A patient suffering from shock is receiving normal saline (NS). What is the normal osmolarity of Na\ in NS? - NORCET 2 -2021 (Shift-2)

NORCET 2 -2021 (Shift-2)

Pharmacology

Easy

Appeared in: NORCET 2 -2021 (Shift-2)

Explanation

Normal Saline (NS) is a solution of 0.9% sodium chloride (NaCl).
By definition, it contains 154 milliequivalents per liter (mEq/L) of sodium (Na⁺) and 154 mEq/L of chloride (Cl⁻).
This concentration makes it an isotonic solution, meaning it has a similar solute concentration to blood plasma.
It is used for fluid resuscitation in conditions like shock to expand the intravascular volume.
The image of the IV bag label explicitly states that it contains 154 mEq/L of sodium.

Option B: A sodium concentration of 100 mEq/L is incorrect for Normal Saline. This value does not correspond to any standard resuscitation fluid.
Option C: A sodium concentration of 130 mEq/L is incorrect for Normal Saline. This is a common distractor because it is the sodium concentration found in another isotonic fluid.
Option D: A sodium concentration of 126 mEq/L is incorrect for Normal Saline and does not match any standard IV fluid composition.

Visual 1: Image - A labeled IV bag of 0.9% Sodium Chloride, clearly showing the electrolyte concentrations (154 mEq/L for both Na⁺ and Cl⁻). This provides direct evidence for the correct answer.
Visual 2: Table - A comparison chart of common intravenous fluids (Normal Saline, Lactated Ringer's, 0.45% NaCl, D5W), detailing their electrolyte composition, osmolarity, and primary uses. This helps differentiate between the fluids.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Composition and Osmolarity of Normal Saline (0.9% NaCl) in acute care settings.
Understanding the composition of IV fluids is critical for safe nursing practice, especially during fluid resuscitation in emergencies like shock.
Administering the correct fluid type is essential to restore hemodynamic stability without causing electrolyte imbalances.
While Normal Saline is a mainstay for resuscitation, administering large volumes can lead to hyperchloremic metabolic acidosis due to its high chloride content (154 mEq/L) compared to plasma (about 103 mEq/L).

How to Approach the Question

First, identify the core of the question. It asks for the sodium (Na⁺) concentration in Normal Saline (NS).
This is a factual recall question based on pharmacology and fluid/electrolyte management.
Recall the definition of Normal Saline. It is a 0.9% solution of sodium chloride.
Access your memory of the standard compositions of common IV fluids. Normal Saline contains 154 mEq/L of Na⁺ and 154 mEq/L of Cl⁻.
If an image is provided, as in this case, examine it closely. The label on the IV bag directly states the concentration of sodium is 154 mEq/L, confirming the answer.
Evaluate the options. 130 mEq/L is the concentration for Lactated Ringer's, a common distractor. The other options are incorrect values.

Concept Tested & Keywords

Concept Tested: Composition and Osmolarity of Normal Saline (0.9% NaCl)
Stem keywords: shock, normal saline (NS), osmolarity, Na+
Lead-in keywords: What is
Clinical cues: Patient in shock receiving normal saline is a key clinical scenario indicating fluid resuscitation.

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