Calcium and Magnesium Mass Transfer in Peritoneal Dialysis Patients Using 1.25 Mmol/L Calcium, 0.25 Mmol/L Magnesium Dialysis Fluid

Abstract

Objective To examine the effect of a reduced calcium/magnesium dialysis fluid (1.25/0.25 mmol/L, respectively) on calcium and magnesium mass transfer in both 1.36% and 3.86% glucose solutions. Design Each patient underwent four test exchanges, two with a standard dialysis fluid containing 1.36% and 3.86% glucose, and two with a reduced calcium/magnesium fluid containing 1.36% and 3.86% glucose. Calcium and magnesium were measured in dialysate and serum at ° and 240 minutes. Setting Single renal unit of a university teaching hospital. Patients Sixteen patients established on CAPD, and peritonitis-free, for at least 3 months. Results A lower dialysate calcium results in negative mass transfer when serum-ionized calcium exceeds dialysate calcium (mean -.0.21±0.15 mmol/exchange), and positive mass transfer when serum-ionized calcium is less than dialysate calcium in 1.36% glucose solutions (mean 0.57±0.18 mmol/exchange). A negative correlation was found between serum-ionized calcium level and calcium mass transfer. With a 3.86% reduced calcium/magnesium solution, calcium mass transfer is always negative (-.0.88±0.18 mmol/exchange) due to ultrafiltration and solute drag. Fifteen patients were found to be hypermagnesemic at the time of the study. Magnesium mass transfer was neutral with the standard 1.36% glucose fluid (mean -.0.01 mmol/exchange), but negative with the reduced calcium/magnesium 1.36% glucose fluid (mean -.0.58±0.13 mmol/exchange). With the 3.86% glucose solution, both fluids produced negative magnesium mass transfer (mean -.0.32±0.11 and -1.07±0.11 mmol/exchange for standard and reduced calcium/magnesium fluids, respectively). Conclusions We conclude that this fluid formulation should reduce hypercalcemia and hypermagnesemia in CAPD patients.

Long‐term effects of intermittent oral alphacalcidol, calcium carbonate and low‐calcium dialysis (1.25 mmol L−1) on secondary hyperparathyroidism in patients on continuous ambulatory peritoneal dialysis

“…As seen in earlier studies [ 24–28], the present study demonstrated a change from a positive to a negative calcium MT, when the calcium concentration in the dialysate was reduced from 1.75 to 1.25 mmol L −1 ( Fig. 4).…”

Magnesium in chronic kidney disease Stages 3 and 4 and in dialysis patients

“…For many years, PD solutions with a magnesium concentration of 0.75 mmol/L and calcium concentration of 1.75 mmol/L were used as ‘standard’ dialysate for the majority of patients although there has been a trend to lower dialysate calcium over the past decade. Patients using these solutions are slightly hypermagnesaemic [ 37 , 39 , 40 ] (see Table 1 ). This is because the transfer of magnesium is, if diffusive, mostly into the patient and thus positive [ 39 , 41 ].…”

“…In contrast, when patients are treated with a low magnesium dialysate (0.25 mmol/L), serum magnesium levels normalize after some time, as dialytic magnesium balance is constantly negative, independent of glucose concentration, use of icodextrin (i.e. ultrafiltration) or treatment modality (continuous ambulatory PD or automated PD) [ 40 – 42 ] ( Table 1 ).…”

Oral Phosphate Binders for the Management of Serum Phosphate Levels in Dialysis Patients

“…Magnesium is predominantly an intracellular cation with an important role in cellular physiology. Serum levels are often slightly elevated in dialysis patients (Nilsson et al 1984) and are influenced by the concentration of dialysate magnesium (Hutchison et al 1993;Hutchison et al 1996). Retrospective studies suggest that magnesium may prevent vascular calcification in dialysis patients, although this remains controversial and has not been evaluated prospectively (Meema et al 1987).…”