Plasma volume expansion via osmotic shift and increased oncotic pressure

Plasma volume expansion refers to an increase in the liquid component of blood (plasma) through osmotic shift and increased oncotic pressure. Osmotic shift involves water movement into the vascular compartment driven by solute concentration differences, primarily sodium. Increased oncotic pressure elevates plasma protein concentrations, particularly albumin, drawing water into the bloodstream. This process improves cardiac output, muscle perfusion, and thermoregulation, occurring physiologically in pregnancy, exercise acclimation, and rehydration.

Other names

HypervolemiaPlasma volume loading

Osmotic shift of fluid into the vasculature and/or retention of fluid within the vasculature due to increased colloid osmotic pressure.