Calcium and magnesium mass transfer in peritoneal dialysis patients using 1.25 mmol/L calcium, 0.25 mmol/L magnesium dialysis fluid.
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.


METHODS
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 0 and 240 minutes.


METHODS
Single renal unit of a university teaching hospital.


METHODS
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.
Hutchison
A J
AJ
Manchester Royal Infirmary Renal Unit, United Kingdom.
Merchant
M
M
Boulton
H F
HF
Hinchcliffe
R
R
Gokal
R
R
D000328:Adult; D000368:Aged; D002118:Calcium / Q000378:metabolism*; D015314:Dialysis Solutions / Q000737:chemistry*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory
D015314:Dialysis Solutions; D008274:Magnesium; D002118:Calcium