Unconstrained and non-invasive measurement of heart-beat and respiration periods using a phonocardiographic sensor.
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%.
Tanaka
S
S
Faculty of Engineering, Yamaguchi University, Japan.
Matsumoto
Y
Y
Wakimoto
K
K
D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D016022:Case-Control Studies; D006339:Heart Rate; D006701:Home Nursing; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D010701:Phonocardiography / Q000295:instrumentation; D012119:Respiration