The client has severe hyperkalemia (7.2 mEq/L) with ECG changes (peaked T waves, widened QRS), indicating cardiac membrane instability. Intravenous calcium gluconate is the priority because it immediately stabilizes the cardiac membrane and prevents life-threatening arrhythmias. Insulin with dextrose shifts potassium intracellularly but does not provide immediate cardiac protection. Sodium polystyrene sulfonate removes potassium slowly via the GI tract and is not appropriate for acute ECG changes. Hemodialysis is definitive but takes time to arrange; calcium must be given first to protect the heart.
For study reference only. Always follow current clinical guidelines and your institution’s protocols.