A 68-year-old man with CKD stage 4 presents with serum potassium 6.9 mmol/L, broad QRS complexes and peaked T waves on ECG. He is haemodynamically stable. According to emergency care protocols, which is the most urgent first step in management?AAdminister intravenous calcium gluconateBAdminister oral sodium polystyrene sulfonateCStart oral sodium bicarbonateDArrange urgent dialysis without any immediate medical therapyEAdvise dietary potassium restriction onlyCheck my answer