Optical-Based Sensor Prototype for Continuous Monitoring of the Blood Pressure

In this paper, we report a prototype ring sensor device for continuous measurement of blood pressure with the use of our, previously developed, heart-rate monitoring ring device. An experiment is described where the heart-rate device provides the voltage output of the heart using the transmission photoplethysmography (PPG) method and predicts the blood pressure’s value to ±5% of its true value. We report a novel potential non-invasive, low cost, continuous heart rate, and blood pressure monitoring device that uses transmission PPG instead of the traditional cuff method to observe the changes in volume of the pressure through the arteries of the finger. The continuous samples are averaged out constantly. We employed the PPG technique to optically determine the blood volume changes in the arteries of the finger. A Pearson’s product moment correlation coefficient proved an r value of 0.86 showing strong linear correlation between the average voltage of the heart rate and the corresponding blood pressure. The proposed blood pressure ring sensor device was tested and benchmarked (against Nonin 2120 benchmark blood pressure device) four participants for a continuous period of 4 h, where the average mean arterial pressure (MAP) (using Nonin 2120) for 4 h was at 98.92 mmHg and the average predicted MAP was at 92.8 mmHg, which demonstrates an accuracy of 93.8%.The average real systolic pressure (using Nonin 2120) was at 144.25 mmHg and the predicted average systolic pressure was at 132.77 mmHg which shows an accuracy of 92%. The average real diastolic pressure (using Nonin 2120) was at 76.25 mmHg and the predicted diastolic pressure was 72.7 mmHg, showing an accuracy of 95.5%.