Calcium mass balances during standard bicarbonate hemodialysis and long-hour slow-flow bicarbonate hemodialysis.

Abstract

BACKGROUND:

Dialysate calcium (Ca) concentration should be viewed as part of the integrated therapeutic regimen to control renal osteodystrophy and maintain normal mineral metabolism. Thus, a correct ionized calcium mass balance (Ca++MB) during hemodialysis (HD) is crucial in the treatment of renal osteodystrophy. The GENIUS single-pass batch dialysis system (Fresenius Medical Care, Germany) consists of a closed dialysate tank of 90 L; it offers the opportunity of effecting mass balances of any solute in a very precise way.

METHODS:

The present study has a crossover design: 11 stable anuric HD patients underwent 2 bicarbonate HD sessions, 1 of 4 hours (4h) and the other of 8 hours (8h) in a random sequence, always at the same interdialytic interval, at least 1 week apart. The GENIUS system and high-flux FX80 dialyzers (Fresenius Medical Care, Germany) were used. The volume of blood and dialysate processed, volume of ultrafiltration and dialysate Ca concentrations (1.50 mmol/L) were prescribed to be the same. Trends of plasma Ca++, blood pH and bicarbonates during dialysis, as well as Ca++MBs were determined. Plasma parathyroid hormone (PTH) levels at the start and end of the 2 treatments were measured.

RESULTS:

Ca++MBs (mean ± SD) were +284.6 ± 137.4 mg and +297.7 ± 131.6 mg (p=0.307) in the 4h and 8h treatments, respectively. No single session out of the 22 had a negative Ca++MB for the patient. Mean plasma Ca++, blood pH and bicarbonate levels were not statistically significantly different when comparing the start and end of the sessions of the 2 treatments. Mean plasma Ca++, blood pH and bicarbonate levels increased significantly along the time points in both 4h and 8h HD sessions (repeated measures ANOVA: p<0.0001). Mean plasma PTH levels were not statistically significantly different when comparing the start and end of the sessions of the 2 treatments. The differences between predialysis and postdialysis plasma PTH levels were not statistically significantly different either in 4h or 8h sessions (Wilcoxon's test: p=NS), even though a trend toward lower postdialysis plasma PTH levels was observed in both 4h and 8h treatments.

CONCLUSIONS:

Our data show incontrovertibly that, when dialyzing with a dialysate Ca concentration of 1.50 mmol/L, 4h standard bicarbonate HD and 8h slow-flow bicarbonate HD always achieve a quite similar positive Ca++MB for the patients.

• Authors: Carlo Basile, Pasquale Libutti, Anna Lucia Di Turo, Sergio Tundo, Pasquale Maselli, Francesco Casucci, Nicola Losurdo, Annalisa Teutonico, Luigi Vernaglione, Carlo Lomonte
• Journal: Journal of nephrology (J Nephrol) 2011 Nov-Dec Vol. 24 Issue 6 Pg. 742-8 ISSN: 1724-6059 [Electronic] Italy
• PMID: 21360470 (Publication Type: Journal Article, Randomized Controlled Trial)

Chemical References

• Bicarbonates
• Hemodialysis Solutions
• Parathyroid Hormone
• Calcium

Topics

• Adult
• Aged
• Bicarbonates (pharmacokinetics)
• Calcium (metabolism)
• Chronic Kidney Disease-Mineral and Bone Disorder (etiology, prevention & control)
• Cross-Over Studies
• Female
• Hemodialysis Solutions
• Humans
• Hydrogen-Ion Concentration
• Male
• Middle Aged
• Parathyroid Hormone (blood)
• Renal Dialysis (methods)
• Renal Insufficiency (blood, complications, therapy)
• Time Factors
• Treatment Outcome