Acute Carecommon
A 76-year-old man taking ramipril and spironolactone attends with three days of vomiting and increasing lethargy. He is drowsy but rousable. Pulse is 42/min and blood pressure 108/66 mmHg. Serum potassium is 7.4 mmol/L (3.5-5.2) and creatinine 310 micromol/L (60-110). The electrocardiogram shows broad QRS complexes with tall, narrow, peaked T waves and no discernible P waves. Intravenous access is in place and the renal team has been telephoned. Which one of the following should be given first?