Ringer's lactate solution is-

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2022

Explanation

Ringer's lactate (RL) is an isotonic crystalloid solution, meaning its solute concentration is similar to that of blood plasma.
The osmolarity of RL is approximately 274 mOsm/L, which falls within the normal range for plasma (275-295 mOsm/L).
Because it is isotonic, it expands the extracellular fluid volume without causing significant shifts of water into or out of cells.
It is a first-line choice for treating fluid volume deficit (hypovolemia), especially in cases of burns, trauma, and acute blood loss.

Option A: A hypotonic solution has a lower osmolarity than plasma, causing fluid to move into cells. Ringer's lactate does not do this; its osmolarity is similar to plasma.
Option B: A hypertonic solution has a higher osmolarity than plasma, drawing water out of cells. Ringer's lactate is isotonic, not hypertonic.
Option D: Colloids are solutions containing large molecules like proteins or starches that act as plasma expanders by increasing oncotic pressure. Ringer's lactate is a crystalloid, containing small electrolyte molecules, not large colloids.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Tonicity of Intravenous Solutions as background academic context rather than a clinical decision trigger.
Ringer's lactate is a go-to fluid for rapid volume replacement in trauma, surgery, and burn patients because its composition closely mimics that of plasma.
Nurses must monitor for signs of fluid overload when administering any IV fluid, but especially with isotonic solutions in patients with heart failure or kidney injury, as they directly expand the ECF.
A key nursing consideration is that Ringer's lactate contains potassium and should be used with caution in patients with renal failure, as they may not be able to excrete potassium, leading to hyperkalemia.

How to Approach the Question

First, identify the core subject of the question, which is 'Ringer's lactate solution'.
The question asks for its classification. The options relate to tonicity (Hypotonic, Hypertonic, Isotonic) and fluid type (Colloid).
Recall the definitions of these terms in the context of IV fluids.
Access your knowledge about common IV solutions. Ringer's lactate is a standard, frequently used fluid.
Remember that Ringer's lactate is designed to be compatible with the body's own fluids, which makes it isotonic.
Differentiate it from colloids, which are protein-based, and from hypotonic/hypertonic solutions, which are used for specific fluid shifts, not general resuscitation.

Concept Tested & Keywords

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

E6 Pharmacology Nursing Lilley 11e Part 2 p. 161-163

E6 Gynecology Williams p. 51-74

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