A nurse is preparing to administer IV fluids that raise serum osmolarity to pull fluid into the vascular compartment. Which fluid should the nurse administer?

Hypertonic

Explanation

•The correct answer is hypertonic solution.

Hypertonic solution contains more solutes than the serum, making its osmolarity higher. This will raise the serum osmolarity of the blood and pull fluid from the intracellular compartment into the vascular space by diffusion (due to the concentration gradient), raising the blood volume.

•The fluid moves to where the solutes are more concentrated to try to balance it out. After the fluid is given, even more fluid will be drawn into the vascular compartment due to the high osmolarity there.

Hypotonic solution contains fewer solutes than the serum, making its osmolarity lower. This will lower the serum osmolarity of the blood and the excess fluid in the blood will move out of the vascular space into the intracellular compartment by diffusion (due to the concentration gradient).

Isotonic solution has equal osmolarity compared to normal serum. This does not create a concentration gradient and does not pull fluids into or out of the vascular space, so it allows rehydration that expands blood volume but also allows fluid to move into the intracellular compartment as needed.

•Supratonic solution does not exist.

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