A Doctor ordered to administer a hypotonic intravenous solution to a client. Looking at the following labelled solution, the nurse should choose?

Appeared in: AIIMS Bhopal NO - 2018 (Shift-1st)

Explanation

The physician ordered a hypotonic solution, which has a lower solute concentration than blood plasma.
45% NS (Normal Saline), also known as half-normal saline, is a classic example of a hypotonic crystalloid solution.
Administering a hypotonic solution causes fluid to shift from the extracellular space (blood vessels) into the intracellular space (cells), rehydrating the cells.
This action makes it the appropriate choice for conditions like hypernatremic dehydration, where cells have lost water.

Option B: D5W (5% Dextrose in Water) is isotonic in the bag but becomes physiologically hypotonic once infused because the dextrose is rapidly metabolized. While it provides free water, 0.45% NS is a more direct and standard hypotonic solution without the added variable of dextrose metabolism.
Option C: 90% NS (Normal Saline) is an isotonic solution. Its solute concentration is similar to that of blood plasma, so it does not cause a significant fluid shift between the extracellular and intracellular compartments.
Option D: DNS (Dextrose Normal Saline, typically D5NS) is a hypertonic solution. It has a higher solute concentration than blood, which would pull water out of the cells, worsening cellular dehydration.

Clinical Relevance

Nursing practice connection: Use the key finding related to Classification of intravenous (IV) fluids 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 solution can lead to serious complications.
Administering a hypotonic solution too rapidly can cause a sudden fluid shift into brain cells, leading to cerebral edema, which is a life-threatening emergency. Nurses must monitor for changes in level of consciousness.
What if the patient had low blood pressure and signs of hypovolemia? In that case, an isotonic solution like 0.9% NS would be the priority to expand vascular volume first, before addressing any cellular dehydration.

How to Approach the Question

First, identify the key term in the question: 'hypotonic intravenous solution'.
Recall the definitions of the three types of IV solutions: hypotonic (lower concentration than blood), isotonic (same concentration), and hypertonic (higher concentration).
Systematically classify each of the four options based on these definitions.
Option A, 0.45% NS, is half the concentration of isotonic saline (0.9%), making it hypotonic.
Option B, D5W, is a special case (isotonic in bag, hypotonic in body).
Option C, 0.90% NS, is the definition of an isotonic solution.

Concept Tested & Keywords

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

E6 Pharmacology Nursing Lilley 11e Part 2 p. 168-170

Practise the full AIIMS Bhopal NO - 2018 (Shift-1st)

Attempt every question from this paper in a timed mock, then review the full solution for each one.