A 68-year-old man is brought in drowsy after a week of polyuria. Glucose is 1050 mg/dL, effective serum osmolality 338 mOsm/kg, pH 7.39, bicarbonate 23 mEq/L, serum ketones trace, and creatinine 2.4 mg/dL. He has no chest pain. What is the priority in the first hour of resuscitation?

• A 0.45% (half-normal) saline intravenously
• B 0.9% (isotonic) saline intravenously ✓
• C 5% dextrose with insulin infusion
• D Sodium bicarbonate infusion

Explanation

This is hyperosmolar hyperglycemic state: profound hyperglycaemia, effective osmolality above 320, minimal ketosis, and preserved pH. The dominant problem is severe free water deficit with volume depletion, so resuscitation begins with isotonic saline to restore intravascular volume and perfusion, followed by insulin. Half-normal saline is considered only after the initial deficit improves or if osmolality remains very high with stability. Dextrose is given later once glucose approaches 250 mg/dL, and there is no acidosis to justify bicarbonate.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.