Combined ultrasonographic and clinical assessment of bioimpedance-defined volume status in dialysis patients: a...

Accurate assessment of volume status in dialysis patients remains challenging, and no single method is universally accepted. This study aimed to evaluate the combined diagnostic performance of lung ultrasonography and physical examination for predicting bioimpedance spectroscopy (BIS)-defined volume overload.

In this cross-sectional study, 44 dialysis patients underwent clinical evaluation, lung ultrasonography, inferior vena cava assessment, and BIS measurement. Clinically significant volume overload was defined as BIS-derived overhydration ≥ 2500 mL. The diagnostic performance of B-line count and pretibial edema was assessed using logistic regression and receiver-operating characteristic (ROC) analysis.

Volume overload was significantly associated with B-line count and pretibial edema. In multivariable analysis, both parameters remained independent predictors of volume status, with B-line count demonstrating the strongest individual predictive performance. The addition of pretibial edema significantly improved overall model fit and provided incremental diagnostic value beyond B-line count alone. The combined model showed good discriminative ability for identifying hypervolemic dialysis patients, with an area under the curve (AUC) of 0.941 (95% CI 0.879-1.000).

The combined use of bedside lung ultrasound-derived B-lines with pretibial edema assessment demonstrates good discriminatory performance for identifying clinically relevant overhydration in dialysis patients and may serve as a practical, noninvasive adjunct to bioimpedance analysis, particularly in settings where BIS is not readily available.