On the monitoring of breathing volume, using textile strain gauges

Abstract

Necessity to attach measurement device to the patient mouth makes use of spirometry difficult for continuous breathing volume monitoring in non-hospital applications. There were number of attempts to replace spirometry with measurements of the trunk volume. One of the potential solutions is evaluation of the breathing volume using set of respiratory belts, placed around the chest to measure changes in trunk circumference. Such belts could be made of the highly strain—sensitive knitted resistive fabric, integrated into tight underwear, like T-shirt or compressive body. The objective of the present research was to check usability of the garment—integrated knitted strain gauges for evaluation of the breathing volume. The breathing monitoring garment have been made in a form of T-shirt with seven knitted resistive stretch sensing ribbons, sewn around the T-shirt trunk and calibrated to measure circumference. Circumferences were used to estimate trunk volume of four healthy volunteers (2 male 2 female). Alongside, volunteers breathing volume was measured using commercial spirometer. The results demonstrated that T-shirt, being calibrated irrespectively to measured individual, could evaluates breathing volume with the uncertainty of 0.6 l, given all 7 ribbons are used for calculation of volume. The individual calibration of the T-shirt for particular individual could reduce uncertainty up to 0.3 l.