Quick answerSevere hyperkalemia with ECG changes; give prescribed IV calcium gluconate and IV regular insulin with dextrose, then monitor serum potassium and QRS duration.
Why this is correctA widening QRS shows potassium is already affecting conduction and can progress to ventricular arrhythmia or asystole. Calcium does not lower potassium but raises the threshold for depolarization and protects the heart; insulin drives potassium into cells within about 15 to 30 minutes. Removal therapies follow once the heart is protected.
Easy analogy or mental picturePicture a flooded engine room: first put up a shield (calcium) so sparks cannot ignite, then pump water into side tanks (insulin), and finally drain the ship (binder and dialysis).
Memory hookShield, shift, then shed: calcium, insulin with glucose, then binder or dialysis.
NCLEX decision ruleWhen hyperkalemia changes the ECG, protect the heart and shift potassium before choosing slower removal therapies, and monitor both the level and the ECG.
Why the other choices are wrongA potassium binder is correct but works over hours, so giving it first delays life-saving treatment. Nitroglycerin and a troponin trend target myocardial infarction, which normal troponin and no chest pain make unlikely despite peaked T waves. Hypocalcemia prolongs the QT interval, and calcium here is normal. Magnesium sulfate treats torsades de pointes and does not lower potassium, and the magnesium level is normal. Serum sodium does not track this emergency.
References
1MedlinePlus — High potassium levelSevere hyperkalemia causes dangerous heart rhythm changes and needs emergency treatment.
2DailyMed — Sodium zirconium cyclosilicate labelingThe label states it should not be used as emergency treatment for life-threatening hyperkalemia because of delayed onset.