A DOUBLE-BLIND EVALUATION OF SODIUM-GRADIENT HEMODIALYSIS

In a double-blind, crossover trial, 7 chronic hemodialysis patients underwent three 4-wk treatment periods. During 1 period, dialysate contained 135 meq/l Na. During another period, dialysate contained 143 meq/l Na. During the remaining period Na gradient dialysate was used, the Na concentration of which was decreased from 160 to 133 meq/l during each 4 h dialysis session. Ultrafiltration was performed at a constant rate to achieve a predetermined post-dialysis weight. Interdialytic weight gain, thirst, blood pressure control, and incidence of side effects were monitored. There was a significant difference in interdialytic weight gain for the 3 treatments (P = 0.005). Interdialytic weight gain using 135 meq/l Na dialysate (2.2 .+-. 0.9 kg, mean .+-. SD) was significantly less than that using either 143 meq/l Na dialysate (2.6 .+-. 0.8 kg) or Na gradient dialysate (2.8 .+-. 0.7 kg). Self-reported thirst tended to be less severe with 135 mgq/l Na dialysate than with 143 meq/l Na dialysate or with Na gradient dialysate, but changes in thirst were not statistically significant (P = 0.13). The incidence of intradialytic hypotensive episodes was comparable with the 3 levels of dialysate Na. The described Na gradient method apparently does not prevent the increased interdialytic weight gain and thirst seen with other forms of high-Na dialysis, and probably does not reduce the incidence of side effects.