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El Arja S, Jayarathna T, Naik G, Breen P, Gargiulo G. Characterisation of Morphic Sensors for Body Volume and Shape Applications. SENSORS (BASEL, SWITZERLAND) 2019; 20:E90. [PMID: 31877893 PMCID: PMC6983190 DOI: 10.3390/s20010090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 02/01/2023]
Abstract
Stretchable conductive materials are originally conceived as radio frequency (RF) and electromagnetic interference (EMI) shielding materials, and, under stretch, they generally function as distributed strain-gauges. These commercially available conductive elastomers have found their space in low power health monitoring systems, for example, to monitor respiratory and cardiac functions. Conductive elastomers do not behave linearly due to material constraints; hence, when used as a sensor, a full characterisation to identify ideal operating ranges are required. In this paper, we studied how the continuous stretch cycles affected the material electrical and physical properties in different embodiment impressed by bodily volume change. We simulated the stretch associated with breathing using a bespoke stress rig to ensure reproducibility of results. The stretch rig is capable of providing constant sinusoidal waves in the physiological ranges of extension and frequency. The material performances is evaluated assessing the total harmonic distortion (THD), signal-to-noise ratio (SNR), correlation coefficient, peak to peak (P-P) amplitude, accuracy, repeatability, hysteresis, delay, and washability. The results showed that, among the three controlled variables, stretch length, stretch frequency and fabric width, the most significant factor to the signal quality is the stretch length. The ideal working region is within 2% of the original length. The material cut in strips of > 3 show more reliable to handle a variety of stretch parameter without losing its internal characteristics and electrical properties.
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Affiliation(s)
- Sami El Arja
- School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, NSW 2751, Australia;
| | - Titus Jayarathna
- MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Milperra, NSW 2560, Australia; (G.N.); (P.B.)
| | - Ganesh Naik
- MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Milperra, NSW 2560, Australia; (G.N.); (P.B.)
| | - Paul Breen
- MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Milperra, NSW 2560, Australia; (G.N.); (P.B.)
- Translational Health Research Institute, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Gaetano Gargiulo
- School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, NSW 2751, Australia;
- MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Milperra, NSW 2560, Australia; (G.N.); (P.B.)
- Translational Health Research Institute, Western Sydney University, Campbelltown, NSW 2560, Australia
- School of Psychiatry and Ingham Institute of Applied Medical Research, University of New South Wales, Liverpool, NSW 2052, Australia
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Gargiulo GD, O'Loughlin A, Breen PP. Electro-resistive bands for non-invasive cardiac and respiration monitoring, a feasibility study. Physiol Meas 2015; 36:N35-49. [PMID: 25585657 DOI: 10.1088/0967-3334/36/2/n35] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Continuous unobtrusive monitoring of tidal volume, particularly for critical care patients (i.e. neonates and patients in intensive care) during sleep studies and during daily activities, is still an unresolved monitoring need. Also a successful monitoring solution is yet to be proposed for continuous non-invasive cardiac stroke volume monitoring that is a novel clinical need.In this paper we present the feasibility study for a wearable, non-invasive, non-contact and unobtrusive sensor (embedded in a standard T-shirt) based on four electro-resistive bands that simultaneously monitors tidal volume and cardiac stroke volume changes. This low power sensor system (requires only 100 mW and accepts a wide power supply range up to ±18 V); thus the sensor can be easily embedded in existing wearable solutions (i.e. Holter monitors). Moreover, being contactless, it can be worn over bandages or electrodes, and as it does not rely over the integrity of the garment to work, it allows practitioners to perform procedures during monitoring. For this preliminary evaluation, one subject has worn the sensor over the period of 24 h (removing it only to shower); the accuracy of the tidal volume tested against a portable spirometer reported a precision of ±10% also during physical activity; accuracy tests for cardiac output (as it may require invasive procedure) have not been carried out in this preliminary trial.
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Bellani G, Patroniti N, Pesenti A. Measurement of Functional Residual Capacity during Mechanical Ventilation. Intensive Care Med 2010. [DOI: 10.1007/978-1-4419-5562-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kondo T, Minocchieri S, Baldwin DN, Nelle M, Frey U. Noninvasive monitoring of chest wall movement in infants using laser. Pediatr Pulmonol 2006; 41:985-92. [PMID: 16868962 DOI: 10.1002/ppul.20482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Traditionally, non-invasive monitoring of tidal volume in infants has been performed using impedance plethysmography analyzed using a one or two compartment model. We developed a new laser system for use in infants, which measures antero-posterior movement of the chest wall during quiet sleep. In 24 unsedated or sedated infants (11 healthy, 13 with respiratory disease), we examined whether the analysis of thoracoabdominal movement based on a three compartment model could more accurately estimate tidal volume in comparison to V(T) measured at the mouth. Using five laser signals, chest wall movements were measured at the right and left, upper and lower ribcage and the abdomen. Within the tidal volume range from 4.6 to 135.7 ml, a three compartment model showed good short term repeatability and the best agreement with tidal volume measured at mouth (r(2) = 0.86) compared to that of a single compartment model (r(2) = 0.62, P < 0.0001) and a two compartment model (r(2) = 0.82, P < 0.01), particularly in the presence of respiratory disease. Three compartment modeling of a 5 laser thoracoabdominal monitoring permits more accurate estimates of tidal volume in infants and potentially of regional differences of chest wall displacement in future studies.
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Affiliation(s)
- Tsutomu Kondo
- Pediatric Respiratory Medicine, University Children's Hospital of Berne, Berne, Switzerland.
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