This study aimed to assess the effects of different
dialysate bicarbonate concentrations in correcting
acid-base imbalance in 53 stable
hemodialysis patients in a university-
hemodialysis unit. Three different
bicarbonate concentrations were assigned, i.e. 25 mEq/L in 10, 30 mEq/L in 30, and 35 mEq/L in 13 patients. Blood gas analyses from
arterial line blood samples before and after dialysis in the mid-week were performed for the determination of pH and serum
bicarbonate (HCO3 (-)) concentration. The mean values of predialysis arterial HCO3 (-) were mildly acidotic in all 3 groups, but not significantly different among them, whereas those of post-dialysis arterial HCO3 (-) were alkalotic, especially in the group of 35 mEq/L as compared with the other two groups. The mean blood pH was not significantly different among the 3 groups. As expected, there was a positive correlation between pre-dialysis pH and post-dialysis pH (r=0.45, p=0.001), and pre-dialysis HCO3 (-) and post-dialysis HCO3 (-) (r=0.58, p=0.000), but with a negative correlation between pre-dialysis HCO3 (-) and the increment of intradialytic HCO3 (-) following
hemodialysis (r=-0.46, p=0.001). In conclusion, this study shows that the impact of conventional
dialysate bicarbonate concentrations ranging from 25 to 35 mEq/L is not quite different on the mild degree of predialysis acidemia, but the degree of postdialysis alkalemia is more prominent in higher
bicarbonate concentrations. Base supply by
hemodialysis alone does not seem to be the main factor to determine the predialysis
acidosis in
end-stage renal disease patients on chronic maintenance
hemodialysis.