Wearable Bioimpedance Measurement for Respiratory Monitoring During Inspiratory Loading

Abstract

Bioimpedance is an unobtrusive noninvasive technique to measure respiration and has a linear relation with volume during normal breathing. The objective of this paper was to assess this linear relation during inspiratory loading protocol and determine the best electrode configuration for bioimpedance measurement. The inspiratory load is a way to estimate inspiratory muscle function and has been widely used in studies of respiratory mechanics. Therefore, this protocol permitted us to evaluate bioimpedance performance under breathing pattern changes. We measured four electrode configurations of bioimpedance and airflow simultaneously in ten healthy subjects using a wearable device and a standard wired laboratory acquisition system, respectively. The subjects were asked to perform an incremental inspiratory threshold loading protocol during the measurements. The load values were selected to increase progressively until the 60% of the subject's maximal inspiratory pressure. The linear relation of the signals was assessed by Pearson correlation (r) and the waveform agreement by the mean absolute percentage error (MAPE), both computed cycle by cycle. The results showed a median greater than 0.965 in r coefficients and lower than 11 % in the MAPE values for the entire population in all loads and configurations. Thus, a strong linear relation was found during all loaded breathing and configurations. However, one out of the four electrode configurations showed robust results in terms of agreement with volume during the highest load. In conclusion, bioimpedance measurement using a wearable device is a noninvasive and a comfortable alternative to classical methods for monitoring respiratory diseases in normal and restrictive breathing. INDEX TERMSBioimpedance, chronic respiratory diseases, electrode configurations, inspiratory threshold protocol, wearable. DOLORES BLANCO-ALMAZÁN received the M.Sc. degree in telecommunications engineering from the

Localized Bicep Tissue Bioimpedance Alterations Following Eccentric Exercise in Healthy Young Adults

“…To continue to advance understanding of how tissue bioimpedance changes post-exercise and as a result of daily living, portable/wearable equipment is needed that can collect data over minutes, hours, and weeks in free-living environments. Though the efforts of multiple research groups to advance designs for wearable systems [13], [19], [20] supports that such tools are likely to become available to continue wider studies in the application of bioimpedance measurements.…”

“…While a Keysight E4990A was utilized in this work based on its availability to the research team, other commercially available instruments that can measure tissue bioimpedance include the ImpediMed SFB7 (ImpediMed Ltd, USA), Solartron 1260A Impedance Analyzer (Solartron Analytical, Hampshire, UK), or Zurich Instruments MFIA Impedance Analyzer (Zurich Instruments, Zurich, Switzerland). Additionally, custom electronics systems developed by other researcher groups have been published in the literature for implementation [13], [20], [23].…”

“…The electrical properties of a tissue under study are dependent on the cell population, cell volumes, cellular membrane integrity, and intra / extra cellular fluids of the tissue. The use of bioimpedance as a monitoring tool is being actively investigated to assess soft tissue damage [9], [10], to assess knee and ankle joint health [11]- [13], manage fluid overload [14], assess neuromuscular disorders [15], [16], track impaired muscles in neurological injury patients [17], [18], measure blood pressure [19], and for respiratory monitoring [20]. With respect to applications for characterizing skeletal muscle, EIM is being investigated to quantify tissue changes during contraction in human subjects [21], [22] and mice [23] and to quantify changes that result from activity/exercise in human subjects [22], [24], [25].…”

Portable Detection of Apnea and Hypopnea Events Using Bio-Impedance of the Chest and Deep Learning

“…In various medical domains, bioZ measurements have already been suggested for measuring, among others, respiration of the patient [41], [42]. However, the use of bioZ for sleep apnea detection has not yet been thoroughly analyzed or described.…”

Cole-impedance parameters representing biceps tissue bioimpedance in healthy adults and their alterations following eccentric exercise

“…Tissue bioimpedance is related to the type of tissue, intra/extra cellular fluids, and overall tissue structure [3] . Bioimpedance measurements have been utilized for applications including: body composition determination [4] , [5] , clinical tomography [6] , cardiography [7] , respiratory monitoring [8] , and even food monitoring applications [9] . Bioimpedance is also currently being investigated as a noninvasive technique to characterize skeletal muscle tissue with a particular focus on assessing neuromuscular disorders [10] , [11] , [2] .…”