Which fluids are isotonic, according to the material?

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Multiple Choice

Which fluids are isotonic, according to the material?

Isotonic fluids have an osmolality close to that of blood plasma, so they stay in the extracellular space and don’t cause water to move into or out of cells. Normal saline 0.9% and lactated Ringer’s fit this profile because their tonicity is essentially similar to plasma, making them reliable for expanding extracellular fluid without shifting water into cells. Dextrose 5% in water starts with a tonicity similar to plasma, but once the glucose is metabolized, it leaves free water, which then acts as hypotonic—so it isn’t considered consistently isotonic. Dextrose 5% in saline adds solutes, making that solution hypertonic. Hypotonic saline is itself hypotonic and does not count as isotonic.

Isotonic fluids have an osmolality close to that of blood plasma, so they stay in the extracellular space and don’t cause water to move into or out of cells. Normal saline 0.9% and lactated Ringer’s fit this profile because their tonicity is essentially similar to plasma, making them reliable for expanding extracellular fluid without shifting water into cells.

Dextrose 5% in water starts with a tonicity similar to plasma, but once the glucose is metabolized, it leaves free water, which then acts as hypotonic—so it isn’t considered consistently isotonic. Dextrose 5% in saline adds solutes, making that solution hypertonic. Hypotonic saline is itself hypotonic and does not count as isotonic.

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