Third spacing of fluids

In human physiology, extracellular fluids are distributed between the interstitial compartment (i.e. tissue) and intravascular compartment (i.e. plasma) in an approximately 60%-40% ratio. Third spacing was the physiological concept that body fluids may collect in a "third" body compartment that isn't normally perfused with fluids. For example, with severe burns, fluids may pool in the burn site and cause depletion of the fluids in the first and second compartments. With pancreatitis, fluids may "leak out" into the peritoneal cavity, also causing depletion of the first and second compartments. Clinically, it is common that the extent of "third spacing" is unknown, and therefore it served more as a theoretical concept for problem-solving rather than a concrete value.

Additional recommended knowledge

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Essential Laboratory Skills Guide

See also

Total body water

References

Redden M, Wotton K (2002). "Third-space fluid shift in elderly patients undergoing gastrointestinal surgery: Part 1: Pathophysiological mechanisms". Contemporary nurse : a journal for the Australian nursing profession 12 (3): 275-83. PMID 12219956. Retrieved on 2007-07-10.