Validation of Remote Dielectric Sensing (ReDS™) Technology for Quantification of Lung Fluid Status: Comparison to High Resolution Chest Computed Tomography in Patients with and Without Acute Heart Failure

Background: Pulmonary congestion is a common presentation of acute decompensated heart failure (ADHF). The ability to quantify increased pulmonary parenchymal water content in chest computed tomography (CCT) is well known. However, availability and radiation limitations make it unsuitable for serial assessment of lung fluid content. The ReDS™ technology allows quantification of lung fluid content.

Objective: The objective of this work was to validate the ability of the ReDS™ technology to quantify total lung fluid when compared with CCT in ADHF and non-ADHF patients.

Methods: Following CCT, ReDS measurements were obtained from consented subjects. ReDS measurements were then compared to the CCT using lung density analysis software. CCT results were converted from Hounsfield Units to percentage units, allowing comparison with the ReDS readings. The analyses, performed on 16 ADHF and 15 non-ADHF patients, were conducted by an independent observer blinded to ReDS outcomes.

Results: The fluid content averages and standard deviations for the non-ADHF group were 28.7±5.9% and 27.3±6.6% and for the ADHF patients 40.7±8.8% and 39.8±6.8% (CCT and ReDS respectively). Intraclass correlation was found to be 0.90, 95% CI [0.8-0.95]. Regression analysis yielded a slope of 0.94 (95% confidence interval [0.77-1.12]) and intercept 3.10 (95% confidence interval of [-3.02-9.21]). The absolute mean difference between the quantification of the two methods was 3.75 [%] with SD of 2.22 [%].

Conclusion: Current findings show high correlation between the ReDS noninvasive system and CCT in both ADHF and non-ADHF patients. Remote patient monitoring using ReDS™ based system may help in the management of patients with heart failure.