Haemodynamic consequences of changing potassium concentrations in haemodialysis fluids

Abstract

BackgroundA 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.MethodsIn 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.ResultsComparing 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).ConclusionsA 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.Trial Registration NumberNCT01224314

Dialysate Potassium, Serum Potassium, Mortality, and Arrhythmia Events in Hemodialysis: Results From the Dialysis Outcomes and Practice Patterns Study (DOPPS)

“…This may be especially problematic in cases where the DK administered during the treatment directly preceding an arrhythmic event differed from the standing prescription. Similarly, DK profiling, the varying of DK during a single HD session, 31,32,34 was not captured in the DOPPS and thus we cannot calculate its prevalence nor speculate on its effect on clinical outcomes.…”

Parathyroidectomized patients have impaired capacity of peripheral vascular constriction during hemodialysis

“…One can argue that Finometer is not a well‐validated method to access hemodynamic changes during dialysis. However, it should be pointed out that this device has already been tested against intra‐arterial BP in hypertensive patients and has also been cited in several publications on dialysis patients with consistent results . In fact, one study found that the absolute cardiac output values reported by Finometer were unreliable .…”

Plasma and dialysate potassium concentrations and haemodialysis associated mortality

“…Whatever the risk of death of using a low dialysate potassium, it does have cardiac and hemodynamic consequences which place the patient risk. In a blinded crossover study of 24 patients with variations in dialysate potassium, the lower potassium lead to a lower mean blood pressure and a decrease in peripheral resistance . In another crossover study of 42 people on dialysis a larger gradient between plasma and dialysate potassium early in dialysis was associated with an increased frequency of premature ventricular contractions, and their coupling …”