A Textile Sleeve for Monitoring Oxygen Saturation Using Multichannel Optical Fibre Photoplethysmography

Ballaji, Hattan K.; Correia, Ricardo; Korposh, Serhiy; Hayes-Gill, Barrie R.; Hernandez, Francisco U.; Salisbury, Byron; Morgan, Stephen P.

Abstract

Textile-based systems are an attractive prospect for wearable technology as they can provide monitoring of key physiological parameters in a comfortable and unobtrusive form. A novel system based on multichannel optical fibre sensor probes integrated into a textile sleeve is described. The system measures the photoplethysmogram (PPG) at two wavelengths (660 and 830 nm), which is then used to calculate oxygen saturation (SpO2). In order to achieve reliable measurement without adjusting the position of the garment, four plastic optical fibre (POF) probes are utilised to increase the likelihood that a high-quality PPG is obtained due to at least one of the probes being positioned over a blood vessel. Each probe transmits and receives light into the skin to measure the PPG and SpO2. All POFs are integrated in a stretchable textile sleeve with a circumference of 15 cm to keep the sensor in contact with the subject's wrist and to minimise motion artefacts. Tests on healthy volunteers show that the multichannel PPG sensor faithfully provides an SpO2 reading in at least one of the four sensor channels in all cases with no need for adjusting the position of the sleeve. This could not be achieved using a single sensor alone. The multichannel sensor is used to monitor the SpO2 of 10 participants with an average wrist circumference of 16.0 ± 0.6 cm. Comparing the developed sensor's SpO2 readings to a reference commercial oximeter (reflectance Masimo Radical-7) illustrates that the mean difference between the two sensors' readings is -0.03%, the upper limit of agreement (LOA) is 0.52% and the lower LOA is -0.58%. This multichannel sensor has the potential to achieve reliable, unobtrusive and comfortable textile-based monitoring of both heart rate and SpO2 during everyday life.

Citation

Ballaji, H. K., Correia, R., Korposh, S., Hayes-Gill, B. R., Hernandez, F. U., Salisbury, B., & Morgan, S. P. (2020). A Textile Sleeve for Monitoring Oxygen Saturation Using Multichannel Optical Fibre Photoplethysmography. Sensors, 20(22), Article 6568. https://doi.org/10.3390/s20226568

• Journal Article Type: Article
• Acceptance Date: Nov 15, 2020
• Online Publication Date: Nov 17, 2020
• Publication Date: Nov 17, 2020
• Deposit Date: Nov 20, 2020
• Publicly Available Date: Nov 20, 2020
• Journal: Sensors (Basel, Switzerland)
• Electronic ISSN: 1424-8220
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 20
• Issue: 22
• Article Number: 6568
• DOI: https://doi.org/10.3390/s20226568
• Keywords: Electrical and Electronic Engineering; Analytical Chemistry; Atomic and Molecular Physics, and Optics; Biochemistry
• Public URL: https://nottingham-repository.worktribe.com/output/5055318
• Publisher URL: https://www.mdpi.com/1424-8220/20/22/6568