Thoracic ultrasound in hemodialysis: Assessing fluid overload and dialysis efficacy

Fluid overload in patients with end-stage kidney disease (ESKD) usually results in pleural effusions (PEs). While volume overload remains the primary etiology of PE, other possible causes must be ruled out. Thoracic ultrasonography (TUS) is a practical and efficient method for evaluating volume in patients undergoing hemodialysis (HD), although evidence regarding its usefulness in this context is limited. We aimed to investigate the relationship between pleuropulmonary TUS patterns and overload symptoms and their correlation with optimal HD, as measured by total urea clearance (Kt/V) and the urea reduction rate (URR). This prospective longitudinal observational study included patients with ESKD who underwent renal replacement therapy with HD. Point-of-care TUS was performed before and after HD sessions. The ultrasound parameters recorded included the presence, location, sonographic patterns and volume of PE. A total of 136 patients were included in the study. TUS abnormalities compatible with interstitial syndrome (B-lines) were identified in 56 (41%) patients. Forty-four patients (32%) had PE. The PE volume showed a statistically significant decrease after HD and normalized in 12% of the patients. No significant difference in the proportion of patients who achieved a URR > 65 or optimal Kt/V was observed between patients with abnormal (B-lines) and normal TUS results (P = .39). The presence of PE and B-lines was significantly associated with overload symptoms; however, these overload symptoms were not related to optimal HD, as measured by the Kt/V or URR. PE and B-lines demonstrated a stronger association with overload symptoms than Kt/V or URR in HD patients. No relationship was found between the TUS pleuropulmonary changes and HD efficacy.