Tailoring the dialysate bicarbonate eliminates pre-dialysis acidosis and post-dialysis alkalosis

Abstract

Background Both metabolic acidosis and alkalosis increase hospitalizations, hemodynamic instability, and mortality of hemodialysis patients. Unfortunately, current practices opt for a one-size-fits-all approach, leaving many patients either acidotic before or alkalotic after dialysis sessions. Therefore, an individualized adjustment of these patients’ dialysate bicarbonate prescriptions could reduce these acid-base imbalances. Methods This is a prospective single-cohort study of patients on chronic hemodiafiltration program. The dialysate bicarbonate prescription was modified according to the pre- and post-dialysis TCO2 values of 19 and 25 mEq/L and ≤ 29 mEq/L, respectively, with an adjustment formula calculated with the data obtained from previously published work by our group. In addition, we analyzed this adjustment's effect on plasma sodium, potassium, phosphorus, PTH, and calcium. Results At baseline, only 67.9% of patients were within the desired pre- and post-dialysis TCO2 target range. As of the first month, every followed patient met the TCO2 target range objective in pre-dialysis measurements, and more than 95% met the post-dialysis TCO2 target. At the end of the study, 75% of the patients were on dialysate bicarbonate of 32 – 34 mEq/L. There were no clinically significant changes in calcium, phosphate, PTH, sodium, or potassium levels. Also, we did not notice any increase in intradialytic adverse events. Conclusions We suggest an individualized adjustment of the dialysate bicarbonate concentration according to the pre- and post-dialysis TCO2 values. With it, nearly every patient in our cohort reached the established range, potentially reducing their mortality risk.

Hemodynamic effects of low versus high dialysate bicarbonate concentration in hemodialysis patients

“…Two small-scale single center studies with a relatively short follow-up of 6 months employed this approach. 26,27 Dialysate bicarbonate was modified according to the preand post-dialysis total carbon dioxide values in these studies. Yet, although lowering of dialysate bicarbonate was safe in terms of intradialytic adverse events these studies were not powered for hard endpoints such as mortality and cardiovascular events.…”

“…The UK renal dialysis guideline suggest a dialysate bicarbonate below or equal to 37 mmol/L with a pre‐dialysis serum bicarbonate target of 18–26 mmol/L 2 . Two small‐scale single center studies with a relatively short follow‐up of 6 months employed this approach 26,27 . Dialysate bicarbonate was modified according to the pre‐ and post‐dialysis total carbon dioxide values in these studies.…”

“…Our study supports previous recommendations regarding a preferable effect of lowering dialysate bicarbonate below 35 mmol/L 2 . [25][26][27] High dialysate bicarbonate treatment was associated with marked metabolic alkalosis, hypocalcemia, lower plasma potassium and possible hemodynamic instability that potentially could contribute negatively to patient discomfort, morbidity, and mortality. In our view, dialysate bicarbonate in the region of 32-35 mmol/L is probably optimal for most patients and a higher concentration should generally be avoided.…”