Plasma Volume and Plasma Colloid Osmotic Pressure

Abstract

Ten different specimens of plasma were concentrated by ultrafiltration to a colloid osmotic pressure (COP) of 50–80 cm H₂O, then diluted by the addition of 0.15 M sodium chloride solution. The relationship between the changes in volume (V) and COP satisfy the equation V: COP^0.687 = K. Post-operatively, for patient groups with the same change in the circulating amount of protein, the accompanying changes in plasma volume (PV) and COP did not vary significantly from the equation. K is a functional parameter expressing the total colloid osmotic capacity. It is determined by the amount and composition of the intravascular protein mass.

Key Words:

• Blood volume
• colloid osmotic pressure
• plasma