Distribution of water and electrolytes in normal and thermally damaged skin

The alterations in contents of Na, K and water in thermally injuried explants of guinea-pig flank skin involve changes in both the cells and the interstitial material of the tissue. A full interpretation of the distribution of such changes can only be obtained if the volumes of cellular and extracellular fluid are known. This work examines the techniques of measuring extracellular fluid volume using 14C-inulin and 51Cr EDTA. Although it was found that the inulin preparation was excluded from a considerable part of the extracellular fluid of the skin explants, the space which it defined altered with increasing severity of thermal damage. The relationship of the inulin space with total water and with 51Cr EDTA space, which probably measures the total extracellular volume, provides an insight into the possible importance of changes in the nature of connective tissue in trauma. Alterations in fluid and cation balance between cells and their environment have been discussed in relation to increasing thermal damage. A clear sequence of events following the onset of the injury can be observed.