Remote dielectric sensing for pulmonary congestion assessment: current concepts and clinical perspectives

Figures

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  Figure 1. Overview of the ReDS system. The wearable device consists of anterior and posterior sensors that transmit low-power electromagnetic signals through the thorax. The received signals are analyzed to estimate lung fluid content, which is displayed as the ReDS value within ∼1 min

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  Figure 2. Principles of ReDS. Because water has a substantially higher dielectric constant than air, the dielectric properties of the lung vary according to the relative proportions of air and fluid. By analysing electromagnetic signals transmitted through the thorax, ReDS quantitatively estimates the percentage of lung volume occupied by fluid

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  Figure 3. Relationship between pulmonary congestion, illustrative chest CT findings, and ReDS values. Increasing pulmonary fluid accumulation is accompanied by progressive radiographic abnormalities on chest CT and higher ReDS values. ReDS provides a quantitative estimate of pulmonary fluid content across the spectrum of congestion severity. Values are illustrative and do not represent validated severity thresholds

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  Figure 4. Conceptual relationship among systemic volume status, intracardiac filling pressure, and pulmonary fluid measured by ReDS. These physiological domains sometimes overlap but are not interchangeable. CKD, chronic kidney disease; LVEDP, left ventricular end-diastolic pressure; PCWP, pulmonary capillary wedge pressure

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  Figure 5. Factors influencing ReDS measurements. Physiological conditions (respiratory phase and exercise), patient characteristics (body habitus and thoracic anatomy), and pulmonary comorbidities (e.g. chronic obstructive pulmonary disease and pleural effusion) may affect ReDS values independent of changes in pulmonary fluid. Standardized measurement conditions and appropriate clinical interpretation are therefore essential

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  Figure 6. Proposed clinical workflow for integrating ReDS into multimodality congestion assessment. ReDS values and temporal trends should be interpreted together with clinical findings and complementary modalities to inform individualized decongestive management. No universally validated ReDS-guided therapeutic threshold has been established