Assessment of dry weight in dialysis: diagnostic tools

Assessment of hydration status in dialysis patients is essential for appropriate clinical management, as both dehydration and overhydration are associated with increased morbidity, mortality, and healthcare costs. In dialysis patients, excess fluid is mainly distributed in the extracellular compartment, particularly in the interstitial space. Estimation of euvolemia may be based on clinical examination, but increasingly relies on instrumental methods, including echocardiography, with left atrial volume assessment as an indicator of volume expansion, although it may be influenced by concomitant cardiac diseases. Inferior vena cava diameter and collapsibility are useful parameters but show significant variability. Bioimpedance analysis represents a rapid and validated method forestimating total body water, despite limitations in individual accuracy. Intradialytic blood volume monitoring helps identify volume status changes during dialysis sessions. Finally, ultrasound B-lines are a sensitive marker of pulmonary congestion and correlate with cardiovascular outcomes and response to ultrafiltration. The integration of these tools may significantly improve dry weight assessment and enable more personalized patient management.