{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T13:37:26Z","timestamp":1774273046103,"version":"3.50.1"},"reference-count":48,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2018,8,9]],"date-time":"2018-08-09T00:00:00Z","timestamp":1533772800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["228013"],"award-info":[{"award-number":["228013"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper introduces a novel respiratory detection system based on diaphragm wall motion tracking using an embedded ultrasound sensory system. We assess the utility and accuracy of this method in evaluating the function of the diaphragm and its contribution to respiratory workload. The developed system is able to monitor the diaphragm wall activity when the sensor is placed in the zone of apposition (ZOA). This system allows for direct measurements with only one ultrasound PZT5 piezo transducer. The system generates pulsed ultrasound waves at 2.2 MHz and amplifies reflected echoes. An added benefit of this system is that due to its design, the respiratory signal is less subject to motion artefacts. Promising results were obtained from six subjects performing six tests per subject with an average respiration detection sensitivity and specificity of 84% and 93%, respectively. Measurements were compared to a gold standard commercial spirometer. In this study, we also compared our measurements to other conventional methods such as inertial and photoplethysmography (PPG) sensors.<\/jats:p>","DOI":"10.3390\/s18082617","type":"journal-article","created":{"date-parts":[[2018,8,9]],"date-time":"2018-08-09T10:36:31Z","timestamp":1533810991000},"page":"2617","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Ultrasound Sensors for Diaphragm Motion Tracking: An Application in Non-Invasive Respiratory Monitoring"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4239-9262","authenticated-orcid":false,"given":"Amirhossein","family":"Shahshahani","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, McGill university, Montreal, QC H3A 0E9, Canada"}]},{"given":"Carl","family":"Laverdiere","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, McGill University, Montreal, QC H3A 0E9, Canada"}]},{"given":"Sharmistha","family":"Bhadra","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, McGill university, Montreal, QC H3A 0E9, Canada"}]},{"given":"Zeljko","family":"Zilic","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, McGill university, Montreal, QC H3A 0E9, Canada"}]}],"member":"1968","published-online":{"date-parts":[[2018,8,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"796","DOI":"10.1007\/s00134-012-2547-7","article-title":"Diaphragm ultrasonography to estimate the work of breathing during non-invasive ventilation","volume":"38","author":"Vivier","year":"2012","journal-title":"Intensive Care Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"79","DOI":"10.21037\/atm.2017.01.68","article-title":"Diaphragmatic ultrasound as a monitoring tool in the intensive care unit","volume":"5","author":"Sigala","year":"2017","journal-title":"Ann. Transl. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1164\/rccm.2206020","article-title":"Disorders of the respiratory muscles","volume":"168","author":"Laghi","year":"2003","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_4","first-page":"509","article-title":"Sleep disordered breathing in isolated unilateral and bilateral diaphragmatic dysfunction","volume":"10","author":"Khan","year":"2014","journal-title":"J. Clin. Sleep Med. JCSM Off. Publ. Am. Acad. Sleep Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1109\/TBME.2015.2466633","article-title":"Evaluation of Ultrasound-Based Sensor to Monitor Respiratory and Nonrespiratory Movement and Timing in Infants","volume":"63","author":"Heldt","year":"2016","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1186\/s13054-015-0894-9","article-title":"Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: A pilot clinical study","volume":"19","author":"Umbrello","year":"2015","journal-title":"Crit. Care"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1002\/cphy.c110057","article-title":"Central sleep apnoea","volume":"3","author":"Javaheri","year":"2013","journal-title":"Comp. Physiol."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Sinharay, A., Rakshit, R., Khasnobish, A., Chakravarty, T., Ghosh, D., and Pal, A. (2017). The Ultrasonic Directional Tidal Breathing Pattern Sensor: Equitable Design Realization Based on Phase Information. Sensors, 17.","DOI":"10.3390\/s17081853"},{"key":"ref_9","unstructured":"Araujo, G., Freire, R., Silva, J., Oliveira, A., and Jaguaribe, E. (2004, January 18\u201320). Breathing flow measurement with constant temperature hot-wire anemometer for forced oscillations technique. Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.04CH37510), Como, Italy."