title: Effect of dialysate calcium concentrations on parathyroid hormone and calcium balance during a single dialysis session using bicarbonate hemodialysis: a crossover clinical trial.
abstract: BACKGROUND
  In bicarbonate-based hemodialysis, dialysate total calcium (tCa) concentration may have effects on mineral metabolism.
  
  
  METHODS
  Randomized crossover trial of 3 dialysate tCa concentrations (2.5, 2.75, and 3.0 mEq/L).
  
  
  METHODS
  22 stable anuric uremic patients underwent three 4-hour bicarbonate hemodialysis sessions with the 3 different dialysate tCa concentrations using a single-pass batch dialysis system.
  
  
  RESULTS
  Hourly measurements of plasma water ionized calcium (iCa) and plasma parathyroid hormone (PTH) concentrations. tCa mass balances were measured from the dialysate side.
  
  
  RESULTS
  Hourly plasma water iCa concentrations were higher with a dialysate tCa concentration of 3.0 compared with 2.75 and 2.5 mEq/L (P < 0.05), as were iCa concentrations at the end of dialysis sessions (2.66 ± 0.1, 2.56 ± 0.12, and 2.4 ± 0.08 mEq/L, respectively; P < 0.001). Mean tCa mass balance values (diffusion gradient from the dialysate to the patient) were positive with all dialysate tCa concentrations and increased progressively with dialysate tCa concentration (75 ± 122, 182 ± 125, and 293 ± 228 mg, respectively; P < 0.001). Plasma PTH levels increased during dialysis using dialysate tCa concentration of 2.5 mEq/L (mean increase, 225 ± 312 pg/mL) and decreased with dialysate tCa concentrations of 2.75 and 3.0 mEq/L (mean decreases, 68 ± 325 and 99 ± 432 pg/mL, respectively).
  
  
  CONCLUSIONS
  Small sample size and lack of measurement of total-body calcium mass balances.
  
  
  CONCLUSIONS
  A dialysate tCa concentration of 2.75 mEq/L might be preferable to 2.5 or 3.0 mEq/L because it is associated with mildly positive tCa mass balance values, plasma water iCa levels in the reference range, and stable PTH levels during dialysis.
authors: Nephrology and Dialysis Unit, Miulli General Hospital, Acquaviva delle Fonti, Italy. basile.miulli@libero.it
authors: Carlo
authors: C
authors: Basile
authors: Pasquale
authors: P
authors: Libutti
authors: Anna Lucia
authors: AL
authors: Di Turo
authors: Luigi
authors: L
authors: Vernaglione
authors: Francesco
authors: F
authors: Casucci
authors: Nicola
authors: N
authors: Losurdo
authors: Annalisa
authors: A
authors: Teutonico
authors: Carlo
authors: C
authors: Lomonte
mesh_terms: D001639:Bicarbonates / Q000008:administration & dosage*; D002118:Calcium / Q000032:analysis* / Q000097:blood; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis
chemical_list: D001639:Bicarbonates; D015314:Dialysis Solutions; D010281:Parathyroid Hormone; D002118:Calcium