There are three main routes of elimination available to us. We can use diuretics to increase urinary potassium excretion. Exchange resins can bind and excrete potassium in the GI tract. We can also filter the blood to remove potassium.
Furosemide
Dose: 40-80mg IV as a bolus
Can be very useful in patients with fluid overload
Calcium Resonium
Dose: 15g TDS orally, or 30g rectally retained for 9 hours followed by irrigation
Complications: constipation, gastrointestinal necrosis
There is little to no evidence that calcium resonium effectively reduces serum potassium levels, and multiple case reports of severe gastrointestinal complications. Consideration of this should be undertaken before prescription.
Haemodialysis/filtration
This is the definitive treatment for hyperkalaemia, particularly if this is refractory to medical management, the patient is acidotic, oligo/anuric, or already on dialysis. Such patients should be discussed early with the intensivists and nephrologists.
As well as trying to eliminate excess potassium, we also need to make sure we don’t contribute too much to the potassium load. It’s important to check the drug chart, and consider stopping potassium-sparing/containing drugs, and to put the patient on a low potassium diet.