Extracellular fluid deficit following operation and its correction with Ringer's lactate. A reassessment.

The changes in extracellular fluid volume (ECV) in two groups of surgical patients, one receiving Ringer's lactate solution intraoperatively and the other receiving only dextrose and water, were assessed. A deficit in the ECV, as measured by radioactive sulfate, of 1.9 +/- 0.8 l (p less than 0.003) compared to the preoperative volume was found in the dextrose group. This was accompanied by a decrease in the mean creatinine clearance (-13% p less than 0.01), the mean urinary sodium excretion (-57% p less than 0.05), and the mean rate of clearance of the sulfate tracer (-18% p less than 0.01). The use of intraoperative Ringer's lactate (1660 cc +/- 96 cc) resulted in no change in the ECV, an increase in the mean creatinine clearance (+10% p less than 0.05), and no change in sodium excretion or tracer clearance. As a result of these findings, it appears that postoperative sodium retention is a physiologic response to a decreased ECV, which can be prevented by the administration of Ringer's lactate.