Publications

@article{Limweshasin2024-mu,

title = {Respiratory rate monitoring via a Fibre Bragg Grating-embedded  respirator mask with a wearable miniature interrogator},

author = {Nat Limweshasin and Itzel Avila Castro and Serhiy Korposh and Stephen P Morgan and Barrie R Hayes-Gill and Mark A Faghy and Ricardo Correia},

doi = {10.3390/s24237476},

year  = {2024},

date = {2024-11-01},

urldate = {2024-11-01},

journal = {Sensors (Basel)},

volume = {24},

number = {23},

pages = {7476},

publisher = {MDPI AG},

abstract = {A respiration rate (RR) monitoring system was created by 

 integrating a Fibre Bragg Grating (FBG) optical fibre sensor 

 into a respirator mask. The system exploits the sensitivity of 

 an FBG to temperature to identify an individual\'s RR by 

 measuring airflow temperature variation near the nostrils and 

 mouth. To monitor the FBG response, a portable, battery-powered, 

 wireless miniature interrogator system was developed to replace 

 a relatively bulky benchtop interrogator used in previous 

 studies. A healthy volunteer study was conducted to evaluate the 

 performance of the developed system (10 healthy volunteers). 

 Volunteers were asked to perform normal breathing whilst 

 simultaneously wearing the system and a reference spirometer for 

 120 s. 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 

 all volunteer trials.},

keywords = {ambulatory, fibre bragg grating, respiration rate, temperature, wearable},

pubstate = {published},

tppubtype = {article}

}

@article{Bradbury2022-ih,

title = {Fibre Bragg grating based interface pressure sensor for 

 compression therapy},

author = {James A Bradbury and Qimei Zhang and Francisco U Hernandez Ledezma and Ricardo Correia and Serhiy Korposh and Barrie R Hayes-Gill and Ferdinand Tamou\'{e} and Alison Parnham and Simon A McMaster and Stephen P Morgan},

year  = {2022},

date = {2022-02-01},

journal = {Sensors (Basel)},

volume = {22},

number = {5},

pages = {1798},

publisher = {MDPI AG},

abstract = {Compression therapy is widely used as the gold standard for 

 management of chronic venous insufficiency and venous leg 

 ulcers, and the amount of pressure applied during the 

 compression therapy is crucial in supporting healing. A fibre 

 optic pressure sensor using Fibre Bragg Gratings (FBGs) is 

 developed in this paper to measure sub-bandage pressure whilst 

 removing cross-sensitivity due to strain in the fibre and 

 temperature. The interface pressure is measured by an FBG 

 encapsulated in a polymer and housed in a textile to minimise 

 discomfort for the patient. The repeatability of a manual 

 fabrication process is investigated by fabricating and 

 calibrating ten sensors. A customized calibration setup 

 consisting of a programmable translation stage and a weighing 

 scale gives sensitivities in the range 0.4-1.5 pm/mmHg (2.6-11.3 

 pm/kPa). An alternative calibration method using a rigid plastic 

 cylinder and a blood pressure cuff is also demonstrated. 

 Investigations are performed with the sensor under a compression 

 bandage on a phantom leg to test the response of the sensor to 

 changing pressures in static situations. Measurements are taken 

 on a human subject to demonstrate changes in interface pressure 

 under a compression bandage during motion to mimic a clinical 

 application. These results are compared to the current gold 

 standard medical sensor using a Bland-Altman analysis, with a 

 median bias ranging from -4.6 to -20.4 mmHg, upper limit of 

 agreement (LOA) from -13.5 to 2.7 mmHg and lower LOA from -32.4 

 to -7.7 mmHg. The sensor has the potential to be used as a 

 training tool for nurses and can be left in situ to monitor 

 bandage pressure during compression therapy.},

keywords = {compression therapy, fibre bragg grating, optical fibre sensor, sub-bandage pressure sensor, venous leg ulcer},

pubstate = {published},

tppubtype = {article}

}

@article{Liu2020-xk,

title = {Optical fibre sensor for simultaneous measurement of capillary 

 refill time and contact pressure},

author = {Chong Liu and Ricardo Correia and Hattan Ballaji and Serhiy Korposh and Barrie Hayes-Gill and Stephen Morgan},

year  = {2020},

date = {2020-03-01},

journal = {Sensors (Basel)},

volume = {20},

number = {5},

pages = {1388},

publisher = {MDPI AG},

abstract = {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.},

keywords = {Capillary refill time, contact pressure, fibre bragg grating, photoplethysmography, plastic optical fibre},

pubstate = {published},

tppubtype = {article}

}