BLOOD VOLUME AND PLASMA ELECTROLYTE CHANGES IN THE DEHYDRATION OF INFANTS

Abstract

Infants (11) suffering from dehydration associated with diarrhea were subjected to simultaneous determination of total blood volume and serum electrolyte concentration, both during dehydration and after recovery. In acute dehydration some patients showed no essential change in total blood volume, while others showed a 20% diminution of the recovery value. When this reduction was marked, it involved principally the plasma fraction, in 1 instance to the extent of 30%. There was no close parallelism between the diminution of plasma volume and (1) the degree of dehydration of the subcutaneous tissues as determined by clinical criteria or (2) the severity of toxic symptoms. Most of the patients showed during dehydration a decrease in the serum concentration of total fixed base, chloride, and bicarbonate; but the degree of acidosis, as measured by the serum bicarbonate concentration, could not be correlated with changes in blood or plasma volume, since the patient whose plasma loss was greatest for the whole series had a higher bicarbonate concentration on admission than after recovery. Before treatment had been given, the lowering of the total plasma electrolyte content was sometimes even greater than the loss of plasma water, when measured as percentage deviations from the presumably normal values found after recovery. Protein was often included among the electrolytes lost from the plasma during dehydration, so that the composition of the fluid leaving the circulation was comparable to that of plasma of normal protein and bicarbonate content but concentrated in respect to fixed base and chloride. As a check on the assumption that the 2nd set of determinations, made after recovery from dehydration but not always at a time of complete clinical recovery, represented normal values for the individual studied, the figures obtained during dehydration were compared with normal values obtained by applying the same technical procedures to healthy infants. This comparison substantiated the results already expressed.