Unconstrained and non-invasive measurement of heart-beat and respiration periods using a phonocardiographic sensor

Abstract

With the rapid growth in the number of elderly people in the population, interest in health monitoring is increasing. Therefore the development of an unconstrained and non-invasive vital signs measurement system could be important for monitoring health status at home or in hospitals or nursing facilities. A simple system is proposed for measuring heart-beat and respiration periods for home healthcare. This was achieved with a phonocardiographic (PCG) sensor set on a water-mat or air-mat. The PCG sensor was an acceleration sensor that extracted the vibration of the mat caused by heart-beat and respiration. By calculating an autocorrelation function of the fully rectified sensor output or by local pattern matching between the rectified output and a reference signal (pre-memorised for each subject), the system measured the average and instantaneous periods of both heart-beat and respiration. Results showed that these periods were measured to a similar level of accuracy as for the electrocardiogram and thermistor respiration pickup. The comparative accuracies were within the following ranges: average heartbeat 0.19% to 0.67%, instantaneous heartbeat 0.53% to 1.15%, average respiration 0.51% to 2.17%, and instantaneous respiration 2.51% to 5.20%.

An approach to a non-contact vital sign monitoring using dual-frequency microwave radars for elderly care

“…Demiris [4] aimed to investigate elderly behavior using video and image processing while carefully addressing privacy concerns beforehand. Another study proposed an unconstrained and noninvasive vital sign measurement system for measuring heartbeat and respiration to monitor health status at home or in hospitals and nursing facilities [5].…”

Non Contact Heart Monitoring

“…A series of different laboratory solutions as well as market available monitoring systems (see web references) have been already proposed. Finally HR monitoring based on image-based methods (Da Costa, 1995;Poh, 2010;Takano and Ohta, 2007;Garbey et al, 2007), electrical impedance (Ischijima, 1993;Harland et al, 2002), acoustic and ultrasound (Tanaka et al, 2002) approaches have also been reported as valid principles for non contact heart rate monitoring.…”

Remote Sensing for Medical and Health Care Applications

“…Demiris (Demiris et al, 2009) investigated elderly behavior using a video and image processing system while carefully addressing privacy concerns. Another study proposed a non-restrictive, non-invasive vital sign measurement system for measuring heartbeat and respiration to monitor health status at home or in hospitals and nursing facilities (Tanaka et al, 2002). Systems for nursing care should meet the following requirements: (1) monitoring of activity and vital signs must not be a burden for the elderly; (2) accurately monitor changes in physical condition of the patient; and (3) when the physical condition of a patient rapidly changes, the system should promptly notify a doctor or nursing caregiver.…”