Comparison of impedance and inductance ventilation sensors on adults during breathing, motion, and simulated airway obstruction

Abstract

The goal of this study was to compare the relative performance of two noninvasive ventilation sensing technologies on adults during artifacts. We recorded changes in transthoracic impedance and cross-sectional area of the abdomen (abd) and rib cage (rc) using impedance pneumography (IP) and respiratory inductance plethysmography (RIP) on ten adult subjects during natural breathing, motion artifact, simulated airway obstruction, yawning, snoring, apnea, and coughing. We used a pneumotachometer to measure air flow and tidal volume as the standard. We calibrated all sensors during natural breathing, and performed measurements during all maneuvers without changing the calibration parameters. No sensor provided the most-accurate measure of tidal volume for all maneuvers. Overall, the combination of inductance sensors [RIP(sum)] calibrated during an isovolume maneuver had a bias (weighted mean difference) as low or lower than all individual sensors and all combinations of sensors. The IP(rc) sensor had a bias as low or lower than any individual sensor. The cross-correlation coefficient between sensors was high during natural breathing, but decreased during artifacts. The cross correlation between sensor pairs was lower during artifacts without breathing than it was during maneuvers with breathing for four different sensor combinations. We tested a simple breath-detection algorithm on all sensors and found that RIP(sum) resulted in the fewest number of false breath detections, with sensitivity of 90.8% and positive predictivity of 93.6%.

Adaptive motion artefact reduction in respiration and ECG signals for wearable healthcare monitoring systems

“…It has been demonstrated that for RIP, the sum of RC and AB outperforms individual use of RC or AB for breath detection [5]. Therefore, in our study, RC and AB displacements were linearly combined with unit coefficients to represent the respiratory movement during exercise [2].…”

Monitoring of Vital Signs with Flexible and Wearable Medical Devices

“…[ 47,48 ] These types of sensors can be highly accurate and can more easily detect certain conditions than chest-based sensors, such as respiratory obstructions in which air stops fl owing into the lungs despite continued motion of the chest. [ 45,49 ] Strain sensors on the torso also tend to respond to other body motions in addition to respiration, such as walking, speaking, and arm movement, [ 43,49,50 ] whereas sensors on the nose and throat are not susceptible to such motion artifacts. However, sensors on the nose and throat are likely to be more conspicuous and less comfortable than those on the torso.…”

Validation of a Polyvinylidene Fluoride Impedance Sensor for Respiratory Event Classification during Polysomnography

“…In contrast, impedance measures changes in electrical resistance, which usually are not linearly related to changes in cross-sectional dimensions. [12][13][14] Consistent with evidence-based guidelines on sensor evaluation, we evaluated the comparability of respiratory event and effort detection when using PVDF impedance belts (PVDFb) compared to currently recommended sensors, including RIP, NPT, heat-sensitive thermistry, and nasal-oral pneumotachography (PNT).…”