Plasma Expanders : Definition, Example, Uses, Indications, Side Effects, Contraindications, & Interactions
Definition
- Plasma expanders are high molecular weight (HMW) substances which exert colloidal osmotic (oncotic) pressure, and when infused i.v. retain fluid in the vascular compartment.
Indications
They are used to correct hypovolemia due to loss of plasma/blood.
- Primarily as substitutes for plasma in conditions where plasma has been lost or has moved to extravascular compartment, e.g. in burns, hypovolemic and endotoxin shock, severe trauma and extensive tissue damage.
- Used as a temporary measure in cases of whole blood loss till the same can be arranged: but they do not have 02 carrying capacity.
Properties
A desirable plasma expander should have following properties:
- It should exert oncotic pressure comparable to plasma.
- It should remain in circulation and not leak out in tissues, or be too rapidly disposed.
- It should be pharmacodynamically inert.
- It should not be pyrogenic or antigenic.
- It should be stable, easily sterilizable and cheap.
- It should not interfere with grouping and cross-matching of blood.
Classification
Human plasma or reconstituted human albumin would seem to be the best. However, synthetic colloids are more often used because the human plasma carries risk of transmitting serum hepatitis, AIDS, etc., and the reconstituted human albumin is expensive.
Substances used are:
- Human Albumin
- Hydroxyethyl starch Dextran (HES); (Hetastarch)
- Degraded gelatin polymer (Polygeline)
- Polyvinylpyrrolidone (PVP)
Contraindications
- Severe anaemia
- Cardiac failure
- Pulmonary edema
- Renal insufficiency
