A man with heart failure has a serum potassium of 6.4 mmol/L and the ECG shows peaked T waves and a widened QRS. What is the first treatment?
Answer and explanation
Correct answer: C. Intravenous calcium gluconate to stabilise the cardiac membrane
- Step 1: ECG changes show that the myocardium is already threatened. Step 2. Calcium raises the threshold potential within minutes; insulin with glucose and salbutamol then shift potassium into cells. Answer: Intravenous calcium gluconate. Why not the others: Binding resins act over hours. Insulin and glucose lower potassium but do not protect the membrane. Oral diuretics are far too slow in an unstable patient.
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