**Core Concept**
Dextran is a type of plasma expander used to increase blood volume and improve circulation in patients with hypovolemia or shock. It works by increasing the oncotic pressure in the blood vessels, which in turn increases blood flow and pressure.

**Why the Correct Answer is Right**
Dextran is a polysaccharide molecule that is metabolized by the liver, but it can cause a severe anaphylactoid reaction in some patients. This is because dextran can activate the complement system, leading to the release of histamine and other mediators that cause vasodilation, increased vascular permeability, and bronchospasm.

**Why Each Wrong Option is Incorrect**
* **Option A:** While dextran can cause anaphylactoid reactions, it is not the most significant disadvantage of its use.
* **Option B:** Dextran is actually a good plasma expander, so this option is incorrect.
* **Option C:** While dextran can be metabolized by the liver, this is not a significant disadvantage of its use.

**Clinical Pearl / High-Yield Fact**
Dextran is a type of plasma expander that is often used in emergency medicine, but it can cause severe anaphylactoid reactions in some patients. To minimize this risk, it is essential to carefully screen patients for a history of allergies before administering dextran.

**Correct Answer:** C.