Dialysate potassium concentration: Should mass balance trump electrophysiology?

Abstract

Nephrologists are faced with a difficult dilemma in choosing the ideal dialysis prescription to maintain neutral potassium mass balance. Should potassium mass balance goals prioritize the normalization of serum potassium levels using low potassium dialysate at the expense of provoking intradialytic arrhythmias, or should mass balance goals favor permissive hyperkalemia using higher dialysate potassium to avoid rapid intradialytic fluxes at the risk of more interdialytic arrhythmias? This review examines the factors that determine potassium mass balance among HD patients, the relationships between serum and dialysate potassium levels and outcomes, and concludes by examining currently available approaches to reducing risk of arrhythmias while managing potassium mass balance.

A simple modification of dialysate potassium: its impact on plasma potassium concentrations and the electrocardiogram

“…As expected, we found that dialysis sessions caused a significant decrease of plasma K concentrations. The increase in dialysate K was associated with a lesser decrease in plasma K concentrations [ 12 , 13 , 28 , 30 , 42–46 ], and accordingly with a much lower prevalence of post-dialysis hypokalaemia, including severe hypokalaemia (plasma K <3.0 mEq/L in 6 versus 38% of cases). The higher post-dialysis K concentrations observed with higher dialysate K was accompanied by only a modest and non-significant increase in pre-dialysis plasma K concentrations (and a non-significant higher prevalence of hyperkalaemia).…”

“…Hyperkalaemia before dialysis session is frequent, dangerous and increases morbidity and mortality [ 7 , 17 , 18 , 22–30 ]. Additional data also suggest that pre-dialysis hypokalaemia, although less frequent, could be associated with higher mortality [ 11 , 13 , 22 , 25 , 27 , 30–32 ]. The risk of post-dialysis hypokalaemia is much less well studied and thus its prevalence is not precisely known [ 11 , 31 , 33 ].…”

“…In addition, there may be a higher risk of mortality and sudden death in dialysis patients treated with low dialysate K [ 4 , 8 , 9 , 12–15 , 17 , 18 , 25 , 28–30 , 36 , 37 ]. These observations suggest the utility of switching from low K dialysate to higher K dialysate [ 4 , 12 , 13 , 15 , 18 , 22 , 28 , 30 ]. However, most data supporting this hypothesis are derived from purely observational cohorts.…”

“…However, most data supporting this hypothesis are derived from purely observational cohorts. Moreover, results from observational studies comparing mortality according to K dialysate are not uniform, and some authors showed no association between low K dialysate and mortality [ 17 , 24 , 30 , 36 , 38 , 39 ]. A recent observational Japanese study showed significant association between post-dialysis K concentration and mortality, but the association was lost after adjustment for pre-dialysis K concentration [ 31 ].…”

Introduction to treatment considerations in conventional hemodialysis ‐ What we know

“…As new technologies allow greater opportunities to alter dialysate constituents, dialysate prescription has also been evolving. On the topic of dialysate potassium concentration, Pun reviews the currently available approaches for managing potassium mass balance while reducing risk of arrhythmias by examining the factors that determine potassium mass balance and assessing the relationship between serum and dialysate potassium levels and outcomes …”