In the management of diabetic ketoacidosis, intravenous sodium bicarbonate is indicated only under which specific condition?
- A Serum potassium below 5.2 mEq/L at presentation
- B Arterial pH below 6.9 despite standard fluid and insulin therapy ✓
- C Blood glucose above 600 mg/dL refractory to fluids
- D Any patient with a high anion gap above 16 mEq/L
Correct answer: B. Arterial pH below 6.9 despite standard fluid and insulin therapy
Explanation
Insulin therapy itself resolves the ketoacidosis, and controlled trials show no benefit of bicarbonate in patients with pH above 6.9, while its use risks hypokalaemia, paradoxical cerebral acidosis and delayed ketone clearance. Guidelines reserve bicarbonate for severe acidaemia with pH below 6.9, given as isotonic bicarbonate with added potassium. An elevated anion gap alone never mandates bicarbonate, since the gap simply reflects accumulating ketoacids that insulin will clear.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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