Third spacing

Third spacing

"Third spacing" is the abnormal accumulation of fluid into an extracellular and extravascular space. In medicine, the term is often used with regard to loss of fluid into interstitial spaces, such as with burns or edema, but it can also refer to fluid shifts into a body cavity (transcellular space), such as ascites and pleural effusions. With regard to severe burns, fluids may pool on the burn site (i.e. fluid lying outside of the interstitial tissue, exposed to evaporation) and cause depletion of the fluids. With pancreatitis or ileus, fluids may "leak out" into the peritoneal cavity, also causing depletion of the intracellular, interstitial or vascular compartments.