Intravenous solution of 0.45% sodium chloride is a/an solution.

AIIMS Patna NO - 2020

Nursing Foundation

Easy

Appeared in: AIIMS Patna NO - 2020

Explanation

45% NaCl is commonly known as half-normal saline and is classified as a hypotonic solution.
It has a lower solute concentration (osmolality of approximately 154 mOsm/L) compared to the body's plasma (which is around 280-300 mOsm/L).
Due to this lower concentration, administering this fluid causes a net movement of water from the extracellular space (bloodstream) into the intracellular space (body cells), leading to cellular hydration and swelling.

Option A: This is incorrect. 0.45% NaCl is a crystalloid solution, which contains small molecules (electrolytes) that can pass through semipermeable membranes. Colloid solutions contain large molecules like proteins (e.g., albumin) or starches that remain in the intravascular space to expand plasma volume.
Option B: This is incorrect. Hypertonic solutions have a higher solute concentration than body fluids, which causes water to be pulled out of the cells, making them shrink. 0.45% NaCl has a lower concentration and does the opposite.
Option D: This is incorrect. Isotonic solutions have a solute concentration similar to that of body fluids, resulting in no significant fluid shift between the intravascular and intracellular compartments. 0.45% NaCl has half the tonicity of an isotonic solution.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of intravenous fluids based on tonicity as background academic context rather than a clinical decision trigger.
Hypotonic solutions like 0.45% NaCl are clinically used to treat conditions involving cellular dehydration, such as hypernatremia or diabetic ketoacidosis (DKA), after initial fluid resuscitation with an isotonic solution.
It is crucial for nurses to monitor for signs of fluid shifts, such as changes in level of consciousness, which could indicate cerebral edema, or worsening hypotension as fluid moves out of the vascular space.
What if? If a patient had increased intracranial pressure (ICP) or was at high risk for cerebral edema (e.g., after a stroke or head injury), administering a hypotonic solution like 0.45% NaCl would be contraindicated. It would worsen the swelling by shifting fluid into the brain cells. In such cases, an isotonic or even a hypertonic solution (like 3% NaCl) would be indicated.

How to Approach the Question

First, identify the core of the question: it asks you to classify the intravenous solution '0.45% sodium chloride'.
Recall the baseline for IV solutions: 0.9% sodium chloride is known as 'Normal Saline' and is the standard isotonic solution.
Compare the given concentration (0.45%) to the isotonic standard (0.9%). Notice that 0.45% is exactly half the concentration of normal saline.
Apply the definitions of tonicity: 'Hypo-' means 'less than' or 'under'. Since the solution has fewer solutes than normal body fluid, it is hypotonic.
Conversely, 'Hyper-' means 'more than' or 'over'. A solution like 3% NaCl would be hypertonic.
Based on this reasoning, select the 'Hypotonic' option.

Concept Tested & Keywords

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