Sailing Between Scylla and Charybdis: The High Serum K-Low Dialysate K Quandary

In HD patients, the optimal choice of dialysate K concentration is of paramount importance. Recent large observational studies have documented an association between low dialysate K concentration (< 2 or even < 3 mEq/L) and a higher risk of sudden death. In this review, we first briefly discuss the available data concerning the link between hypokalemia and negative outcomes in non-CKD populations, especially after an acute myocardial infarction or in congestive heart failure. We next review the pathophysiology of the arrhythmogenic effect related to K fluxes during HD and discuss the dialytic strategies aiming at making potassium fall more gradual and thus at reducing the electrical disturbances triggered by the HD session. We conclude with practical recommendations regarding the optimal choice of K bath and the importance of more frequent monitoring of serum K in some clinical scenarios.