Third space is FICTIONAL

For decades, the 'third space' was looked upon as an actively consuming compartment. Therefore, perioperative fluid regimens were traditionally based on a generous replacement of this assumed primary loss, in addition to deficits due to insensible perspiration and fasting. The practical consequence was an extremely positive fluid balance in order to maintain blood volume during major surgery. Whereas the insensible perspiration and the preoperative deficits are in fact often negligible, and the third space appears to be only a fictional construct, the excess fluid most likely accumulates interstitially...