Volume Assessment in Hemodialysis: A Comparison of Present Methods in Clinical Practice with Sonographic Lung Comets

Dry weight assessment in dialysis patients remains a challenging endeavor owing to the limitations of the available methods for volume assessment. Lung ultrasound is emerging as an invaluable tool to assist in the appropriate assessment and assignment of dry weight. The objectives of this study are (1) to determine the reliability of clinical signs and symptoms for volume assessment, (2) to compare lung ultrasound with High Resolution Computed Tomography (HRCT) chest-A noninvasive gold standard tool for detecting pulmonary congestion and with inferior vena cava diameter (IVCD) - another time-tested volume assessment method, and (3) to analyze if lung ultrasound could detect dialysis induced fluid status variations. The cross-sectional study involves 50 patients on maintenance hemodialysis. Lung ultrasound for B line estimation and ultrasonographic measurement of IVCD performed before and after hemodialysis by a nephrologist trained in ultrasonography. Limited HRCT was obtained just before hemodialysis. Edema, crackles, and dyspnea had a poor sensitivity of 37.9%, 11.5%, and 52.6%, respectively, to detect clinically significant pulmonary congestion by lung ultrasound. A highly significant correlation was obtained between B-line score and HRCT signs of pulmonary congestion (P < 0.001) before dialysis. B lines showed statistically significant reduction with dialysis. The absolute reduction of B lines showed significant correlation with ultrafiltration volume and weight loss. Bedside lung ultrasound appears a sensitive tool for evaluating real-time changes in extravascular lung water and would serve to optimize volume status in dialysis patients.