[Extracellular hydration status and residual urinary sodium excretion in chronic hemodialysis patients: a cross-sectional multicenter study]. / Statut d'hydratation extracellulaire et natriurèse résiduelle en hémodialyse chronique : une étude transversale multicentrique.

BACKGROUND: In dialysis patients, a misevaluation of dry weight may lead to an increased morbidity and mortality. The aim of this cross-sectional multicenter study was to evaluate the association between residual urinary sodium excretion and extracellular volume status in chronically treated hemodialysis patients. PATIENTS AND METHODS: Dry weight was determined clinically and by whole-body bioimpedance spectroscopy (Body Composition Monitor, Fresenius Medical Care) prior to a mid-week session in 40 chronic hemodialysis patients with significant residual diuresis (more than 250 mL per day) and receiving treatment in four dialysis centers. Regarding their hydration status assessed by the Body Composition Monitor and in comparison to a healthy reference population, patients were assigned to 1 of the 3 categories: overhydrated, normohydrated and dehydrated. Urine output, urinary sodium excretion and residual renal function were measured for all patients within 30 days before dry weight assessment. RESULTS: The median post-HD session FO was of-0.40 L (IQR: from-1.95 to+0.90) and the median residual urinary sodium excretion was of 64 mmol/L (IQR: 46-79). Among these patients, 16 were normohydated, 16 were dehydrated and 8 were overhydrated. There was a linear relationship between the hydration status after HD session and the urinary sodium excretion (estimate: 5.6±1.5; p<0.001). Compared with normohydrated patients, overhydrated patients had a higher residual urinary sodium excretion (estimate: 26±10; p<0.01). CONCLUSION: In this study, urinary sodium excretion is associated with the hydration status evaluated by whole-body bioimpedance spectroscopy.

Elevated removal of middle molecules without significant albumin loss with mixed-dilution hemodiafiltration for patients unable to provide sufficient blood flow rates.

BACKGROUND: We examined the hypothesis that mixed-dilution online hemodiafiltration (MIXED) rather than predilution online hemodiafiltration (PRE) could enable patients with low blood flow rate (Qb) to benefit from advantages of convective therapies. METHODS: Thirty-eight patients were included in a prospective, randomized, crossover and multicenter study conducted with a view to comparing the equilibrated Kt/V, reduction ratio (RR) of phosphates, ß2-microglobulin (ß2-M) and myoglobin (myo) between PRE and MIXED, each at two Qb values of 250 and 300 ml/min during 4 h sessions with a FX1000HDF dialyzer. Albumin losses (Alb) were also measured in 12 patients. RESULTS: MIXED was always found to be more efficient compared to PRE notably for middle molecules (MM). RRß2-M: MIX250: 81.3 ± 3.6 vs. PRE250: 75.2 ± 5.9; MIX300: 82.7 ± 3.6 vs. PRE300: 78.1 ± 5.4; RRmyo: MIX250: 70.2 ± 3.6 vs. PRE250: 42.6 ± 2.6; MIX300: 70.6 ± 3.6 vs. PRE300: 45.7 ± 3.6 and with Alb <3.0 g/session. CONCLUSION: MIXED allows patients unable to provide sufficiently high Qb to achieve high levels of MM removal.