Simultaneous measurement of respiratory behavior using three different sensors: Pressure transducer-based, belt-type, and thermistor-based methods

Humans perform multiple short-term rapid inspirations (MSTRIs) in one respiration to facilitate odor perception in daily life. This study first characterized each of the three different respiration sensors (pressure transducer-based, belt-type, and thermistor-based methods) by simultaneously measuring normal respiration (NR). We then examined which of the three respiration sensors could detect MSTRI. A participant was instructed to perform two MSTRIs in each inspiratory phase. An original detection algorithm was applied to analog-to-digital converted respiratory signals. The pressure transducer-based respiratory sensor had the highest detection rate of NRs, followed by the thermistor-based and belt-type respiratory sensors. In addition, each respiratory sensor was characterized by respiratory rate, latency (inspiratory and expiratory phases), and duration (single respiration, inspiratory phase, and expiratory phase), but it was difficult to explain the differences among sensors only in terms of time constant. MSTRIs could only be detected by the pressure transducer-based respiratory sensor. These results suggest that the pressure transducer-based respiratory sensor is the most suitable to measure respiratory behavior (i.e., NR and MSTRIs) among the three different respiratory sensors.