Low Dialysate Potassium Concentration: An Overrated Risk Factor for Cardiac Arrhythmia?

Abstract

Serum potassium concentrations rise with dietary potassium intake between dialysis sessions and are often at hyperkalemic levels by the next session. Conversely, potassium concentrations fall during each hemodialysis, and sometimes reach hypokalemic levels by the end. Low potassium dialysate, which rapidly decreases serum potassium and often brings it to hypokalemic levels, is almost universally considered a risk factor for life-threatening arrhythmias. While there is little doubt about the threat of lethal arrhythmias due to hyperkalemia, convincing evidence for the danger of low potassium dialysate and rapid or excess potassium removal has not been forthcoming. The original report of more frequent ventricular ectopy in early dialysis that was improved by reducing potassium removal has received very little confirmation from subsequent studies. Furthermore, the occurrence of ventricular ectopy during dialysis does not appear to predict mortality. Studies relating sudden deaths to low potassium dialysate are countered by studies with more thorough adjustment for markers of poor health. Dialysate potassium concentrations affect the excursions of serum potassium levels above or below the normal range, and have the potential to influence dialysis safety. Controlled studies of different dialysate potassium concentration and their effect on mortality and cardiac arrests have not been done. Until these results become available, I propose interim guidelines for the setting of dialysate potassium levels that may better balance risks and benefits.

Identification of 22 novel loci associated with urinary biomarkers of albumin, sodium, and potassium excretion

“…Both low blood potassium levels (hypokalemia) and high blood potassium levels (hyperkalemia) can lead to abnormal heart rhythms. 45 We observed colocalization of the GWAS signal for UACR and UK/UCr in the GATM locus with mQTL signals. The GATM locus is not novel in terms of association with renal function, as previous studies have shown its association with CKD and reduced glomerular filtration rate.…”

Mechanisms, Clinical Implications, and Treatment of Intradialytic Hypotension

“…The effects of dialysate potassium concentration are less clear. Although interventions that reduce the rapidity of potassium changes during hemodialysis have been shown to reduce the risk of premature ventricular complexes (33), others have questioned the broader clinical effect of serum and dialysate potassium gradients (34). Finally, magnesium appears to play an important role in maintaining myocardial electrical stability and regulating vascular smooth muscle tone.…”

Acquired long QT syndrome in chronic kidney disease patients

“…Low potassium can be caused by low dietary potassium intake, malnutrition, chronic diarrhea, or the use of prescription drugs [77]. Furthermore, with the use of a low potassium dialysate, K þ is removed mainly from the extracellular space and only slightly from the intracellular space; thus, the extracellular potassium level decreases too abruptly, and the intracellular/extracellular potassium ratio increases rapidly [78].…”