Hyperkalaemia Medication Protocol

Hyperkalaemia is mild at 5.5 to 5.9 mmol/L, moderate at 6.0 to 6.4 and severe at 6.5 mmol/L or more, and is an emergency with any ECG change (peaked T waves, flat P waves, wide QRS, sine wave) or arrhythmia. Treatment has three aims: protect the heart, shift potassium into cells, and remove it from the body.

Confirm. Exclude a haemolysed sample, but treat at once when the ECG is abnormal or the patient is unwell.

Causes to stop. ACE inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, NSAIDs, trimethoprim, heparin, potassium supplements and salt substitutes, and suxamethonium.

Protect the heart. Calcium gluconate or calcium chloride.

Shift into cells. Insulin with glucose, nebulised salbutamol, and sodium bicarbonate when acidosis is present.

Remove. Loop diuretic if the patient makes urine, sodium zirconium cyclosilicate, and dialysis.

Special groups.

• Children: use weight-based doses.

• Pregnancy: use the usual adult treatment, with ECG monitoring.

• Kidney failure: the effect of insulin lasts longer, so reduce the dose and monitor glucose for longer.

• East Africa: ask about potassium-containing salt substitutes and herbal products, and use monitored beds for severe cases when dialysis is not immediately available.

• Calcium gluconate 10 percent: 10 mL intravenously over 5 to 10 minutes, repeated after 5 to 10 minutes if ECG changes persist. Calcium chloride 10 percent: 5 to 10 mL through a central line.

• Soluble insulin 10 units intravenously with glucose 25 g (50 mL of 50 percent dextrose) over 15 minutes. Omit the glucose if the blood glucose is over 14 mmol/L. Use 5 units when kidney failure or low body weight makes hypoglycaemia likely.

• Salbutamol: 10 to 20 mg nebulised over 10 minutes, as an addition.

• Sodium bicarbonate: for acidosis, 1.26 percent 500 mL intravenously over 1 hour, or 8.4 percent 50 mL in cardiac arrest.

• Furosemide: 40 to 80 mg intravenously when the patient makes urine.

• Sodium zirconium cyclosilicate: 10 g orally three times daily for up to 48 hours, then 5 to 10 g daily.

• Children: calcium gluconate 10 percent 0.5 mL/kg (maximum 20 mL), insulin 0.1 units/kg with dextrose 0.5 g/kg, salbutamol 2.5 to 5 mg nebulised.

• Digoxin toxicity: digoxin-specific antibody fragments, by specialist direction.

Monitoring. Continuous ECG, potassium at 1 hour, then hourly for 6 hours, and glucose hourly for 6 hours after insulin. Watch for rebound at 2 to 4 hours as insulin and salbutamol wear off.

Stop rules. Stop treatment when potassium is under 5.5 mmol/L and the cause is controlled. Do not give potassium in fluids until it is safe.

Referral and escalation. Contact nephrology for potassium of 6.5 mmol/L or more not responding, acidosis, anuria, or a rising value. Dialysis is indicated for refractory hyperkalaemia.

Common errors. Giving insulin without glucose monitoring, delaying calcium for a normal ECG when the value is very high, forgetting rebound, and continuing the cause.