Development and Feasibility Test of a Capacitive Belt Sensor for Noninvasive Respiration Monitoring in Different Postures

Abstract The purpose of this study was to develop an easy-wear capacitive belt sensor, examine its performance, and test the feasibility for differentiating posture-dependent respiration changes, consequently for monitoring of variable respiration patterns during real life activities. Seven healthy adult males participated in this study. Respiration (at rest) data were collected simultaneously from capacitive belt sensor and commercial sensor (BIOPAC MP150) for 3 minutes in each of the 6 different static postures representative of real-life activity postures: supine with neutral head position, standing, sitting, side lying, supine with 45︒ cervical flexion, and supine with 45︒ cervical extension. From the collected data, 3 respiratory parameters including total respiration count (RC), peak to peak interval time (PPI), and respiratory rate (RR) were analyzed. Correlation analysis was conducted for all three of the parameters collected by the two sensors. The highest PPI values were found in cervical extension supine posture and the lowest in side lying. RC and PPI patterns were inversely related. The results of RR showed to have exactly the same pattern with RC; the highest rate was during standing and the lowest in cervical extension supine. The RRs detected by our sensor were within the normal range, confirming the performance and feasibility of our sensor. As our sensor was able to detect posture-dependent respiration pattern differences, potential application in sleep apnea monitoring, respiratory disease prevention, and early detection of diagnostic symptoms has been confirmed.