Role of Bioimpedance Spectroscopy, Lung Ultrasound, and Inferior Vena Cava Diameter in Assessing Dry Weight in Hemodialysis Patients: A Narrative Review

Accurate dry weight assessment is crucial for hemodialysis (HD) fluid management, yet traditional clinical methods often lack precision. A significant scientific gap exists in the availability of a standardized multimodal framework for integrating objective tools, leaving clinicians without clear guidance on combining results from multiple devices. To address this gap, this narrative review provides a qualitative clinical synthesis of bioimpedance spectroscopy (BIS), lung ultrasound (LUS), and inferior vena cava diameter (IVCD). A structured literature search was conducted across PubMed, Scopus, and CINAHL for English-language studies published between 2012 and 2024. Studies focusing on dry weight assessment using these tools in adult HD patients were included, and findings from 22 core studies were synthesized narratively. BIS and LUS are valuable tools for identifying fluid overload. BIS assesses systemic fluid distribution across compartments, whereas LUS allows non-invasive detection of extravascular lung water. In contrast, IVCD primarily reflects intravascular volume status. While the integrated use of these tools shows potential clinical utility, individual methods, particularly IVCD, require further validation owing to interpatient variability. A multimodal approach that integrates these objective methods with clinical judgment offers a comprehensive evaluation of dry weight. Integrating these assessment strategies may improve outcomes and decision-making in nephrology care.