Integrated Ultrasound Approach to Fluid Assessment and Nutritional Status in Hemodialysis

Fluid overload is a major determinant of morbidity and mortality in maintenance hemodialysis (MHD) patients. This exploratory study describes the integration of lung ultrasound (LUS), modified Venous Excess Ultrasound Score (mVExUS), and bioimpedance analysis (BIA) for non-invasive fluid status assessment in MHD. Additionally, this study aimed to correlate congestion with malnutrition using echographic parameters (nutritional ultrasound [NUS]) in congestive and non-congestive patients.

In this single-center retrospective observational cohort study, 47 adult patients on MHD underwent pre-dialysis evaluation with LUS, mVExUS, NUS, and BIA. Patients were classified as congestive if they had an mVExUS score ≥2, LUS with ≥3 B-lines in ≥3 thoracic zones and BIA with the ratio of extracellular water to total body water ECW/TBW ≥0.39. NUS was used to assess the quadriceps rectus femoris (QRF) and preperitoneal visceral fat (PPVF), measuring Y-axis, Y-axis/height, cross-sectional muscle area rectus femoris (CS-MARF), and supramuscular fat (SMF). Demographic, biochemical, functional, and dialysis-related parameters were collected. Frailty, sarcopenia and nutritional status were evaluated. Congestive patients were reassessed after 5 weeks.

Eight patients (17%) met criteria for congestion. As expected by the predefined congestion criteria, patients classified as congestive showed higher mVExUS grades (p < 0.001), greater B-line burden (11.9 vs. 2.9), and higher ECW/TBW ratios (0.42 vs. 0.40; p = 0.004). After 5 weeks, congestive patients exhibited improvements in N-terminal pro-B-type natriuretic peptide (NT-proBNP), portal vein pulsatility index, and pulmonary congestion, without adverse hemodynamic events. The CS-MARF was 1.81 ± 0.11 cm2 in congestive versus 2.91 ± 0.78 cm2 in non-congestive (p = 0.0004).

The integration of LUS, mVExUS, BIA and NUS provide a descriptive framework for multimodal assessment of fluid and nutritional status in MHD patients. These findings should be considered hypothesis-generating and require validation in prospective studies.