INTRADIALYTIC CALCIUM BALANCES WITH DIFFERENT CALCIUM DIALYSATE LEVELS

It has been shown that calcium carbonate (CaCO3) is an effective phosp hate binder which is less toxic than Al(OH)(3). However, given that it s use with standard calcium dialysate (CaD) levels may lead to hyperca lcemia, a decrease in CaD levels has been proposed. The aim of the pre sent study was to evaluate the acute clinical and biochemical conseque nces of a lowering of CaD in HD patients. Dialysate composition was ot herwise the same. (I) Blood pressure levels (BP) during short hemodial ysis were measured in a group of 12 patients who underwent alternate h emodialyses with dialysate calcium of 1.75 and 1.25 mmol/l. (2) Ca2+ a nd PTH kinetics during short hemodialysis were studied in a group of 6 patients who were sequentially treated with 1.75 and 1.25 mmol/l CaD. The results show: (1) that cardiovascular stability in chronic HD pat ients during short HD sessions with low CaD (LCaD) may be good; (2) th at a single treatment with standard CaD (SCaD) produces positive calci um balances (JCa(2+)) with Ca2+ plasma increase and PTHi inhibition at the end of HD sessions; during HD with LCaD there were neutral mean J Ca(2+) and no changes in post-dialysis mean Ca2+ and PTHi plasma level s; furthermore 2 patients showed a small PTHi increase during HD with LCaD and neutral JCa(2+) because of a high positive bicarbonate balanc e during HD. In conclusion, as with several aspects of dialysis treatm ent, dialysate calcium levels should also be individualized to avoid h ypercalcemic crises or PTHi stimulation.