Calcium-free dialyzate: development and applications.

A calcium-free, bicarbonate-containing concentrate was prepared for hemodialysis, which, after dilution, gave analyzed concentrations of sodium of 146 mmol/l, Cl 110 mmol/l, HCO3 of 35 mmol/l and pH of 8.3. When compared with standard bicarbonate dialysis, no important differences in blood chemistries, symptoms or signs were seen. The solution has been trouble-free in over 300 dialyses. Total amount of calcium lost uncorrected for time, dialyzer or blood flow was 40.6 +/- 1.1 mmol, n = 62. This loss was replaced by a calcium infusion into the venous line giving 40 mmol calcium over 4 h. The dialyzate calcium loss could be accurately predicted by sampling without collecting the total dialyzate volume. The uses of this concentrate for bicarbonate dialysis, citrate anticoagulation and avoidance of hypercalcemia in patients treated with oral calcium for phosphate binding is discussed.