title: Evaluating Innovative In-Ear Pulse Oximetry for Unobtrusive Cardiovascular and Pulmonary Monitoring During Sleep.
abstract: 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.
authors.affiliation: RWTH Aachen University Philips Chair for Medical Information Technology (MedIT) Aachen Germany 52074.
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Venema
authors.affiliation: RWTH Aachen University Hospital Department of Neurology Aachen Germany 52074.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schiefer
authors.affiliation: RWTH Aachen University Philips Chair for Medical Information Technology (MedIT) Aachen Germany 52074.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Blazek
authors.affiliation: RWTH Aachen University Philips Chair for Medical Information Technology (MedIT) Aachen Germany 52074.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Blanik
authors.affiliation: RWTH Aachen University Philips Chair for Medical Information Technology (MedIT) Aachen Germany 52074.
authors.forename: Steffen
authors.initials: S
authors.lastname: Leonhardt
keywords: Photoplethysmography (PPG); blood volume dynamics; oxygen saturation; pulse oximetry; sleep apnea