Abstract
Better correction of metabolic acidosis is achieved by bicarbonate dialysis (BiHD) than acetate dialysis (AcHD). Metabolic acidosis may contribute to hyperphosphatemia through the release of intracellular phosphate. Therefore, we studied whether serum phosphorus (P) levels in BiHD are lower than in AcHD. We also evaluated the relation betewwn P level and plasma HCO3- level. Data were obtained from 14 chronic HD patients switched from AcHD to BiHD (Ac-BiHD group) and from 12 chronic HD patients given oral NaHCO3 therapy (oral NaHCO3 group). All dialysis programs execept dialysate buffer in the Ac-BiHD group and all medications except oral NaHCO3 in the oral NaHCO3 group remained unchanged throughout the study. Four routine biochemical measurements during 8 weeks were averaged to give a mean representation of the patients' data, and the mean values were compared before and after changing dialysate buffer or instituting oral NaHCO3 therapy.
After shifting to BiHD in the Ac-BiHD group, the pre-dialysis serum P level decreased significantly (5.4±1.0 vs 4.8±1.0mg/dl, p<0.01), and post-dialysis plasma HCO3- level increased significantly. After oral NaHCO3- therapy in the oral NaHCO3 group, pre-dialysis serum P level decreased significantly (5.6±1.0 vs 5.0±1.0mg/dl, p<0.05), and plasma HCO3- level increased significantly. There was a significant inverse correlation between serum P and plasma HCO3- in 6 of 13 patients. These results indicate that the decresed serum P level in BiHD is due to better control of metabolic acidosis. In conclusion, BiHD is more helpful than AcHD in controlling serum P, preventing secondary hyperparathyroidism and minimizing the risk of aluminum intoxication.
