In a mixed solution with several electrolytes, the apparent diffusion coefficient of the respective ions —especially that of bivalent ions—varies in terms of the partial equivalent ratios of ions. When a high sodium dialysate is used for dialysis, the same kind of variation in the apparent permeability of the respective ions is found. Thus, calcium transfer to the body is much less with a high sodium dialysate, compared to a low one. In dialysis with 12 patients using dialysate Na, Cl and Ca levels at 132, 101.5 and 3.0mEq/l, respectively, dialysate was changed after 1 hour for 5 min, to one with Na and Cl levels of 160 and 129.5 mEq/l, respectively, keeping other ion levels the same. After measuring calcium transfer to the body for 5min., dialysate was replaced by the initial one, and measurements repeated. Results showed mean calcium transfer of 0.38mEq/5min. with the low sodium dialysate against a significantly lower 0.11mEq/5min. with the high one. This finding indicates a need to elevate calcium level in higher sodium dialysate to prevent the accompanying side effects of reduced calcium transfer.
