IV Fluids — Saline vs Dextrose

Current · V5 (2025) → F2.i Historical · V4 (2023) → I2.i 1 exam appearance

2018A Q17

Exam question

Define the osmolality and tonicity of an intravenous fluid (20% of marks). Compare and contrast the pharmacology of intravenous Normal Saline 0.9% and 5% Dextrose (80% of marks).

CICMWrecks answer

Master answer

Definitions

Osmolality is a measure of solute concentration as defined as the number of osmotically active particles per kilogram water.

Tonicity is the effective osmolality and is equal to the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane.

Pharmacology

CICMWrecks Table – NS | 5% Dex (Click to Open)

Past papers

Exam appearances

1 appearance

Exam	Exact exam wording	Candidate success
2018A Q17	Define the osmolality and tonicity of an intravenous fluid (20% of marks). Compare and contrast the pharmacology of intravenous Normal Saline 0.9% and 5% Dextrose (80% of marks).	29%