The buildup of blood-derived fluid in body cavities, intestinal regions, or other regions of the body where there is often minimal fluid is referred to as “third space”.
The term "third spacing" is no longer used to describe how biological fluid moves from the blood into the spaces between the cells.
Third spacing occurs when intravenous fluid switches from blood circulation to the interstitial space—the space between cells in organs and tissues.
This process can possibly lead to issues such as hypotension, reduced cardiac output, and edema.