Colloid osmotic pressure of plasma replacement fluids

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Pharmacology

Background:

• Colloid osmotic pressure (COP) is crucial for fluid balance.
• Plasma replacement fluids are vital in medical treatments.
• Understanding the COP of these fluids is essential for clinical efficacy.

Purpose of the Study:

• To measure and compare the colloid osmotic pressure (COP) of various frequently used plasma replacement fluids.
• To evaluate the impact of concentration on the COP of human albumin solutions.
• To assess the suitability of different fluids for accurate COP measurement.

Main Methods:

• Colloid osmometry was employed to measure COP.
• Solutions tested included human albumin, fresh donor plasma, dextrans, Ringer-Dextran, gelatin, and hydroxyethyl starch (HES).
• Measurements were compared against normal human serum values.

Main Results:

• 4% human albumin had half the COP of normal serum; 20% human albumin had eight times higher COP.
• Increasing albumin concentration 14-fold exponentially increased COP.
• Fresh plasma was ~30% below normal serum due to dilution.
• Dextran 70 and Ringer-Dextran 60 showed higher COP than normal serum.
• Dextran 40 and gelatin were unsuitable for measurement due to leakage.
• HES solutions exhibited a wide range of COP, from half to three times that of normal serum.

Conclusions:

• Human albumin solutions' COP is highly dependent on protein concentration.
• Dilution affects the COP of fresh donor plasma.
• Dextran and HES solutions present varied COP profiles.
• Accurate COP measurement is critical for selecting appropriate plasma replacement fluids.