Optical fibre sensors for respiration monitoring in sports and healthcare

Limweshasin, Nat (2024) Optical fibre sensors for respiration monitoring in sports and healthcare. PhD thesis, University of Nottingham.

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Abstract

The ultimate objective of this PhD thesis is the development of fibre optic sensor systems for respiratory rate and volume monitoring with the aim of contributing to the improvement of patients and athlete safety, recovery, and performance. Particularly, wearable devices which facilitate prolonged, continuous respiration measurements through user comfort as well as portability were implemented.

The respiratory volume monitoring sensor system was based on Fibre Bragg Grating (FBG) fibre optic technology. FBG-based strain sensors were integrated into a wearable sleeveless shirt to measure respiratory motion during breathing. A realistic 3D model of the human torso and anatomy of respiration biomechanics is created and used as a means of respiratory volume interpretation from sensors data. The performance of the developed respiratory volume monitoring sensor system is evaluated against a clinical spirometer through healthy volunteer studies (n = 11). The procedure involves performing deep exhalation which resembles spirometry routine: Forced Vital Capacity (FVC), and normal breathing whilst maintaining static posture. Data from 8 out of 11 volunteers with successful calibration are statically analyzed for agreements and errors using mean absolute percentage error (MAPE) and Bland-Altman analysis. The results are: Deep exhalation = 12.13% MAPE (4.87% standard deviation (SD)), 0.00 L median bias (-0.42 to 0.48 L range), 0.72 L median upper limit of agreement (LOA) (0.48 to 3.01 L range), -1.18 L median lower LOA (-2.44 to -0.45 L range); Normal breathing = 49.08% MAPE (35.18% SD), 0.08 L median bias (-0.24 to 0.86 L range), 0.64 L median upper LOA (0.06 to 1.12 L range), -0.31 L median lower LOA (-0.98 to 0.41 L range).

A respiratory rate sensor system was created by integrating FBG technology into a respirator mask. The system exploits the sensitivity of FBG to temperature to identify individual’s effort of inhalation and exhalation by measuring airflow temperature variation near the nostrils and mouth. Simultaneously, instrumentation to monitor the response of respiratory rate sensor system was also investigated. A portable, battery-powered, wireless miniature interrogator system was developed by a fellow PhD candidate and is implemented as means of acquiring FBG data in the respiratory rate sensor system to replace a relatively bulky benchtop interrogator. Healthy volunteer studies were conducted to evaluate the performance of the developed FBG-mask system (n = 10). Volunteers were asked to perform normal breathing whilst simultaneously wearing the developed FBG-mask system and a reference spirometer. Individual breaths are then identified using a peak detection algorithm. The result showed that the number of breaths detected by both devices matched exactly (100%) across every volunteer trials.

In conclusion, this PhD presented research on a novel alternative approach to respiratory rate and volume monitoring currently implemented in the field of healthcare and sports through implementation of wearable fibre optic sensors.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Korposh, Serhiy
Morgan, Stephen
Correia, Ricardo
Hayes-Gill, Barrie
Keywords: Fibre optic sensors; Wearable devices; Respiration monitoring
Subjects: R Medicine > R Medicine (General) > R855 Medical technology. Biomedical engineering. Electronics
Faculties/Schools: UK Campuses > Faculty of Engineering > Department of Electrical and Electronic Engineering
Item ID: 77449
Depositing User: Limweshasin, Nat
Date Deposited: 18 Jul 2024 04:40
Last Modified: 18 Jul 2024 04:40
URI: https://eprints.nottingham.ac.uk/id/eprint/77449

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