Management of Hyponatremia and Hypokalemia in Hemodialysis Patients
Hyponatremia Management
For hemodialysis patients with hyponatremia, use dialysate sodium concentration of 135-138 mEq/L and control the rate of sodium correction to 4-6 mEq/L per 24 hours (maximum 8-10 mEq/L in first 24 hours) to prevent osmotic demyelination syndrome while achieving volume and blood pressure control. 1, 2
Acute Correction Strategy for Severe Hyponatremia
Reduce blood flow rate to 50 mL/minute during initial hemodialysis sessions to slow sodium correction when serum sodium is severely low (e.g., <115 mEq/L). 3
Use dialysate sodium of 130-135 mEq/L for patients with severe hyponatremia, as this prevents excessively rapid correction that occurs with standard dialysate (140 mEq/L or higher). 2, 3
Monitor serum sodium every 2-4 hours during initial dialysis sessions to ensure correction rates remain within the safe 4-6 mEq/L per 24-hour target. 1
Minimize ultrafiltration volume during initial sessions, as aggressive fluid removal combined with sodium diffusion accelerates correction beyond safe limits. 2
For patients requiring both volume removal and controlled sodium correction, continuous venovenous hemofiltration with customized low-sodium replacement fluid allows precise control of correction rate through single-pool sodium kinetic modeling. 4, 5
Long-Term Maintenance Strategy
Maintain dialysate sodium at 135-138 mEq/L for ongoing treatments, as this range optimizes outcomes without promoting thirst or interdialytic weight gain. 1
Avoid dialysate sodium ≥140 mEq/L, which increases thirst, interdialytic weight gain, hypertension, and cardiovascular workload—all contributing to increased morbidity and mortality. 6, 1, 7, 2
Discourage sodium profiling (starting at 145-155 mEq/L and decreasing), as this technique produces the same adverse effects as sustained high dialysate sodium. 6, 2
Dietary and Fluid Management
Implement dietary sodium restriction to 2-3 g/day (85-100 mmol/day) to minimize interdialytic sodium accumulation and facilitate achievement of dry weight. 1, 2
Review fluid intake patterns, as excessive free water consumption between dialysis sessions is a common cause of hyponatremia in dialysis patients. 2
Limit fluid intake to 1-1.5 L/day if the patient is hypervolemic with persistent hyponatremia. 2
Critical Safety Monitoring
Continuously assess neurological status for signs of osmotic demyelination syndrome, including confusion, altered consciousness, seizures, or new neurological deficits. 1, 2
The lag phenomenon means that blood pressure normalization may take time despite proper volume control—do not interpret persistent hypertension as treatment failure during the initial correction phase. 6
Hypokalemia Management
For hemodialysis patients with hypokalemia, increase dialysate potassium concentration and provide oral potassium supplementation with controlled-release preparations, as hypokalemia in HD patients poses significant risks for cardiac arrhythmias and digitalis toxicity. 8, 9
Dialysate Potassium Adjustment
Increase dialysate potassium concentration to 3.0-4.0 mEq/L to prevent excessive potassium removal during dialysis sessions. 9
Standard hemodialysis removes 70-150 mmol of potassium per session through diffusion, and this removal is increased by glucose-free dialysate and sodium profiling. 9
Oral Potassium Supplementation
Use controlled-release potassium chloride preparations for patients who cannot tolerate or refuse liquid/effervescent preparations, though these should be reserved due to risks of intestinal and gastric ulceration. 8
Potassium supplementation is particularly critical for digitalized patients, those with significant cardiac arrhythmias, or patients with potassium-losing conditions. 8
Monitoring and Prevention
Check serum potassium periodically between dialysis sessions to guide supplementation needs. 8
Review medications that may contribute to hypokalemia, including any residual diuretic use. 8
Unlike peritoneal dialysis patients (who frequently develop hypokalemia due to glucose-mediated intracellular potassium shift), hemodialysis patients more commonly experience hyperkalemia, making true hypokalemia an important finding requiring investigation. 9
Common Pitfalls to Avoid
Do not use high dialysate sodium (≥140 mEq/L) thinking it will help with hypotension, as this creates a vicious cycle of thirst, weight gain, and worsening hypertension. 6, 7
Do not aggressively correct hyponatremia in the first dialysis session—the risk of osmotic demyelination syndrome outweighs the urgency of correction unless the patient is severely symptomatic. 1, 2
Do not overlook residual kidney function preservation, as this is one of the most important predictors of patient survival and allows better fluid and electrolyte balance. 6