title: Unexpected haemodynamic instability associated with standard bicarbonate haemodialysis.
abstract: BACKGROUND
  The bicarbonate concentration in dialysis fluids for intermittent haemodialysis usually is between 32 and 35 mmol/l. The severity of chronic metabolic acidosis secondary to end-stage renal failure is very variable, however, so that in some patients pre-dialysis acidosis is overcorrected. This study aimed to analyse haemodynamic tolerances to metabolic alkalosis during intermittent haemodialysis.
  
  
  METHODS
  In this randomized controlled trial with a single blind, cross-over design, we used dialysis liquids with two different bicarbonate concentrations, 32 (modality A) and 26 (modality B) mmol/l, and in 26 patients, 468 dialysis sessions, compared blood pressure, heart rate, incidence of hypotension and the frequency of corrections required with saline or hypertonic glucose infusions.
  
  
  RESULTS
  The results of intradialytic haemodynamic monitoring for modalities A and B, respectively, were: lowest systolic blood pressure 120.8+/-20.8 vs 124.3+/-20.6 mmHg (P < 0.01); mean systolic blood pressure 138.5+/-23.8 vs 144.6+/-24.8 mmHg (P < 0.001); and highest heart rate 73.5+/-12.0 vs 75.8 +/- 12.9 (NS); with modality A, patients had more dialysis sessions with hypotensive episodes (5.55 vs 1.7%, P < 0.05) and required more saline or hypertonic glucose infusions (20.9 vs 13.7% of the dialysis sessions, P < 0.05).
  
  
  CONCLUSIONS
  Mild metabolic alkalosis resulting from standard bicarbonate haemodialysis (32 mmol/l) may induce symptomatic hypotension. While normalizing chronic metabolic acidosis is desirable, reducing bicarbonate concentrations should be considered in cases of significant alkalaemia or otherwise untreatable haemodynamic instability.
authors.affiliation: Department of Nephrology, Ospedale la Carità, Locarno, Switzerland. luca.gabutti@eoc.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Gabutti
authors.forename: Nicola
authors.initials: N
authors.lastname: Ferrari
authors.forename: Giacomo
authors.initials: G
authors.lastname: Giudici
authors.forename: Giorgio
authors.initials: G
authors.lastname: Mombelli
authors.forename: Claudio
authors.initials: C
authors.lastname: Marone
mesh_terms: D000328:Adult; D000368:Aged; D000471:Alkalosis / Q000139:chemically induced*; D001639:Bicarbonates / Q000009:adverse effects* / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D015312:Hemodialysis Solutions / Q000009:adverse effects* / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012720:Severity of Illness Index; D016037:Single-Blind Method
chemical_list: D001639:Bicarbonates; D015312:Hemodialysis Solutions