A blood pressure measurement system using fiber optic-based Fabry-Perot interferometer

In this work, the development of a blood pressure (BP) system based on a fiber optic Fabry-Perot interferometer (FFPI) has been investigated. The developed system is consisted of 2 main parts: FFPI structure, and sensing probe, respectively. An aluminum-coated mirror and latex thin film have been used as a reflector and elastic material of the sensing probe. Moreover, the peak detection and also fringe counting techniques have been applied to convert the number of fringes to blood pressure and heart rate values. In addition, a standard digital sphygmomanometer has been utilized as a reference instrument for comparing the performance of FFPI sensor. Eighty-six volunteers aged 21 - 50 years old have been chosen to collect the experimental data. However, the sensing probe has been placed on right side of the neck, and a standard digital sphygmomanometer on the upper left arm of the volunteers. The results indicated that the developed system has ability to measure systolic blood pressure (SBP), and diastolic blood pressure (DBP) in the range of 91 to 128 mmHg, and 62 to 85 mmHg, respectively. Moreover, the heart rate (HR) has also been exploited in the range of 48 to 102 beats/min. By comparing the experimental results with the reference instrument, it found that the average percentage error from the blood pressure measurements is 2.84 %. Furthermore, the developed sensor has a sensitivity of 56.88 nm/mmHg. This implies that the developed system has the efficiency to measure vital signs and blood pressure with cuffless, low-cost, and non-invasive.