Plasma Volume Expanders

Definition of Plasma Volume Expanders

• Plasma Volume Expanders are fluids used to restore and maintain intravascular volume in patients experiencing hypovolemia (low blood volume), such as during shock, trauma, burns, or surgery.
• They work by increasing osmotic pressure, which helps retain fluid within the vascular compartment.

Types of Plasma Volume Expanders:

1. Crystalloids:

• Normal Saline (0.9
  • Composition: Sodium chloride.
  • Use: Volume replacement in hypovolemia, shock, resuscitation.
  • Advantages: Widely available, inexpensive.
  • Disadvantages: Can cause hyperchloremic metabolic acidosis with large volumes.
• Lactated Ringer’s Solution:
  • Composition: Sodium, chloride, potassium, calcium, and lactate.
  • Use: Similar to normal saline; preferred in surgery due to electrolyte composition.
  • Advantages: More physiologic electrolyte balance; buffer provided by lactate.
  • Disadvantages: Not suitable for patients with liver dysfunction (impaired lactate metabolism).
• Dextrose Solutions (e.g., D5W):
  • Use: Maintenance fluids; not effective as volume expanders since dextrose is rapidly metabolized.
  • Advantages: Provides calories; used in combination with other fluids.
  • Disadvantages: Limited volume-expanding capability.

2. Colloids:

• Albumin:
  • Mechanism: Natural protein that maintains oncotic pressure.
  • Use: Hypovolemia, burns, liver cirrhosis, nephrotic syndrome.
  • Advantages: Long intravascular persistence.
  • Disadvantages: Expensive; risk of allergic reactions.
• Hydroxyethyl Starch (HES):
  • Use: Volume resuscitation in hypovolemia and shock.
  • Advantages: Effective plasma volume expansion.
  • Disadvantages: Risk of coagulopathy, renal impairment, allergic reactions.
• Dextrans:
  • Use: Volume expansion, prevention of surgical adhesions (historical use).
  • Advantages: Effective plasma volume expansion.
  • Disadvantages: Risk of anaphylaxis, coagulopathy, hyperglycemia.
• Polygeline (Haemaccel):
  • Use: Volume replacement in hypovolemia.
  • Advantages: Effective volume expansion.
  • Disadvantages: Less commonly used due to availability of better alternatives; risk of allergic reactions.

Clinical Considerations:

• Choice Between Crystalloids and Colloids: Dependent on clinical scenario, patient condition, and cost considerations. Current trends favor crystalloids due to safety profile.
• Fluid Overload Risk: Especially with colloids; requires careful monitoring.
• Electrolyte Balance: Crystalloids can affect electrolyte levels; selection based on patient needs is crucial.
• Allergic Reactions: More common with certain colloids; premedication may be necessary.

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