Oncotic pressure
Chapter: 2
The osmotic pressure created by colloids (mainly plasma proteins) that are normally retained within the vascular system. Oncotic pressure nearly offsets the hydrostatic pressure that acts to drive fluid out of vessels into the extravascular space. The result is that small amounts of fluid cross the vascular barrier, which are then transported back to the blood via the lymphatics. A decrease in oncotic pressure can be a cause of non-inflammatory edema (see separately).