title: A sensor for monitoring pulse rate, respiration rhythm, and body movement in bed.
abstract: A non-constraint cardiac vibration, respiration, and body movement monitoring system has been developed. The sensor system is designed to be easily installable under an existing bed mattress. The sensor consists of a 40-kHz ultrasound transmitter and receiver pair. The transmitted ultrasound is reflected on the mattress' undersurface, and the amplitude of the received ultrasonic wave is modulated by the shape of the mattress, and parameters such as respiration, cardiac vibration, and movement. The physiological parameters can be extracted from the reflected ultrasound by an envelope detection circuit. To confirm the accuracy of the developed system, measurements were performed on 6 normal male subjects aged 25.0 ± 6.7 years, using 2 pocket spring coil mattresses and a polyurethane foam mattress. The results revealed that the physiological parameters were monitored with an 84.2% average accuracy for all mattresses when the subjects lay on the beds in the supine, lateral, and prone positions.
authors.affiliation: Department of Health Science, Faculty of Applied Information Science, Hiroshima Institute of Technology, 2-1-1 Miyake, Saeki, Hiroshima 731-5193, Japan. bb08010@cc.it-hiroshima.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamana
authors.forename: Sosuke
authors.initials: S
authors.lastname: Tsukamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Mukai
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Maki
authors.forename: Hidekuni
authors.initials: H
authors.lastname: Ogawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Yonezawa
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D001513:Beds; D004562:Electrocardiography / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009991:Oscillometry / Q000295:instrumentation*; D056152:Respiratory Rate / Q000502:physiology*; D014159:Transducers