Twelve patients underwent hemodialysis using dialysate containing 130 mEq/L sodium, and, on a separate occasion, dialysis using a dialysate of constantly decreasing sodium concentration (from 150 to 133 mEq/L). Hydrostatic ultra-filtration during dialysis was performed at a constant rate (900 ml/hr) during both treatments, and was continued until a substantial drop in mean arterial pressure (-15%) or symptoms were observed. A double-blind comparison of the two treatment modalities was thus achieved.
At the end of ultrafiltration, significantly more fluid had been removed using decreasing sodium dialysate (2.9 ± 0.3 kg) than when using the low-sodium dialysate (1.9 ± 0.2 kg, P<0.001). Plasma sodium concentration at the end of ultra filtration using decreasing sodium dialysate was not significantly different from the predialysis level.
Hydrostatic ultrafiltration using a dialysate of decreasing sodium level may prove to be a useful means of removing excess fluid asymptomatically from dialysis patients.