extravascular fluid (3rd space)

Extracellular fluid outside of the vascular compartment. Sequestration of fluid in this compartment may occur. The fluid is effectively lost from the vascular compartment & hypovolemia can result despite the fluid in this 3rd space. Examples of extravascular fluid include: 1) peritoneal cavity (hepatic cirrhosis, peritonitis) 2) retroperitoneal space (acute pancreatitis) 3) subcutaneous tissues (burns) 4) bowel lumen (intestinal obstruction) 5) pleural space (pleural effusion)

References

Harrison's online, http://www.harrisononline.com