Potassium in pre-dialysis patients

Guidelines
No recommendations possible based on Level I or II evidence

Suggestions for Clinical Care
(Suggestions are based on Level III and IV evidence)

Serum potassium should be regularly monitored, and a reduced potassium diet commenced when serum potassium is greater than 5.5 mmol/L. (Opinion)

The risk of cardiac arrhythmias is higher when the potassium is above 6.5 mmol/L or when the potassium is below 3.0 mmol/L. Patients who are especially at risk of cardiac arrhythmias are those with ischaemic heart disease, previous arrhythmias, or low serum calcium.

Potassium excretion is maintained in renal disease unless distal tubular urine flows or aldosterone secretion is affected.

When hyperkalaemia develops in the chronic kidney disease (CKD) patient, one of the following should be looked for, and when possible, corrected:
- High potassium intake (including salt substitutes in sodium-reduced diets)
- Oliguria
- Hypoaldosteronism
- Metabolic acidosis
- Medications that either contain potassium or inhibit the clearance of potassium, such as angiotensin-converting enzyme (ACE) inhibitors, corticosteroids, and potassium-sparing diuretics

Conversely, hypokalaemia may develop in the CKD patient when:
- A low potassium diet is implemented, including poor/low food nutrition intake
- Overuse or inappropriate use of potassium-lowering agents is occurring, e.g. ion-exchange resins
- Overuse or inappropriate use of diuretics is present

A reduced potassium diet should limit the 24-hour intake to approximately 80 mmol.