title: Hemodynamic behavior during hemodialysis: effects of dialysate concentrations of bicarbonate and potassium.
abstract: OBJECTIVE
  Ultrafiltration that occurs during hemodialysis (HD) promotes profound alterations in a relatively short period of time. The dialysate content of bicarbonate (DBic) and potassium (DK) may have impact over intradialytic hemodynamics, which goes beyond ultrafiltration, and its impact was evaluated in a prospective cohort.
  
  
  METHODS
  30 patients under HD were submitted to hemodynamic assessment (HA) at the beginning and at the end of HD sessions, through a non-invasive method. Serum minus dialysate potassium concentration was expressed as K-Gap. Cardiac index (CI) and peripheral arterial resistance (PAR) variation (post-HD minus pre-HD) were expressed as ΔCI and ΔPAR. Dialysate content of sodium and calcium were expressed as DNa and DCa, respectively.
  
  
  RESULTS
  Mean DNa, DK and DBic were, respectively, 136.4 ± 1.1, 2.1 ± 0.6 and 38.2 ± 2.1 mEq/L. In 15 patients, DCa was >1.5 mmol/L and in the other 15 patients ≤ 1.5 mmol/L. The K-Gap ranged from 1.4 to 5.1 mEq/l (median 3.0 mEq/L). There was a reduction in post-HD CI and systolic blood pressure (ΔCI = -0.72l/min/m(2) and -11.3±15.1mmHg, respectively, p<0.001 for both). Conversely, PAR increased (ΔPAR = 272dyn.s/cm(5), p<0.001). Lower post-HD CI was was associated to higher DBic (p=0.0013) and lower K-Gap (p=0.026). In multivariate analysis, ΔCI was dependent on DBic and K-Gap, whereas ΔPAR was dependent on dialysate calcium during HD.
  
  
  CONCLUSIONS
  We confirmed that Na and Ca dialysate content exerts and important role on hemodynamic during HD. In addition, our findings pointed out that higher dialysate concentrations of bicarbonate and potassium promote lower cardiac performance at the end of hemodialysis session.
authors.affiliation: Nephrology Division, University of São Paulo, School of Medicine, São Paulo, Brazil.
authors.forename: Bruno C
authors.initials: BC
authors.lastname: Silva
authors.forename: Geraldo R R
authors.initials: GR
authors.lastname: Freitas
authors.forename: Vitor B
authors.initials: VB
authors.lastname: Silva
authors.forename: Hugo
authors.initials: H
authors.lastname: Abensur
authors.forename: Claudio
authors.initials: C
authors.lastname: Luders
authors.forename: Benedito J
authors.initials: BJ
authors.lastname: Pereira
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: de Oliveira
authors.forename: Manuel C M
authors.initials: MC
authors.lastname: Castro
authors.forename: Rosa M A
authors.initials: RM
authors.lastname: Moysés
authors.forename: Rosilene M
authors.initials: RM
authors.lastname: Elias
mesh_terms: D000328:Adult; D001639:Bicarbonates / Q000008:administration & dosage* / Q000737:chemistry; D015314:Dialysis Solutions / Q000008:administration & dosage* / Q000737:chemistry; D005260:Female; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000008:administration & dosage* / Q000737:chemistry; D011446:Prospective Studies; D006435:Renal Dialysis / Q000379:methods*
chemical_list: D001639:Bicarbonates; D015314:Dialysis Solutions; D011188:Potassium