Patterns of electrolyte excretion in edema loss without the use of diuretics.

DURING the loss or gain of edema the composition of the extracellular fluid remains remarkably constant despite the large ehanges in volume. A number of studies have indicated that the renal excretion of body water and electrolytes does not completely aceount for this constancy. In studies of edema loss, electrolytes and water were not lost in the same proportions that exist in extraeellular fluid or in a combination of extracellular and intracellular fluids.1-6 Sodium depletion and subsequent sodium replacement, in both edematous and nonedematous patients, produced changes in body sodium without proportional changes in the extracellular water.4 7-10 Sodium was retained by pre-edematous patients before edema appeared, and by post-edematous patients after the edema was lost.1"-'3 These studies do not necessarily contradict the idea that edema is excess extracellular fluid but indicate that, during the loss or gain of edema, sodium and water are not excreted or retained in the same proportion as they exist in extracellular fluid. Few balance studies were found in which all the edema of congestive heart failure was lost without the use of diuretics. The present report is of 15 edematous male patients studied on a metabolic ward who lost all of their edema on a regimen of bed rest and a fixed, low-sodium diet. The net urinary balance of sodium, potassium, and chloride has been related to weight change, which was used as the measure of change of body water. In all of the studies presented here, the loss of sodium per kilogram of weight loss was less than the concentration of sodium in extracellular fluid. There were two patterns of edema loss; in