Anesthesia Technician Practice Exam

Which solution is known as a plasma volume expander?

1. Crystalloid

2. Saline solution

3. Colloid

4. Dextrose

The correct answer is: Colloid

A plasma volume expander is designed to increase the volume of plasma in the blood due to its ability to draw fluids into the vascular space. Colloids are characterized by their large molecular size, which allows them to retain fluid within the circulatory system, thus effectively expanding plasma volume. Common examples of colloids include solutions like dextran and hydroxyethyl starch. In contrast, crystalloid solutions, such as saline or dextrose solutions, primarily work by distributing evenly across the extracellular and intracellular spaces, which may not provide the same volume-expanding effect as colloids. They are useful for hydration and electrolyte balance rather than direct plasma volume expansion. Therefore, the distinction lies in the molecular properties and the mechanisms by which each type of solution acts within the body, making colloids the appropriate choice for plasma volume expansion.