Fluid status assessment in hemodialysis patients and the association with outcome: review of recent literature

Purpose of reviewIn this review, we will discuss the most recent literature regarding fluids status assessment in hemodialysis patients, and the associations with outcome.Recent findingsResearch toward technique-assisted assessment of fluid status in hemodialysis patients has been going on for many years. However, there is no absolute agreement between techniques, such as bioimpedance, lung ultrasound, biochemical markers or vena caval diameter, likely because they reflect different fluid compartments with potentially altered distribution in hemodialysis patients. Recent studies, mostly based on bioimpedance, have shown not only an association of severe, but also of moderate predialysis fluid overload with overall survival. Also predialysis fluid depletion has been found to associate with and increased mortality risk. Interventional studies with fluid-guided management are scarce and outline the difficulties of achieving dry weight is the dialysis population.SummaryOptimal estimation of predialysis fluid status remains challenging and may require a combination of clinical and technical derived parameters. There appears to be a narrow window of optimal predialysis fluid status. Further clinical studies are necessary to identify strategies to improve survival in hemodialysis patients with abnormalities in fluid status.