Remote Dielectric Sensing Technology in Heart Failure: Correlating Lung-Fluid Volume Shifts with Postural Changes and Dyspnea Severity

Abstract

Background

Orthopnea, a common symptom in heart failure (HF), arises from elevated pulmonary pressures and interstitial edema due to positional shifts. Remote dielectric sensing (ReDS) offers a noninvasive method to quantify lung-fluid volume. This study evaluated ReDS system measurements in response to posture changes in HF patients, and the correlation of these measurements with dyspnea severity.

Methods

This prospective observational study included both healthy volunteers and HF patients. Lung-fluid volume was measured using the ReDS system, with the patients in 3 positions—sitting, supine, and supine with elevated legs. HF patients additionally reported dyspnea levels on a visual analog scale immediately before and after ReDS measurements were made.

Results

A total of 86 healthy volunteers and 20 HF patients were included in the study. In healthy volunteers, ReDS values modestly increased when patients changed from a sitting to a supine position (21% vs 22%; P <0.001), and from being supine to supine with raised legs (22% vs 24%; P <0.001). In contrast, HF patients showed significantly higher ReDS values across all positions (29%, 31%, and 34%, respectively), with more pronounced increases between positions compared to those of healthy subjects (P for interaction < 0.001). A strong correlation was observed between ReDS system measurements and dyspnea visual analog scale scores in HF patients following posture changes (Pearson’s r = 0.718, P < 0.001).

Conclusions

The ReDS system effectively quantifies lung-fluid volume changes due to body-position shifts in HF patients. Its measurements correlate well with alterations in dyspnea severity, potentially offering an objective means to monitor HF symptoms. Further studies are needed to validate these findings in a larger cohort and over an extended period.