Plasma Volume (via Osmotic Expansion)

Plasma volume refers to the total volume of plasma within the circulatory system. Osmotic expansion of plasma volume is a physiological process where an increase in osmotic pressure draws water into the vascular compartment from surrounding tissues, thereby increasing intravascular fluid content. This process is primarily driven by increased concentrations of plasma proteins, especially albumin, or the administration of osmotic agents. Clinically, osmotically mediated plasma volume expansion is critical for restoring normovolemia, managing hypovolemic shock, and supporting cardiovascular stability. It also plays a role in physiological adaptation following endurance training.

Increased intravascular osmolality/oncocity draws interstitial/tissue fluid into vasculature