Does bicarbonate transfer have relevant hemodynamic consequences in standard hemodialysis?

Blood Purif. 2005;23(5):365-72. doi: 10.1159/000087193. Epub 2005 Jul 27.


Background: In a previous study we demonstrated that mild metabolic alkalosis resulting from standard bicarbonate hemodialysis induces hypotension. This study aimed to compare hemodynamic consequences of either a decrease in the dialysate bicarbonate from 32 to 26 mmol/l or an increase in the dialysate calcium of 0.25 mmol/l and to verify whether the calcium shift secondary to alkalemia explains the consequences on blood pressure.

Methods: In this randomized controlled trial with a single-blind, cross-over design, we used dialysis liquids with two different bicarbonate (32 mmol/l in modalities A and C, and 26 mmol/l in modality B) and calcium (1.25 mmol/l in modalities A and B, and 1.50 mmol/l in modality C) concentrations, and in 27 patients, 243 dialysis sessions, compared blood pressure, heart rate and the incidence of hypotension.

Results: No significant differences were seen between A and B while an increase in systolic and diastolic blood pressures and a decrease in the incidence of hypotension (10.5 vs. 1.2%, p < 0.05) were documented in C. The subgroup of patients who with A showed a lower mean systolic blood pressure received more angiotensin-converting enzyme inhibitors or angiotensin II type-1 receptor blockers (36 vs. 0%, p<0.05) and in C showed a less important increase in systolic and diastolic pressures, but the incidence of hypotensive episodes between A and B was not significantly different (9.1 vs. 15.1%).

Conclusions: In the present study it was not possible to demonstrate hemo dynamic instability associated with mild metabolic alkalosis. Even in the subgroup showing a lower blood pressure with a higher dialysate bicarbonate, significant hemodynamic or clinical consequences were not noticed. The calcium shift (0.05 mmol/l) related to alkalemia would justify a mean decrease in systolic blood pressure of only about 1 mm Hg.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alkalosis / chemically induced
  • Bicarbonates / pharmacology*
  • Blood Pressure
  • Calcium / pharmacology
  • Female
  • Heart Rate
  • Hemodialysis Solutions / chemistry
  • Hemodialysis Solutions / pharmacology
  • Hemodynamics / drug effects*
  • Humans
  • Hypotension / chemically induced
  • Male
  • Middle Aged
  • Renal Dialysis / methods*


  • Bicarbonates
  • Hemodialysis Solutions
  • Calcium