title: Haemodynamic consequences of changing potassium concentrations in haemodialysis fluids.
abstract: BACKGROUND
  A rapid decrease of serum potassium concentrations during haemodialysis produces a significant increase in blood pressure parameters at the end of the session, even if effects on intra-dialysis pressure are not seen. Paradoxically, in animal models potassium is a vasodilator and decreases myocardial contractility. The purpose of this trial is to study the precise haemodynamic consequences induced by acute changes in potassium concentration during haemodialysis.
  
  
  METHODS
  In 24 patients, 288 dialysis sessions, using a randomised single blind crossover design, we compared six dialysate sequences with different potassium profiles. The dialysis sessions were divided into 3 tertiles, casually modulating potassium concentration in the dialysate between the value normally used K and the two cut-off points K+1 and K-1 mmol/l. Haemodynamics were evaluated in a non-invasive manner using a finger beat-to-beat monitor.
  
  
  RESULTS
  Comparing K-1 and K+1, differences were found within the tertiles regarding systolic (+5.3, +6.6, +2.3 mmHg, p < 0.05, < 0.05, ns) and mean blood pressure (+4.3, +6.4, -0.5 mmHg, p < 0.01, < 0.01, ns), as well as peripheral resistance (+212, +253, -4 dyne.sec.cm-5, p < 0.05, < 0.05, ns). The stroke volume showed a non-statistically-significant inverse trend (-3.1, -5.2, -0.2 ml). 18 hypotension episodes were recorded during the course of the study. 72% with K-1, 11% with K and 17% with K+1 (p < 0.01 for comparison K-1 vs. K and K-1 vs. K+1).
  
  
  CONCLUSIONS
  A rapid decrease in the concentration of serum potassium during the initial stage of the dialysis-obtained by reducing the concentration of potassium in the dialysate-translated into a decrease of systolic and mean blood pressure mediated by a decrease in peripheral resistance. The risk of intra-dialysis hypotension inversely correlates to the potassium concentration in the dialysate.
  
  
  BACKGROUND
  NCT01224314.
authors.affiliation: Division of Nephrology, Ospedale Carità, Via Ospedale, 6600 Locarno, Switzerland. luca.gabutti@eoc.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Gabutti
authors.forename: Igor
authors.initials: I
authors.lastname: Salvadé
authors.forename: Barbara
authors.initials: B
authors.lastname: Lucchini
authors.forename: Davide
authors.initials: D
authors.lastname: Soldini
authors.forename: Michel
authors.initials: M
authors.lastname: Burnier
mesh_terms: D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D005260:Female; D015312:Hemodialysis Solutions / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007022:Hypotension / Q000503:physiopathology*; D008297:Male; D011188:Potassium / Q000097:blood* / Q000494:pharmacology; D006435:Renal Dialysis / Q000379:methods*; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D015312:Hemodialysis Solutions; D011188:Potassium