Which of the following component is not present in normal saline?

Appeared in: AIIMS Delhi NO- 2019

Explanation

Normal Saline is an isotonic solution containing 0.9% sodium chloride.
Its primary components are Sodium (Na+) at a concentration of 154 mEq/L and Chloride (Cl-) at 154 mEq/L.
The solution is specifically formulated without potassium (K+), making it a suitable choice when potassium administration is not desired.
Therefore, K+ 52 mEq/L is the component that is not present in normal saline.

Option A: This is incorrect because Sodium (Na+) at a concentration of 154 mEq/L is a primary and defining component of normal saline.
Option B: This is incorrect because Chloride (Cl-) at a concentration of 154 mEq/L is the other primary and defining component of normal saline.
Option D: This option is incorrect because a component listed in the options (K+ 52 mEq/L) is indeed absent from normal saline.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Composition of Normal Saline (0.9% NaCl) as background academic context rather than a clinical decision trigger.
Normal Saline (NS) is one of the most frequently used IV fluids for volume expansion in cases of dehydration, shock, and hemorrhage. It is also the only fluid that can be administered with blood products.
Nurses must be aware that administering large volumes of NS can lead to hyperchloremic metabolic acidosis due to the high chloride content (154 mEq/L) compared to plasma (about 103 mEq/L).
What if the patient had severe kidney injury with hyperkalemia (high potassium)? Normal Saline would be a preferred fluid over Ringer's Lactate, as NS is potassium-free, whereas Ringer's Lactate contains 4 mEq/L of potassium, which could worsen the patient's condition.

How to Approach the Question

First, identify the core of the question, which asks what is not a component of normal saline. The word 'not' is critical.
Recall the definition and composition of 'normal saline'. It is 0.9% sodium chloride (NaCl).
Break down 'sodium chloride' into its ionic components: Sodium (Na+) and Chloride (Cl-).
Evaluate each option against this knowledge:
Option A (Na+ 154 mEq/L): This is the correct concentration of sodium in normal saline.
Option B (Cl- 154 mEq/L): This is the correct concentration of chloride in normal saline.

Concept Tested & Keywords

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