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

Abstract

Background Sudden death is frequent in haemodialysis (HD) patients. Both hyperkalaemia and change of plasma potassium (K) concentrations induced by HD could explain this. The impact of increasing dialysate K by 1 mEq/L on plasma K concentrations and electrocardiogram (ECG) results before and after HD sessions was studied. Methods Patients with pre-dialysis K >5.5 mEq/L were excluded. ECG and K measurements were obtained before and after the first session of the week for 2 weeks. Then, K in the dialysate was increased (from 1 or 3 to 2 or 4 mEq/L, respectively). Blood and ECG measurements were repeated after 2 weeks of this change. Results Twenty-seven prevalent HD patients were included. As expected, a significant decrease in K concentrations was observed after the dialysis session, but this decrease was significantly lower after the switch to an increased dialysate K. The pre-dialysis K concentrations were not different after changing, but post-dialysis K concentrations were higher after switching (P < 0.0001), with a lower incidence of post-dialysis hypokalaemia. Regarding ECG, before switching, the QT interval (QT) dispersion increased during the session, whereas no difference was observed after switching. One week after switching, post-dialysis QT dispersion [38 (34–42) ms] was lower than post-dialysis QT dispersion 2 weeks and 1 week before switching [42 (38–57) ms, P = 0.0004; and 40 (35–50) ms, P = 0.0002]. Conclusions A simple increase of 1 mEq/L of K in the dialysate is associated with a lower risk of hypokalaemia and a lower QT dispersion after the dialysis session. Further study is needed to determine if such a strategy is associated with a lower risk of sudden death.

Correlation between lactate dehydrogenase and QTc interval prolongation in maintenance hemodialysis patients: a cross-sectional study

“…Low K low Ca, and low P are recognized risk factors for QTc interval prolongation (4,14). During hemodialysis, a rapid drop in serum calcium or potassium can lead to a prolongation of the QTc interval and an increase in QTc dispersion (15)(16)(17)(18). In this study, there were similar results.…”

The prevalence of predialysis hyperkalemia and associated characteristics among hemodialysis patients: The RE‐UTILIZE study

“…In addition, higher predialysis K + concentrations are associated with greater acute reductions in serum K + during and immediately after HD, 7 which may increase the risk of cardiac arrhythmia. 8 The reported prevalence of HK in patients on HD has varied between epidemiologic studies from different regions, including the United States (US) and Europe. 2,[9][10][11] Some of the variations may be due to differences in measured durations (e.g., monthly vs. annual prevalence), threshold laboratory K + values (e.g., >5.0 vs. >5.5 vs. >6.0 mEq/L), or number of laboratory K + values used to define HK (e.g., one vs. two).…”

“…Predialysis serum K + concentrations of ≥5.5, 4 ≥5.6, 5 and ≥5.7 mEq/L 1 have been associated with an increased risk of all‐cause mortality. In addition, higher predialysis K + concentrations are associated with greater acute reductions in serum K + during and immediately after HD, 7 which may increase the risk of cardiac arrhythmia 8 …”

QT-Prolonging Antibiotics, Serum-to-Dialysate Potassium Gradient, and Risk of Sudden Cardiac Death Among Patients Receiving Maintenance Hemodialysis

“…The amount of intradialytic potassium removal is driven by the magnitude of the serum-to-dialysate gradient; a larger difference between serum potassium and prescribed dialysate potassium concentration results in a larger gradient and greater intradialytic potassium removal. 3 , 4 , 5 Exposure to large potassium gradients has been linked to electrocardiographic risk markers for cardiac arrest, including QT interval prolongation 6 , 7 , 8 , 9 , 10 and QT dispersion, 6 , 11 , 12 , 13 and is associated with higher risks of hospitalization and mortality. 14 , 15 …”