Sailing between Scylla and Charybdis: the high serum K-low dialysate K quandary

Effect of banana intake on serum potassium level in patients undergoing maintenance hemodialysis: A randomized controlled trial

Objective

This study aimed to assess the effect of banana intake during hemodialysis on serum potassium levels in maintenance hemodialysis (MHD) patients.

Methods

This study was a single-center, randomized controlled clinical trial conducted from September 15 to December 15, 2021, at a tertiary hospital in southern China. A total of 126 MHD patients were randomly assigned to either the intervention group (n = 64) or the control group (n = 62). Patients in the intervention group consumed approximately 250 g of bananas during hemodialysis, while those in the control group did not consume any food during hemodialysis. Demographic information and hemodialysis-related parameters were collected through case information collection before hemodialysis. Laboratory indicators (such as complete blood count, biochemical indicators, inflammation markers, liver function, kidney function, etc.) were evaluated by collecting pre-hemodialysis blood samples from patients. Serum potassium and blood glucose levels were measured at 2 h and 4 h of hemodialysis, as well as before the next hemodialysis session, and hemodialysis-related complications were recorded. The blood potassium and blood glucose indicators during hemodialysis were compared using repeated measures analysis.

Results

A total of 122 MHD patients completed the study (61 in each group). The results showed that there was no significant interaction between group and time on serum potassium levels. However, serum potassium levels in the intervention group were higher than those in the control group at 2 h (3.9 ± 0.5 mmol/L vs. 3.6 ± 0.3 mmol/L, P < 0.01) and 4 h (3.5 ± 0.4 mmol/L vs. 3.3 ± 0.3 mmol/L, P < 0.01) of hemodialysis. There was no interaction between group and time on blood glucose levels. The incidence of arrhythmias (8.2% vs. 29.5%, P = 0.003) and hypokalemia (52.5% vs. 80.3%, P = 0.002) during hemodialysis was significantly lower in the intervention group compared to the control group.

Conclusion

Consuming approximately 250 g of bananas at the start of hemodialysis does not lead to hyperkalemia. It can effectively reduce the incidence of hypokalemia and arrhythmias, and prevent a rapid decline in serum potassium levels during hemodialysis.

Hyperkalaemia prevalence, recurrence and treatment in patients on haemodialysis in China: protocol for a prospective multicentre cohort study (PRECEDE-K)

INTRODUCTION

Hyperkalaemia (HK) is a potentially life-threatening electrolyte imbalance associated with several adverse clinical outcomes and is common in patients with kidney failure. However, there is no evidence on the occurrence, recurrence and treatment of HK in patients on haemodialysis (HD) in China.

METHODS AND ANALYSIS

The HK Prevalence, Recurrence, and Treatment in Haemodialysis Study is a prospective, multicentre, observational, cohort study being conducted across 15-18 sites in China. Approximately 600 patients with end-stage kidney disease on HD are anticipated to be enrolled and will be followed up for 24 weeks. Patients will be in the long interdialytic interval (LIDI) at enrolment and will receive follow-up care every 4 weeks in LIDI for pre-dialysis and post-dialysis (at enrolment only) serum potassium measurements. To obtain pre-dialysis serum potassium levels in the short interdialytic interval (SIDI), a follow-up visit will be performed in the SIDI during the first week. Information on concomitant medications, blood gas analysis and biochemistry measurements will be obtained at enrolment and at each follow-up visit. The primary endpoint will be the proportion of patients experiencing HK (defined as serum potassium level >5.0 mmol/L) at the study enrolment or during the 24-week follow-up. The key secondary endpoint will be the proportion of patients experiencing HK recurrence (defined as any HK event after the first HK event) within 1-6 months (if applicable) during the 24-week follow-up, including enrolment assessment.

ETHICS AND DISSEMINATION

This study has been approved by Shanghai Jiaotong University School of Medicine, Renji Hospital Ethics Committee (2020-040). Other participating subcentres must also obtain ethics committee approval prior to the start of the study. The Good Clinical Practice regulations shall be strictly followed during the test implementation. Amendments to the protocol will be reviewed by the ethics committees. Written informed consent will be obtained from all participants before collection of any patient data and patient information. The findings of this study will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04799067).

Hemodialysis treatment in patients with severe electrolyte disorders: Management of hyperkalemia and hyponatremia

Significant deviations of serum potassium and sodium levels are frequently observed in hospitalized patients and are both associated with increased all‐cause and cardiovascular mortality. The presence of acute or chronic renal failure facilitates the pathogenesis and complicates the clinical management. In the absence of reliable outcome data in the context of dialysis prescription, requirement of renal replacement therapy in patients with severe electrolyte disturbances constitutes a therapeutic challenge. Recommendations for intradialytic management are based on pathophysiologic reasoning and clinical observations only, and as such, heterogeneous and limited to expert opinion level. This article reviews current strategies for the management of severe hyperkalemia and hyponatremia in hemodialysis patients.

