Hypotonic crystalloids cause cell volume to do what?

• A. Increases
• B. Decreases
• C. No change
• D. Varies

Answer: (A)

Hypotonic crystalloids have lower solute concentration outside the cells than inside. Water moves by osmosis from the extracellular space into the cells to balance solute differences, so cells take in water and swell. The net effect is an increase in cell volume. This is distinct from hypertonic solutions, which shrink cells, and isotonic solutions, which largely don’t change cell volume; hypotonic fluids can lead to cellular edema if given in excess, so they’re used with caution.