Why plasma crystal osmotic pressure decrease?

Plasma osmotic pressure (OP) decrease due to several factors:

Hypoalbuminemia: Albumin is the major protein constituent of the blood plasma and contributes significantly to osmotic pressure. Conditions such as severe liver disease, malnutrition, nephrotic syndrome, and protein-losing enteropathy can lead to low albumin levels (hypoalbuminemia), resulting in decreased plasma osmotic pressure.

Overhydration: Excess fluid intake or impaired fluid excretion can cause overhydration, diluting the plasma and reducing its concentration of solutes, including proteins and electrolytes. This dilution effect lowers the osmotic pressure of the plasma.

Loss of electrolytes: Electrolytes, such as sodium, potassium, and chloride ions, play a crucial role in maintaining plasma osmotic pressure. Abnormal losses of these electrolytes through excessive sweating, diarrhea, vomiting, or certain medications can deplete their levels in the plasma, leading to a decrease in osmotic pressure.

Increased capillary permeability: In conditions where the integrity of the capillary walls is compromised, such as in inflammation, burns, or sepsis, there may be an increased leakage of fluid and proteins from the capillaries into the surrounding tissues. This loss of fluid and proteins from the circulating blood volume decreases the plasma osmotic pressure.

Transfusion of hypotonic or colloid-poor solutions: Transfusion of intravenous fluids that are hypotonic (lower solute concentration) or deficient in colloids (like albumin) can directly reduce the osmotic pressure of the plasma.