A patient receives 500 mL of 5% dextrose intravenously. The dextrose is rapidly metabolized to CO2 and water. After metabolism, the free water distributes across body fluid compartments. What is the approximate volume that enters the intracellular fluid compartment?

• A 333 mL ✓
• B 500 mL (entire volume stays in ECF)
• C 167 mL
• D 250 mL

Explanation

5% dextrose is isotonic in the bag but once dextrose is metabolized, it behaves as free water. Free water distributes across total body water (approximately 60% of body weight), with two-thirds entering the intracellular compartment and one-third remaining in the extracellular compartment. For 500 mL of free water, approximately 333 mL enters the ICF and 167 mL stays in the ECF.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.