Robin Callan

Dialysate made from dry chemicals using citric acid increases dialysis dose

A new dry dialysate concentrate acidified with citric acid (citrate dialysate) has been used in two separate clinical studies of hemodialysis patients. The first compared a single treatment using this dialysate, with one dialysis using regular standard dialysate acidified with acetic acid (regular dialysate) in a prospective, randomized, crossover study of 74 dialyses. Changes in blood levels of electrolytes and other blood constituents during dialysis were calculated by subtracting postdialysis from predialysis blood concentrations. Compared with acetic acid dialysate, citrate dialysate was associated with significantly greater decreases in total and ionized calcium, magnesium, and chloride levels. Citrate dialysate was also associated with greater increases in serum sodium and citrate concentrations, although their postdialysis concentrations remained within or just outside normal ranges. Changes in other blood constituents were similar with both dialysates. The second study used citrate dialysate exclusively for all dialyses over a 12-week period in 25 patients. Predialysis blood samples were drawn at the start of the study and at 4-week intervals thereafter, and postdialysis blood samples were obtained after the first and last dialysis. Repeated-measure analysis showed that although predialysis blood concentrations of magnesium, potassium, and citrate remained within the normal range, there was a significant declining trend over the course of the study. At the same time, predialysis serum bicarbonate levels increased, and significantly more patients 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, chi-square). In 19 patients (excluding 3 patients for whom the type of dialyzer was changed during the study), the dose of dialysis for the first and last dialysis was calculated by urea reduction ratio and Kt/V. There was a significant increase in both measurements without changes in dialysis time, blood and dialysate flows, or dialyzer used. The urea reduction ratio increased 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, respectively. In conclusion, this citric acid dialysate was well tolerated, and intradialytic changes in blood chemistries were similar to those seen with regular dialysate. Using dialysate containing citric instead of acetic acid increases the delivered dialysis dose.

Increased Efficiency of Hemodialysis with Citrate Dialysate: A Prospective Controlled Study

BACKGROUND AND OBJECTIVES A bicarbonate dialysate acidified with citrate (CD) has been reported to have local anticoagulant effect. This study examines the effect of CD on dialysis efficiency, measured as eKt/Vurea, and predialysis concentrations of BUN, creatinine, phosphate, and beta-2 microglobulin in chronic dialysis units. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS Three outpatient chronic hemodialysis units with 142 patients were switched to CD for 6 mo. Using each patients prior 6 mo on regular bicarbonate dialysate acidified by acetate (AD) as control, eKt/Vurea was compared with that of CD. Follow-up data for 7 mo after the study were collected from about one-half of the participants remaining on CD and the others returned to AD. RESULTS eKt/Vurea, increased (P < 0.0001) from pre-CD value of 1.51 +/- 0.01 to 1.57 +/- 0.01 with CD. During CD use beta-2 microglobulin levels declined (P = 0.0001) from 28.1 +/- 10.0 to 25.9 +/- 10.0. Similarly, the concentrations of BUN, creatinine, and phosphate also decreased on CD (P < 0.008). In the poststudy period, eKt/Vurea for the patients staying on CD remained unchanged at 1.60 +/- 0.17 versus 1.59 +/- 0.18 (P = NS), whereas in those returning to AD the eKt/Vurea decreased from 1.55 +/- 0.20 to 1.52 +/- 0.17 (P < 0.0001). CONCLUSIONS Data suggest that CD use is associated with increased solute removal.

Increased dialyzer reuse with citrate dialysate

Dialyzer reuse is limited by the clotting of blood, which blocks the fibers and reduces the membrane surface area. Clotting during treatment may also reduce dialysis efficiency and potentially decrease delivered dose, Kt/Vurea. A new dialysate containing citric acid, instead of the standard acetic acid, as the acidifying agent has become available and is associated with reduced clotting during acute dialysis treatments. The effect of citric acid dialysate on dialyzer reuse was evaluated in this prospective, controlled, multicenter study involving maintenance hemodialysis patients. A total of 105 patients from five dialysis units were switched to the new dialysate and new dialyzers. Reuse outcome on the new dialysate was compared with the reuse on the regular acetic acid containing bicarbonate dialysate (controls). The overall reuse with citrate dialysate increased significantly from 15.1 ± 9.4 to 18 ± 10.0 (mean ± SD) on regular and citrate dialysate, respectively (p = 0.0003). The most significant increase was seen in those patients who had limited reuse before the switch to citrate dialysate; 51, 59, and 134% increases occurred in those with 10 to 15, 5 to 10, and < 5 reuses at controls, respectively. Interestingly, the 10 patients with 10 or fewer reuses had significantly lower Kt/Vurea at baseline (before the switch to citric acid dialysate) than those with > 10 reuses (1.23 ± 0.23 vs. 1.47 ± 0.23, respectively, p = 0.009). The Kt/Vurea increased to 1.41 ± 0.31 after the switch in the low‐reuse group but the increase did not reach statistical significance (p = 0.07). The results from this study show that citric acid–containing dialysate is associated with increase in dialyzer reuse and appears to be related to reduced clotting.