Amount of Magnesium Removed during Predilution Online Hemodiafiltration Compared to Conventional Hemodialysis

Aim: The aim of the study was to investigate how much magnesium is removed with predilution online hemodiafiltration (with or without glucose in dialysate), compared to conventional hemodialysis. Patients-Methods: The amount of magnesium removed during different dialysis methods (by collecting all the ultrafiltrate in a volumetric barrel) was studied in 27 dialyzed patients, aged 53 - 92 (mean ± SD = 72.0 ± 11.5, median = 73 years), who were on a dialysis program from 12 to 450 months (92.6 ± 91.6 months). In the first group (Group A), with predilution online hemodiafiltration the dialysate had glucose, in the second also with predilution online hemodiafiltration with the same composition of dialysate but without glucose (Group B) and in the third conventional hemodialysis was used (Group C). We determined serum urea and magnesium before and after the end of each session, as well as the volume of the total ultrafiltrate, as well as its urea and magnesium content. Everyone had one session under the conditions mentioned, which were one week apart. Results: Regarding magnesium removal, no significant difference was found with predilution online hemodiafiltration (with and without glucose in dialysate), compared to conventional hemodialysis (p = NS in both cases). The only side effect recorded was hypoglycemia in 3 patients during sessions with glucose-free dialysate, which were treated with intravenous administration of 35% dextrose solution. Conclusion: It is concluded that the amount of magnesium removed is not affected by the method of dialysis (predilution online HDF and conventional hemodialysis), nor from the dialysate used (with or without glucose) or the kind of dialyzer (low or high flux), despite the same clearance given for small molecules (Kt/V and URR).