The Chronic Efficacy and Safety of High Sodium Dialysate: Double-Blind, Crossover Study

The symptomatic benefits of high osmolality dialysate have been established in acute dialysis studies, but the long-term effects have not been completely elucidated. We therefore examined the symptomatic responses to 6-wk courses of a high sodium dialysate (HNa; 144 mEQ/liter) or standard sodium dialysate (RNa; 132 mEQhiter) in 10 chronic dialysis patients using a double-blind, crossover design. Use of HNa dialysate was associated with fewer hypotensive episodes (systolic BP <90 mmHg, 2.4 ± 0.6 vs. 8.0 ± 0.4 episodes/patient/6 wk, p < 0.02), fewer bouts of nausea, vomiting or cramping (6 ± 1.2 vs. 11.5 ± 1.5 epidoses/patient/6 wk, p <0.005), and fewer requirements for supplemental volume therapy with saline or mannitol (5.7 ± 1.9 vs. 15 ± 2.3 treatments/patient/6 wk, p <0.005). Beginning of the week plasma sodium concentration (142 ± 0.6 vs. 140 ± 0.9 mEQ/liter, p <0.02) and plasma osmolality (316 ± 1.4 vs. 313 ± 1.8 mosmlkg H20, p <0.005) were greater during the HNa protocol. Similarly, beginning of the week weight (69.1 ± 4 vs. 68.3 ± 4 kg, p <0.05) and mean interdialytic weight gains (2.3 ± 0.2 vs. 1.8 ± 0.2 kg, p <0.001) , were greater when patients were receiving the HNa dialysate. Weight loss on dialysis was greater during the HNa protocol (2.4 ± 0.2 vs. 1.8 ± 0.2 kg, p <0.001) so that postdialysis weights were comparable in both protocols. Supine predialysis mean blood pressures were comparable (HNa,103 ± 3 vs. RNa,100 ± 2 mmHg, NS). These results demonstrate that the use of HNa affords striking improvement in blood pressure stability and symptomatic tolerance to dialysis. Although an increase in interdialytic weight gain was observed in the HNa protocol, the extra volume was readily removed and did not increase predialysis blood pressure.