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Bai, Y.W., Li, W.T., and Chen, Y.W. (2010, January 1\u20133). Design and implementation of an embedded monitor system for detection of a patient\u2019s breath by double webcams. Proceedings of the 12th IEEE International Conference on e-Health Networking, Applications and Services, Lyon, France.","DOI":"10.1109\/HEALTH.2010.5556526"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Bu, N., Ueno, N., and Fukuda, O. (2007, January 22\u201326). Monitoring of Respiration and Heartbeat during Sleep using a Flexible Piezoelectric Film Sensor and Empirical Mode Decomposition. Proceedings of the 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Lyon, France.","DOI":"10.1109\/IEMBS.2007.4352551"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Loriga, G., Taccini, N., Rossi, D.D., and Paradiso, R. (2005, January 1\u20134). Textile Sensing Interfaces for Cardiopulmonary Signs Monitoring. Proceedings of the 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, Shanghai, China.","DOI":"10.1109\/IEMBS.2005.1616209"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"13088","DOI":"10.3390\/s140713088","article-title":"An optical fibre-based sensor for respiratory monitoring","volume":"14","author":"Krehel","year":"2014","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"204","DOI":"10.3390\/jfb6020204","article-title":"Medical smart textiles based on fibre optic technology: An overview","volume":"6","author":"Massaroni","year":"2015","journal-title":"J. Funct. Biomater."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Jeong, J., Jang, Y., Lee, I., Shin, S., and Kim, S. (2009, January 7\u201312). Wearable respiratory rate monitoring using piezo-resistive fabric sensor. Proceedings of the World Congress on Medical Physics and Biomedical Engineering, Munich, Germany.","DOI":"10.1007\/978-3-642-03904-1_78"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1532","DOI":"10.1109\/JBHI.2015.2445783","article-title":"Design and evaluation of an intelligent remote tidal volume variability monitoring system in e-health applications","volume":"19","author":"Fekr","year":"2015","journal-title":"IEEE J. Biomed. Health Inf."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"15371","DOI":"10.3390\/s140815371","article-title":"An Ultrasonic Contactless Sensor for Breathing Monitoring","volume":"14","author":"Arlotto","year":"2014","journal-title":"Sensors"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"740","DOI":"10.1542\/peds.2011-0271","article-title":"Pulse oximetry in pediatric practice","volume":"128","author":"Fouzas","year":"2011","journal-title":"Pediatrics"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1016\/j.clp.2012.06.012","article-title":"Noninvasive monitoring by photoplethysmography","volume":"39","author":"Sahni","year":"2012","journal-title":"Clinics Perinatol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1097\/ALN.0b013e3181895f9f","article-title":"Poor agreement between respiratory variations in pulse oximetry photoplethysmographic waveform amplitude and pulse pressure in intensive care unit patients","volume":"109","author":"Landsverk","year":"2008","journal-title":"J. Am. Soc. Anesthesiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1088\/1361-6579\/aa670e","article-title":"Extraction of respiratory signals from the electrocardiogram and photoplethysmogram: Technical and physiological determinants","volume":"38","author":"Charlton","year":"2017","journal-title":"Physiol. Meas."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1213\/01.ane.0000222477.67637.17","article-title":"What is the best site for measuring the effect of ventilation on the pulse oximeter waveform?","volume":"103","author":"Shelley","year":"2006","journal-title":"Anesthesia Analgesia"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1136\/bjsm.25.3.162","article-title":"Accuracy of pulse oximeters in estimating heart rate at rest and during exercise","volume":"25","author":"Iyriboz","year":"1991","journal-title":"Br. J. Sports Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/RBME.2017.2763681","article-title":"Breathing rate estimation from the electrocardiogram and photoplethysmogram: A review","volume":"11","author":"Charlton","year":"2017","journal-title":"IEEE Rev. Biomed. Eng."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3109\/03091902.2011.638965","article-title":"Photoplethysmographic derivation of respiratory rate: A review of relevant physiology","volume":"36","author":"Meredith","year":"2012","journal-title":"J. Med. Eng. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1186\/cc11146","article-title":"Clinical review: Respiratory monitoring in the ICU-a consensus of 16","volume":"16","author":"Brochard","year":"2012","journal-title":"Crit. Care"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1002\/mrm.1910380118","article-title":"Amplitude demodulation of the electrocardiogram signal (ECG) for respiration monitoring and compensation during MR examinations","volume":"38","author":"Felblinger","year":"1997","journal-title":"Magn. Reson. Med."