Intradialytic acid-base changes and organic anion production during high versus low bicarbonate hemodialysis

Sarah Park, William Paredes, Matthew Custodio, Narender Goel, Deepak Sapkota, Anusha Bandla, Robert I. Lynn, Suman M. Reddy, Thomas H. Hostetter, Matthew K. Abramowitz

Research output: Contribution to journalArticle

Abstract

The use of high dialysate bicarbonate for hemodialysis in end-stage renal disease is associated with increased mortality, but potential physiological mediators are poorly understood. Alkalinization due to high dialysate bicarbonate may stimulate organic acid generation, which could lead to poor outcomes. Using measurements of β-hydroxybutyrate (BHB) and lactate, we quantified organic anion (OA) balance in two single-arm studies comparing high and low bicarbonate prescriptions. In study 1 (n = 10), patients became alkalemic using 37 meq/L dialysate bicarbonate; in contrast, with the use of 27 meq/L dialysate, net bicarbonate loss occurred and blood bicarbonate decreased. Total OA losses were not higher with 37 meq/L dialysate bicarbonate (50.9 vs. 49.1 meq using 27 meq/L, P = 0.66); serum BHB increased in both treatments similarly (P = 0.27); and blood lactate was only slightly higher with the use of 37 meq/L dialysate (P = 0.048), differing by 0.2 meq/L at the end of hemodialysis. In study 2 (n = 7), patients achieved steady state on two bicarbonate prescriptions: they were significantly more acidemic when dialyzed against a 30 meq/L bicarbonate dialysate compared with 35 meq/L and, as in study 1, became alkalemic when dialyzed against the higher bicarbonate dialysate. OA losses were similar to those in study 1 and again did not differ between treatments (38.9 vs. 43.5 meq, P = 0.42). Finally, free fatty acid levels increased throughout hemodialysis and correlated with the change in serum BHB (r = 0.81, P < 0.001), implicating upregulation of lipolysis as the mechanism for increased ketone production. In conclusion, lowering dialysate bicarbonate does not meaningfully reduce organic acid generation during hemodialysis or modify organic anion losses into dialysate.

Original languageEnglish (US)
Pages (from-to)F1418-F1429
JournalAmerican Journal of Physiology - Renal Physiology
Volume318
Issue number6
DOIs
StatePublished - Jun 2020

Keywords

  • Bicarbonate
  • Hemodialysis
  • Ketones
  • Lipolysis
  • Organic anion

ASJC Scopus subject areas

  • Physiology
  • Urology

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