Optical fibre sensor for simultaneous measurement of capillary refill time and contact pressure

Liu, Chong; Correia, Ricardo; Ballaji, Hattan; Korposh, Serhiy; Hayes‐gill, Barrie; Morgan, Stephen

Abstract

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The widely applied capillary refill time (CRT) measurement is currently performed by manually applying pressure and using a stopwatch to record the time taken for the skin to recover its normal colour after a blanching pressure is applied. This method is highly subjective and observer‐dependent. This paper presents a new, integrated optical sensor probe, combining monitoring of the capillary refilling process with the blanching pressure applied. The sensor consists of an optical fibre‐based reflectance photoplethysmography (PPG) sensor to measure the reflected light signal, as well as a fibre Bragg grating (FBG) to measure the applied blanching pressure and to indicate the time when pressure is released. This sensor was applied to calculate the CRT (1.38 ± 0.66 s) of 10 healthy adult volunteers with (55.2 ± 21.8 kPa) blanching pressures. The form of the capillary refilling data was investigated by fitting using an exponential regression model (R2 > 0.96). The integrated probe has the potential to improve the reliability of CRT measurements by standardising the optimum duration and magnitude of the pressure.

Citation

Liu, C., Correia, R., Ballaji, H., Korposh, S., Hayes‐gill, B., & Morgan, S. (2020). Optical fibre sensor for simultaneous measurement of capillary refill time and contact pressure. Sensors, 20(5), Article 1388. https://doi.org/10.3390/s20051388

• Journal Article Type: Article
• Acceptance Date: Mar 1, 2020
• Online Publication Date: Mar 3, 2020
• Publication Date: Mar 3, 2020
• Deposit Date: Mar 12, 2020
• Publicly Available Date: Mar 12, 2020
• Journal: Sensors
• Print ISSN: 1424-8220
• Electronic ISSN: 1424-8220
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 20
• Issue: 5
• Article Number: 1388
• DOI: https://doi.org/10.3390/s20051388
• Keywords: capillary refill time; plastic optical fibre; photoplethysmography; fibre bragg grating; contact pressure
• Public URL: https://nottingham-repository.worktribe.com/output/4100800
• Publisher URL: https://www.mdpi.com/1424-8220/20/5/1388