Ultrasonographic Evaluation of Systemic Venous Congestion in Maintenance Hemodialysis Patients during Fluid Removal

Fluid overload is a frequent and serious complication in hemodialysis patients. The combination of multiple point-of-care ultrasound (POCUS) measurements can identify significant venous congestion, but its usefulness to determine ultrafiltration (UF) requirements and dry weight is unknown. Therefore, we evaluated prospectively patients in maintenance hemodialysis to establish the correlations between changes in venous congestion parameters and fluid removal.

This was a prospective, single-center, observational study. POCUS venous congestion measurements were performed in 22 patients during 32 online post-dilutional hemodiafiltration sessions, and findings were correlated with UF volume, central venous pressure, and body water composition determined by multifrequency bioelectric impedance analysis (BIA).

The pre-dialysis weight was on average 1.9 kg above the BIA estimated dry weight, the average initial inferior vena cava (IVC) diameter was <2 cm. An initial abnormal hepatic vein (HV) waveform was present in 26% (8) of the measurements. The average UF volume was 2,084 ± 655 mL and correlated with changes in IVC diameter (R = 0.34, 95% CI: [0.18, 0.56], p < 0.05) but not with any other POCUS venous congestion parameters. Normalization of the IVC diameter and HV waveform was observed during the first UF hour in all initially altered measurements. Diameter reduction in the IVC correlated with total body water volume reduction estimated with BIA when measured immediately after fluid removal (R = 0.34, 95% CI: [0.08, 0.56], p < 0.05).

Reduction in IVC diameter had a modest but significant correlation with UF volume in our patients on maintenance hemodiafiltration. POCUS may be used to monitor patients during UF.