If a doctor has prescribed Hypotonic IV solution for a patient, which of the following solutions will the Nurse/CHO use?

Appeared in: Uttarakhand CHO - 2021

Explanation

Hypotonic solutions have a lower solute concentration than body fluids, causing water to move into cells.
45% Saline (Half-Normal Saline) has an osmolarity of approximately 154 mOsm/L, which is significantly lower than the blood's osmolarity (around 275-295 mOsm/L), making it a hypotonic solution.
It is specifically used to treat cellular dehydration by shifting fluid from the extracellular space into the cells.

Option B: 5% Dextrose in Saline (assuming 0.9% Saline, D5NS) is a hypertonic solution. Its high osmolarity (approx. 560 mOsm/L) would draw water out of cells, which is the opposite effect of a hypotonic solution.
Option C: 10% Dextrose in Water (D10W) is a hypertonic solution in the bag due to its high dextrose concentration (approx. 505 mOsm/L). Although the dextrose is metabolized, leaving free water (a hypotonic effect), the initial solution is hypertonic.
Option D: 5% Dextrose in 0.9% Saline (D5NS) is a hypertonic solution with an osmolarity of about 560 mOsm/L. It increases the osmolarity of the blood, causing fluid to shift from the intracellular to the extracellular space.

Clinical Relevance

Nursing practice connection: Use the key finding related to Classification and clinical use of intravenous (IV) solutions based on tonicity to guide bedside assessment, documentation, and the next nursing action.
Administering the correct IV fluid is a critical nursing responsibility. Using the wrong type can lead to serious complications like cerebral edema (with hypotonic fluids) or cellular dehydration (with hypertonic fluids).
Nurses must always double-check the provider's order against the IV bag and understand the rationale for the prescribed fluid.
What if the patient had increased intracranial pressure (ICP)? In that case, administering a hypotonic solution like 0.45% Saline would be contraindicated. It would cause fluid to shift into the brain cells, worsening the swelling and increasing the ICP, which could be fatal. A hypertonic solution (like 3% Saline) might be used instead to draw fluid out of the brain cells.

How to Approach the Question

First, identify the key term in the question: 'Hypotonic IV solution'.
Define 'hypotonic': a solution with a lower solute concentration than the body's cells.
Recall or look up the properties of the common IV fluids listed in the options.
Evaluate each option: A) 0.45% Saline is half the concentration of normal saline (0.9%), making it hypotonic. B) D5NS is a combination of dextrose and normal saline, making it hypertonic. C) D10W has a high concentration of dextrose, making it hypertonic. D) D5 in 0.9% Saline is the same as option B and is hypertonic.
Conclude that 0.45% Saline is the only hypotonic solution among the choices.

Concept Tested & Keywords

Concept Tested: Classification and clinical use of intravenous (IV) solutions based on tonicity.
Stem keywords: Hypotonic IV solution, prescribed
Lead-in keywords: which of the following

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E6 Nursing Brunner Adult Health 3SA Vol 1 Part 1 p. 142-144

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 68-70

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