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Hyperkalaemia – cardiac stabilisation — RACP Paediatrics MCQ

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HardEmergencyHyperkalaemia – cardiac stabilisationRACP Paediatrics

A 5-year-old with CKD has potassium 7.8 mmol/L, absent P waves and a broad QRS complex but still has a pulse. Which immediate prescription best protects against cardiac arrest while potassium-lowering therapies are prepared?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Give 10% calcium gluconate 0.68 mL/kg IV over 2–5 minutes with ECG monitoring

Explanation lettering: E = shown as B · B = shown as E

D is correct. With life-threatening ECG changes, RCH recommends 10% calcium gluconate 0.15 mmol/kg, equivalent to 0.68 mL/kg, over two to five minutes with continuous ECG monitoring. It stabilises myocardium but does not lower potassium. E is a tenfold underdose, too slow and unmonitored. A delays immediate membrane stabilisation; insulin and glucose should follow in parallel to shift potassium. B can shift potassium but does not provide calcium’s immediate membrane effect. C has a delayed and unreliable onset and cannot protect the myocardium now. Calcium may be repeated if ECG changes persist while definitive potassium removal and the cause are addressed.

Reference: Royal Children’s Hospital Melbourne: Hyperkalaemia: https://www.rch.org.au/clinicalguide/guideline_index/Hyperkalaemia/