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

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.

Treatment of Severe Hyperkalemia: Confronting 4 Fallacies

Severe hyperkalemia is a medical emergency that can cause lethal arrhythmias. Successful management requires monitoring of the electrocardiogram and serum potassium concentrations, the prompt institution of therapies that work both synergistically and sequentially, and timely repeat dosing as necessary. It is of concern then that, based on questions about effectiveness and safety, many physicians no longer use 3 key modalities in the treatment of severe hyperkalemia: sodium bicarbonate, sodium polystyrene sulfonate (Kayexalate [Concordia Pharmaceuticals Inc., Oakville, ON, Canada], SPS [CMP Pharma, Farmville, NC]), and hemodialysis with low potassium dialysate. After reviewing older reports and newer information, I believe that these exclusions are ill advised. In this article, I briefly discuss the treatment of severe hyperkalemia and detail why these modalities are safe and effective and merit inclusion in the treatment of severe hyperkalemia.

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

BACKGROUND

Sudden death is a leading cause of death in patients on maintenance hemodialysis therapy. During hemodialysis sessions, the gradient between serum and dialysate levels results in rapid electrolyte shifts, which may contribute to arrhythmias and sudden death. Controversies exist about the optimal electrolyte concentration in the dialysate; specifically, it is unclear whether patient outcomes differ among those treated with a dialysate potassium concentration of 3 mEq/L compared to 2 mEq/L.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

55,183 patients from 20 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 1 to 5 (1996-2015).

PREDICTOR

Dialysate potassium concentration at study entry.

OUTCOMES

Cox regression was used to estimate the association between dialysate potassium concentration and both all-cause mortality and an arrhythmia composite outcome (arrhythmia-related hospitalization or sudden death), adjusting for potential confounders.

RESULTS

During a median follow-up of 16.5 months, 24% of patients died and 7% had an arrhythmia composite outcome. No meaningful difference in clinical outcomes was observed for patients treated with a dialysate potassium concentration of 3 versus 2 mEq/L (adjusted HRs were 0.96 [95% CI, 0.91-1.01] for mortality and 0.98 [95% CI, 0.88-1.08] for arrhythmia composite). Results were similar across predialysis serum potassium levels. As in prior studies, higher serum potassium level was associated with adverse outcomes. However, dialysate potassium concentration had only minimal impact on serum potassium level measured predialysis (+0.09 [95% CI, 0.05-0.14] mEq/L serum potassium per 1 mEq/L greater dialysate potassium concentration).

LIMITATIONS

Data were not available for delivered (vs prescribed) dialysate potassium concentration and postdialysis serum potassium level; possible unmeasured confounding.

CONCLUSIONS

In combination, these results suggest that approaches other than altering dialysate potassium concentration (eg, education on dietary potassium sources and prescription of potassium-binding medications) may merit further attention to reduce risks associated with high serum potassium levels.

Low Potassium Dialysate as a Protective Factor of Sudden Cardiac Death in Hemodialysis Patients with Hyperkalemia

AIM

Hyperkalemia increases the risk of sudden cardiac death (SCD) in hemodialysis patients. Our objective was to determine the association between administering low potassium dialysate to hyperkalemic hemodialysis patients and SCD.

METHODS

We conducted a retrospective cohort study with patients undergoing maintenance hemodialysis from May 1, 2006, through December 31, 2013. The dialysate composition was adjusted over time according to monthly laboratory results. A 1.0 mEq/L potassium dialysate was applied in patients with predialysis hyperkalemia (>5.5 mEq/L) and was included as a time-dependent confounding factor. The clinical characteristics of enrolled patients, the incidence and timing of SCD and risk factors for all-cause mortality and SCD were analyzed.

RESULTS

There were 312 patients on maintenance hemodialysis during the study period. One hundred and fifty-seven patients had been dialyzed against a 1.0 mEq/L potassium dialysate at least once. The rates of all-cause mortality and SCD were 48.17 and 20.74 per 1000 patient-years, respectively. A 1.12-fold increase in the risk of SCD in the 24-hour period starting with the hemodialysis procedure and a 1.36-fold increase in the 24 hours preceding a weekly cycle were found (p = 0.017). Multivariate Cox proportional hazards models showed that age, diabetes mellitus and predialysis hyperkalemia (>5.0 mEq/L) were significant predictors of all-cause mortality and SCD. Exposure to 1.0 mEq/L potassium dialysate, Kt/V, and serum albumin were independent protective factors against all-cause mortality. Only exposure to 1.0 mEq/L potassium dialysate significantly prevented SCD (hazard ratio = 0.33, 95% CI = 0.13-0.85).

CONCLUSIONS

Using low potassium dialysate in hyperkalemic hemodialysis patients may prevent SCD.

Low dialysate potassium concentration: an overrated risk factor for cardiac arrhythmia?

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.