Sodium Recovery from Normal and Edematous Lungs Studied by Indicator Dilution Curves

Abstract

We attempted to measure sodium and water spaces in the lungs before and after pulmonary edema produced in dogs by increasing pulmonary capillary pressure or by alloxan. We employed a technique depending on the difference in transit times through the lungs of tritiated water or 24 Na + , with reference to an intravascular indicator. In the control measurements, there was virtually complete recovery of the sodium indicator, but in pulmonary edema there was a significant loss. It is possible that this represents distribution of some of the 24 Na + into an extravascular volume with an exit other than the pulmonary veins, but we would expect this to be accompanied by an equivalent amount of tritiated water. Since there was complete recovery of tritiated water in pulmonary edema, it seems more likely that the sodium loss represents binding by some extravascular locus and may be related to the extent of alveolar wall injury.