Which solution causes the shifting of fluid from the cell to intravascular compartment?

NORCET -4 , 2023

Applied Physiology

Medium

Appeared in: NORCET -4 , 2023

Explanation

A hypertonic solution has a higher concentration of solutes (osmolality) than the fluid inside the cells.
This creates an osmotic pressure gradient, causing water to move via osmosis from an area of lower solute concentration (inside the cell) to an area of higher solute concentration (the intravascular space).
This net movement of water out of the cells results in the cells shrinking and an expansion of the intravascular fluid volume.

Option A: An isotonic solution has the same tonicity as intracellular fluid, so there is no net movement of water across the cell membrane. It primarily expands the extracellular fluid volume.
Option C: A hypotonic solution has a lower solute concentration than the cell. It causes fluid to shift from the intravascular compartment into the cells, causing them to swell.
Option D: Diffusion is the process of solute movement down a concentration gradient. The question asks about a type of solution and the movement of fluid (water), which is primarily governed by osmosis, not diffusion.

Visual 1: Diagram: Show three red blood cells. One in an isotonic solution (normal), one in a hypertonic solution (shrunken), and one in a hypotonic solution (swollen). This visually demonstrates the effect of each solution on cell volume.
Visual 2: Flowchart: Illustrate the process of osmosis when a hypertonic solution is administered, showing water moving from the intracellular fluid (ICF) compartment to the extracellular fluid (ECF) compartment, leading to cell shrinkage.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Fluid Shifts and IV Solution Tonicity as background academic context rather than a clinical decision trigger.
Hypertonic solutions (e.g., 3% Saline) are used cautiously in clinical settings to treat conditions like severe hyponatremia or cerebral edema. By drawing fluid out of swollen brain cells, they can reduce intracranial pressure.
Nurses must administer hypertonic solutions via a central line in a controlled manner, often in an ICU setting, and monitor the patient's neurological status, serum sodium levels, and for signs of fluid volume overload (e.g., pulmonary edema).
What if? If a patient with cerebral edema were mistakenly given a hypotonic solution, it would worsen the condition. The hypotonic fluid would shift into the already swollen brain cells, increasing intracranial pressure and potentially leading to brain herniation and death. This highlights the critical importance of selecting the correct IV fluid.

How to Approach the Question

First, understand the question's core concept: the movement of fluid from inside the cell to the intravascular space (part of the extracellular space).
Recall the principle of osmosis: water moves from an area of lower solute concentration to an area of higher solute concentration across a semipermeable membrane.
For water to leave the cell, the solution outside the cell must have a higher solute concentration.
Define the options based on their tonicity relative to the cell: Isotonic (same concentration), Hypertonic (higher concentration), Hypotonic (lower concentration).
Connect the definition to the required fluid shift. A hypertonic solution has a higher concentration, which will pull water out of the cell.
Evaluate the final option, 'Diffusion,' and recognize it as a process for solute movement, not a type of solution for fluid shifts, making it incorrect in this context.

Concept Tested & Keywords

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