oncotic pressure การใช้

• Consequently, the intravascular oncotic pressure reduces relative to the interstitial tissue.
• The oncotic pressure on glomerular capillaries is one of the forces that resist filtration.
• The difference in the COP of the blood and tissue is called the oncotic pressure.
• This provides an oncotic pressure for ions to enter the vasa recta from the interstitium.
• Both these effects decrease the contribution of the oncotic pressure gradient to the net driving force.
• Because hydrostatic pressures in the tubules, interstitium and peritubular capillaries are normally equivalent, oncotic pressures govern flow.
• Because blood proteins cannot escape through capillary endothelium, oncotic pressure of capillary beds tends to draw water into the vessels.
• The oncotic pressure is in direct opposition with the hydrostatic pressure and tends to draw water back into the capillary by osmosis.
• The total oncotic pressure of an average capillary is about 28 mmHg with albumin contributing approximately 22 mmHg of this oncotic pressure.
• The total oncotic pressure of an average capillary is about 28 mmHg with albumin contributing approximately 22 mmHg of this oncotic pressure.
• Lymph capillaries have a greater internal oncotic pressure than blood capillaries, due to the greater concentration of plasma proteins in the lymph.
• Packed RBCs, plasma or whole blood should not be used solely for volume expansion or to increase oncotic pressure of circulating blood.
• The typical swollen abdomen is due to two causes : ascites because of hypoalbuminemia ( low oncotic pressure ), and enlarged fatty liver.
• It allows water to flow more freely and it reduces the colloidal or oncotic pressure difference by allowing protein to leave the vessel more easily.
• Because plasma proteins are virtually incapable of escaping the glomerular capillaries, this oncotic pressure is defined, simply, by the ideal gas law:
• Serum albumins are important in regulating blood volume by maintaining the oncotic pressure ( also known as colloid osmotic pressure ) of the blood compartment.
• It is necessary to understand the oncotic pressure as a balance; because the blood proteins reduce interior permeability, less plasma fluid can exit the vessel.
• Therefore, the concentration of these proteins tends to increase as the glomerular capillaries filtrate plasma, increasing the oncotic pressure along the length of a glomerular capillary.
• Early studies conducted in experimental animals showed that infusion of free haemoglobin caused also substantial increase in oncotic pressure because of its hyperosmolarity, coagulopathy, and hypertension.
• Protein-losing enteropathy may also occur, causing depletion of albumin, a blood protein, which may lead to peripheral edema caused by the lowered oncotic pressures.