Treating hyperkalaemia

Overview

Emergency treatment for life-threatening hyperkalaemia of any cause (except acute digoxin toxicity or chronic digoxin accumulation) is to:

give intravenous calcium gluconate (which has an immediate cardiac stabilising effect)
correct any volume depletion.

In kidney failure, intravenous glucose and insulin are effective.

If metabolic acidosis is present, intravenous bicarbonate is effective but may not lower potassium immediately.

Emergency treatment for primary adrenal insufficiency should include intravenous hydrocortisone but not insulin.

Less urgent treatment (generally for patients in kidney failure) is to use a sodium or calcium exchange resin.

Intravenous calcium gluconate

Calcium alleviates the membrane depolarisation of severe hyperkalaemia, without lowering the serum potassium concentration. In the presence of life-threatening cardiac arrhythmia or severe ECG changes of acute hyperkalaemia, use:

calcium gluconate 0.22 mmol/mL¹ 2.2 mmol (10 mL) IV over 2 to 3 minutes into a large vein. Monitor response by ECG if possible. hyperkalaemia

The effect of this infusion is short-lived. The dose may need to be repeated in 30 to 60 minutes, while undertaking specific measures to reduce potassium.

Correcting volume depletion

Any volume depletion should be corrected so that kidney function is optimised.

Intravenous sodium bicarbonate

If metabolic acidosis is associated with volume depletion, the first choice for treating severe confirmed hyperkalaemia is:

sodium bicarbonate 8.4% (= 1 mmol/mL) 50 mL IV over 5 to 10 minutes, under ECG control. This may be repeated in 60 to 120 minutes. hyperkalaemia

Fluid replacement may need to be continued with sodium chloride 0.9%.

Insulin

Insulin promotes cellular uptake of potassium. Serum potassium decreases by 0.5 to 1.5 mmol/L over 30 minutes in response to the insulin–glucose therapy below. Insulin and glucose is the treatment of choice for severe hyperkalaemia associated with chronic kidney failure, when a sodium load is contraindicated.

Hypoglycaemia must be ruled out before giving insulin. Profound refractory hypoglycaemia can be induced by giving insulin in the presence of adrenal insufficiency.

In all patients, measure blood glucose concentration before starting insulin–glucose therapy, then every 30 minutes for 2 hours, then hourly for the next 4 hours (ie for a total of 6 hours after the insulin–glucose therapy).

Glucose 50% may cause vascular irritation when administered peripherally—glucose 10% is an alternative, if available. Use:

short-acting insulin 10 units IV bolus (see Action profiles of insulin formulations for insulin formulations) hyperkalaemia

PLUS EITHER

glucose 50% 50 mL IV over 5 minutes hyperkalaemia: initial therapy

OR

glucose 10% 250 mL IV over 15 minutes.

Some patients develop hypoglycaemia (sometimes severe) after insulin–glucose therapy. If hypoglycaemia develops after insulin–glucose therapy, treat with glucose as for severe hypoglycaemia in adults with diabetes.

Certain patients are at higher risk of:

hypoglycaemia (see Common precipitants and patient risk factors for hypoglycaemia)
an adverse event if hypoglycaemia were to occur (eg those starting anaesthesia or being transferred by ambulance).

In these patients, an alternative approach is to start a glucose infusion after the initial insulin–glucose therapy, while measuring blood glucose concentration as above. Use:

glucose 10% IV infusion at 75 to 100 mL/hour. hyperkalaemia: following initial therapy

Removing potassium from the bowel lumen

Potassium can be removed from the bowel lumen, in exchange for sodium or calcium, by using a polystyrene sulfonate resin. This treatment takes several hours for effect.

With a sodium exchange resin, use:

1 sodium polystyrene sulfonate 15 g (suspended in 45 to 60 mL of water) orally, 3 or 4 times daily hyperkalaemia sodium polystyrene sulfonate

OR

1 sodium polystyrene sulfonate 30 to 50 g (suspended in 150 mL of water or 10% glucose) rectally as a retention enema, daily. sodium polystyrene sulfonate

Each gram of resin removes about 1 mmol of potassium and delivers 2 to 3 mmol of sodium. This treatment lowers the serum potassium concentration by 0.5 to 1 mmol/L over 1 to 6 hours. Sodium loading can be a disadvantage.

If adding to the sodium load is a problem, a calcium exchange resin can be used instead. Use:

1 calcium polystyrene sulfonate 15 g (suspended in 45 to 60 mL of water) orally, 3 or 4 times daily hyperkalaemia

OR

1 calcium polystyrene sulfonate 30 to 50 g (suspended in 150 mL of water or 10% glucose) rectally as a retention enema, daily.

A calcium exchange resin should not be used if the patient has a condition associated with hypercalcaemia.

To avoid overtreatment and hypokalaemia, treatment with an ion exchange resin should stop when the serum potassium is lower than 5 mmol/L.

Dialysis

When hyperkalaemia is extreme (eg in extensive tissue breakdown due to rhabdomyolysis), none of the above approaches may be effective. If so, dialysis is necessary.

Adrenal insufficiency and hypoaldosteronism

When hyperkalaemia is due to adrenal insufficiency, corticosteroid replacement is the main treatment. Insulin should be avoided.

Medication review

Drugs that may cause or aggravate hyperkalaemia (see Common causes of hyperkalaemia) should be stopped. Drug-related hyperkalaemia is especially common when kidney function is impaired.