Dialysate made from dry chemicals using citric acid increases dialysis dose

A new dry dialysate concentrate acidified with citric acid (citrate dialysa te) has been used in two separate clinical studies of hemodialysis patients . The first compared a single treatment using this dialysate, with one dial ysis using regular standard dialysate acidified with acetic acid (regular d ialysate) in a prospective, randomized, crossover study of 74 dialyses, Cha nges in blood levels of electrolytes and other blood constituents during di alysis were calculated by subtracting postdialysis from predialysis blood c oncentrations. Compared with acetic acid dialysate, citrate dialysate was a ssociated with significantly greater decreases in total and ionized calcium , magnesium, and chloride levels. Citrate dialysate was also associated wit h greater increases in serum sodium and citrate concentrations, although th eir postdialysis concentrations remained within or just outside normal rang es. Changes in other blood constituents were similar with both dialysates. The second study used citrate dialysate exclusively for all dialyses over a 15-week period in 25 patients. Predialysis blood samples were drawn at the start of the study and at 4-week intervals thereafter, and postdialysis bl ood samples were obtained after the first and last dialysis, Repeated-measu re analysis showed that although predialysis blood concentrations of magnes ium, potassium, and citrate remained within the normal range, there was a s ignificant declining trend over the course of the study. At the same time, predialysis serum bicarbonate levels increased, and significantly more pati ents had a predialysis bicarbonate concentration within the normal range at the end of the study than at the start (15 versus 8 patients; P = 0.001, c hi-square). In 19 patients (excluding 3 patients for whom the type of dialy zer was changed during the study), the dose of dialysis for the first and l ast dialysis was calculated by urea reduction ratio and Kt/V. There was a s ignificant increase in both measurements without changes in dialysis time, blood and dialysate flows, or dialyzer used. The urea reduction ratio incre ased from 68% +/- 5.9% to 73% +/- 5.3% (P < 0.03), and the Kt/V from 1.23 /- 0.19 to 1.34 +/- 0.20 (P = 0.01) from the first to last dialysis, respec tively. In conclusion, this citric acid dialysate was well tolerated, and i ntradialytic changes in blood chemistries were similar to those seen with r egular dialysate. Using dialysate containing citric instead of acetic acid increases the delivered dialysis dose. (C) 2000 by the National Kidney Foun dation, Inc.