},{"key":"ref_28","first-page":"113","article-title":"Derivation of respiratory signals from multi-lead ECGs","volume":"12","author":"Moody","year":"1985","journal-title":"Comput. Cardiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"16372","DOI":"10.3390\/s150716372","article-title":"Instantaneous respiratory estimation from thoracic impedance by empirical mode decomposition","volume":"15","author":"Wang","year":"2015","journal-title":"Sensors"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TSMCC.2009.2032660","article-title":"A Survey on Wearable Sensor-Based Systems for Health Monitoring and Prognosis","volume":"40","author":"Pantelopoulos","year":"2010","journal-title":"IEEE Trans. Syst. Man Cybern. Part C Appl. Rev."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e330","DOI":"10.1097\/CCM.0000000000001110","article-title":"Point-of-Care Ultrasound","volume":"43","author":"Sweeney","year":"2015","journal-title":"Crit. Care Med."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1097\/CCM.0000000000001657","article-title":"Mechanical ventilation and diaphragmatic atrophy in critically ill patients: An ultrasound study","volume":"44","author":"Zambon","year":"2016","journal-title":"Crit. Care Med."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Shahshahani, A., Bhadra, S., and Zilic, Z. (2018, January 27\u201330). A Continuous Respiratory Monitoring System Using Ultrasound Piezo Transducer. Proceedings of the 2018 IEEE International Symposium on Circuits and Systems (ISCAS), Florence, Italy.","DOI":"10.1109\/ISCAS.2018.8351359"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"648","DOI":"10.1016\/S0002-8703(96)90251-3","article-title":"Myocardial wall velocity assessment by pulsed Doppler tissue imaging: Characteristic findings in normal subjects","volume":"132","author":"Garcia","year":"1996","journal-title":"Am. Heart J."},{"key":"ref_35","unstructured":"Tole, N.M. (2005). Basic Physics of Ultrasonic Imaging, The World Health Organization Press."},{"key":"ref_36","unstructured":"Shung, K. (1998). Diagnostic Ultrasound: Imaging and Blood Flow Measurements, Wiley."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/S0360-3016(01)01453-5","article-title":"Organ motion and its management","volume":"50","author":"Langen","year":"2001","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Shahshahani, A., Nafchi, D.R., and Zilic, Z. (2017, January 28\u201331). Ultrasound sensors and its application in human heart rate monitoring. Proceedings of the 2017 IEEE International Symposium on Circuits and Systems (ISCAS), Baltimore, MD, USA.","DOI":"10.1109\/ISCAS.2017.8050899"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/S0272-5231(21)00498-6","article-title":"Functional anatomy of the respiratory muscles","volume":"9","author":"De","year":"1988","journal-title":"Clin. Chest Med."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1002\/mus.23671","article-title":"Neuromuscular ultrasound for evaluation of the diaphragm","volume":"47","author":"Sarwal","year":"2013","journal-title":"Muscle Nerve"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"634","DOI":"10.1136\/thx.49.7.634","article-title":"Dynamic changes in the zone of apposition and diaphragm length during maximal respiratory efforts","volume":"49","author":"McKenzie","year":"1994","journal-title":"Thorax"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1560","DOI":"10.1152\/jappl.1989.67.4.1560","article-title":"Diaphragmatic thickness-lung volume relationship in vivo","volume":"67","author":"Wait","year":"1989","journal-title":"J. Appl. Physiol."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Zambon, M., Cabrini, L., and Zangrillo, A. (2013). Diaphragmatic ultrasound in critically ill patients. Annual Update in Intensive Care and Emergency Medicine, Springer.","DOI":"10.1007\/978-3-642-35109-9_35"},{"key":"ref_44","unstructured":"(2008). Guidance for Industry and FDA Staff Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers, Food and Drug Administration."},{"key":"ref_45","unstructured":"OMSignal Validation of Breathing Rate Algorithm During Running."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1148\/radiology.209.2.9807578","article-title":"Diaphragmatic and cardiac motion during suspended breathing: preliminary experience and implications for breath-hold MR imaging","volume":"209","author":"Holland","year":"1998","journal-title":"Radiology"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1148\/radiol.2502071998","article-title":"Motion in cardiovascular MR imaging","volume":"250","author":"Scott","year":"2009","journal-title":"Radiology"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Esquinas, A.M. (2016). Monitoring Patients During Noninvasive Ventilation: The Clinical Point of View. Noninvasive Mechanical Ventilation: Theory, Equipment, and Clinical Applications, Springer.","DOI":"10.1007\/978-3-319-21653-9"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/8\/2617\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:17:46Z","timestamp":1760195866000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/8\/2617"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,8,9]]},"references-count":48,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2018,8]]}},"alternative-id":["s18082617"],"URL":"https:\/\/doi.org\/10.3390\/s18082617","relation":{"has-preprint":[{"id-type":"doi","id":"10.20944\/preprints201807.0026.v1","asserted-by":"object"}]},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,8,9]]}}}