A 24-year-old man with type 1 diabetes presents in diabetic ketoacidosis: pH 7.02, bicarbonate 4 mEq/L, anion gap 28, glucose 540 mg/dL. He is receiving IV fluids and insulin infusion. In addition to these measures, sodium bicarbonate therapy is indicated in this patient for which specific reason?
- A Anion gap greater than 25 mEq/L
- B Arterial pH less than 6.9 ✓
- C Serum potassium below 3.3 mEq/L
- D Blood glucose above 500 mg/dL
Correct answer: B. Arterial pH less than 6.9
Explanation
ADA guidance reserves bicarbonate for severe acidosis with arterial pH below 6.9, because trials show no benefit at higher pH values and bicarbonate risks hypokalemia, paradoxical CSF acidosis and delayed ketone clearance. An anion gap of 28 does not by itself mandate bicarbonate. Potassium below 3.3 is actually a contraindication to starting insulin until it is corrected, so option C describes a different intervention entirely.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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