Homecare is healthcare based on the principle “outpatient before inpatient,” with the aim of moving at least some care-delivery to the home. But reliable determination of vital signs at home requires new, smart sensors, which can be used by the patients themselves. We present a novel pulse oximetry sensor worn in the ear channel. It was previously shown that measurement of heart rate, arterial oxygen saturation and related respiratory information can be performed with reliable accuracy under laboratory conditions. The present study explores the clinical feasibility of the sensor system for cardiovascular monitoring during sleep, with the aim to diagnose sleep apnea. For this, human trials were performed in a sleep laboratory including patients with a clinical suspicion of sleep apnea. Besides a general analysis of the sensor’s signal quality during sleep, the evaluation focuses on heart rate dynamics and time-variant oxygen saturation. In addition, several methods to derive respiration rate from photoplethysmographic signals are examined and discussed. Results from the in-ear sensor are compared with standard polysomnography monitoring and demonstrate that this novel system allows long-term nocturnal measurement of heart rate, oxygen saturation and respiratory rate with sufficient accuracy.
See complete bios of the authors in the full version of this article.
Mr. Venema holds a Dipl.-Ing. degree in Electrical Engineering from RWTH Aachen University, Aachen, Germany. Currently, he is pursuing a Dr.-Ing. (Ph.D.) degree at the Philips Chair of Medical Information Technology, RWTH Aachen University, where he is also working as a Research Assistant.
Mr. Schiefer is currently working as Senior Physician in the Department of Neurology, RWTH Aachen University Hospital, Aachen, Germany. His main concern of research includes sleep disorders, neurodegenerative disorders and media-assisted interactive clinical teaching.
Mr. Blazek is with the Philips Chair of Medical Information Technology, RWTH Aachen University. His current research interests include optoelectronics in medicine, biomedical sensors, functional optical imaging techniques, and tissue optics.
Mr. Blanik is pursuing a Dr.-Ing. (Ph.D.) degree at the Philips Chair of Medical Information Technology, RWTH Aachen University, where he is also working as a Research Assistant. His research interests include research of photontissue interaction with Monte-Carlo Simulation and Photoplethysmographic Imaging.
Mr. Leonhardt was appointed Full Professor and Head of the Philips endowed Chair of Medical Information Technology at RWTH Aachen University, Germany, in 2003. His research interests include physiological measurement techniques, personal health care systems and feedback control systems in medicine.
This article appeared in the 2013 issue of IEEE Journal of Translational Engineering in Health and Medicine.
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