Plasma substitutes, or plasma expanders, are intravenous fluids given to replace lost blood volume, stabilize blood pressure, and maintain adequate organ perfusion when blood transfusions are unavailable, insufficient, or contraindicated.
Types of Plasma Substitutes
A) Crystalloids
Solutions of electrolytes (e.g., saline, Ringer's lactate).
Advantages: Cheap, safe, rapidly expand extracellular fluid.
Disadvantages: Short-lived intravascular expansion; large volumes required.
B) Colloids
Larger molecular weight substances designed to remain within the vascular compartment longer.
Examples include:
Dextran: Synthetic polysaccharide; expands volume efficiently but risk of allergic reactions, bleeding due to platelet dysfunction.
Hydroxyethyl starch (HES): Synthetic polymer, effective volume expansion but associated with risk of coagulopathy and renal impairment.
Gelatin Solutions: Derived from animal collagen; good volume expansion but can trigger allergic reactions.
Applications of Plasma Substitutes
Emergency Resuscitation: Treats shock and severe blood loss.
Surgery & Trauma: Maintains blood volume when whole blood is not immediately available.
Burn & Sepsis Treatment: Helps in fluid replacement and circulatory support.
