compared to a non-invasive commercial device, in a cohort of hypertensive individuals. Invasive testing was also performed, using as reference pressure waves obtained in the lumen of the aortic artery in cardiac catheterization context. In both trials very strong correlation coefficients were obtained, as well as medium pressure differences in the range verified for commercial devices. It is concluded that the device based on intensity modulation arises as promising low cost alternative to central arterial pressure assessment electromechanical devices available in the market

Singlemode-Multimode-Singlemode Optical Fiber Sensor for Accurate Blood Pressure Monitoring

A dual-channel single-mode-multi-mode-single-mode (SMS) fiber optic sensor encapsulated by polydimethylsiloxane (PDMS) was proposed for the first time, for the simultaneous monitoring of the brachial and radial arteries for accurate blood pressure prediction. With the help of the machine learning algorithm Support Vector Regression (SVR), the SMS fiber sensor can continuously and accurately monitor the systolic and diastolic blood pressure. Commercial sphygmomanometers are used to calibrate the accuracy of blood pressure measurement. Compared with the single-channel system, this system can extract more pulse wave features for blood pressure prediction, such as radial artery transit time (RPTT), brachial artery transit time (BPTT), and the transit time difference between the radial artery and the brachial artery (DBRPTT). The results show that the performance of dual-channel blood pressure monitoring is more accurate than that of single-channel blood pressure monitoring in terms of the absolute value of the correlation coefficient (R) and the average value of the difference between SBP and DBP. In addition, both the single-channel and dual-channel blood pressure monitoring are in line with the Association for the Advancement of Medical Devices (AAMI), but the average deviation (DM, 0.06 mmHg) and standard deviation (SD, 1.54 mmHg) of dual-channel blood pressure monitoring are more accurate. The blood pressure monitoring system has the characteristics of low cost, high sensitivity, non-invasive and capability for remote real time monitoring, which can provide effective solution for intelligent health monitoring in the era of artificial intelligence in the future

Fiber bragg gratings for medical applications and future challenges: A review

In the last decades, fiber Bragg gratings (FBGs) have become increasingly attractive to medical applications due to their unique properties such as small size, biocompatibility, immunity to electromagnetic interferences, high sensitivity and multiplexing capability. FBGs have been employed in the development of surgical tools, assistive devices, wearables, and biosensors, showing great potentialities for medical uses. This paper reviews the FBG-based measuring systems, their principle of work, and their applications in medicine and healthcare. Particular attention is given to sensing solutions for biomechanics, minimally invasive surgery, physiological monitoring, and medical biosensing. Strengths, weaknesses, open challenges, and future trends are also discussed to highlight how FBGs can meet the demands of next-generation medical devices and healthcare system

Fiber Bragg Gratings for Medical Applications and Future Challenges: A Review

[EN] In the last decades, fiber Bragg gratings (FBGs) have become increasingly attractive to medical applications due to their unique properties such as small size, biocompatibility, immunity to electromagnetic interferences, high sensitivity and multiplexing capability. FBGs have been employed in the development of surgical tools, assistive devices, wearables, and biosensors, showing great potentialities for medical uses. This paper reviews the FBG-based measuring systems, their principle of work, and their applications in medicine and healthcare. Particular attention is given to sensing solutions for biomechanics, minimally invasive surgery, physiological monitoring, and medical biosensing. Strengths, weaknesses, open challenges, and future trends are also discussed to highlight how FBGs can meet the demands of next-generation medical devices and healthcare system.This work was supported in part by INAIL (the Italian National Institute for Insurance against Accident at Work), through the BRIC (Bando ricerche in collaborazione) 2018 SENSE-RISC (Sviluppo di abiti intelligENti Sensorizzati per prevenzione e mitigazione di Rischi per la SiCurezza dei lavoratori) Project under Grant ID10/2018, in part by the UCBM (Universita Campus Bio-Medico di Roma) under the University Strategic HOPE (HOspital to the PatiEnt) Project, in part by the EU Framework Program H2020-FETPROACT-2018-01 NeuHeart Project under Grant GA 824071, by FCT/MEC (Fundacao para a Ciencia e Tecnologia) under the Projects UIDB/50008/2020 - UIDP/50008/2020, and by REACT (Development of optical fiber solutions for Rehabilitation and e-Health applications) FCT-IT-LA scientific action.Lo Presti, D.; Massaroni, C.; Leitao, CSJ.; Domingues, MDF.; Sypabekova, M.; Barrera, D.; Floris, I.... (2020). Fiber Bragg Gratings for Medical Applications and Future Challenges: A Review. IEEE Access. 8:156863-156888. https://doi.org/10.1109/ACCESS.2020.3019138S156863156888

Optical Fiber Interferometric Sensors

The contributions presented in this book series portray the advances of the research in the field of interferometric photonic technology and its novel applications. The wide scope explored by the range of different contributions intends to provide a synopsis of the current research trends and the state of the art in this field, covering recent technological improvements, new production methodologies and emerging applications, for researchers coming from different fields of science and industry. The manuscripts published in the Special issue, and re-printed in this book series, report on topics that range from interferometric sensors for thickness and dynamic displacement measurement, up to pulse wave and spirometry applications

Development of pulse diagnostic devices in Korea

AbstractIn Korean medicine, pulse diagnosis is one of the important methods for determining the health status of a patient. For over 40 years, electromechanical pulse diagnostic devices have been developed to objectify and quantify pulse diagnoses. In this paper, we review previous research and development for pulse diagnostic devices according to various fields of study: demand analysis and current phase, literature studies, sensors, actuators, systems, physical quantity studies, clinical studies, and the U-health system. We point out some confusing issues that have been naively accepted without strict verification: original pressure pulse waveform and derivative pressure pulse waveform, pressure signals and other signal types, and minutely controlled pressure exertion issues. We then consider some technical and clinical issues to achieve the development of a pulse diagnostic device that is appropriate both technically and in terms of Korean medicine. We hope to show the history of pulse diagnostic device research in Korea and propose a proper method to research and develop these devices

Evaluation of pulse transit time for different sensing methodologies of arterial waveforms.

We perform a novel comparative analysis between optically and mechanically derived pulse transit time (PTT), which is a universally employed technique for cuffless blood pressure (BP) estimation. Two inline photoplethysmogram (PPG) sensors were placed at the distal and proximal phalanxes of the index finger, and two finger ballistocardiogram (BPP) sensors were wrapped on top of the PPG sensors fixture around the phalanxes of the index finger. The stacking of the BPP sensor over the PPG sensor provided vertical spatial alignment for same location acquisition of the blood flow waveform through the radial artery. The analysis of variance (ANOVA) between PTT derived from the PPG and BPP sensors resulted in a statistically significant difference at p < 0.05. The PTT derived from the BPP sensors showed higher values (17.8 milliseconds on average) than the PTT derived from the PPG sensors. Higher accuracy PTT values will improve the estimation of cuffless BP and thus has the potential to revolutionize the technology