EFFECTS OF LARGE LOADS OF ELECTROLYTES

Abstract

The effects of large electro'yte loads provided by adding various salts to a constant food intake were observed in two healthy infants on the basis of balance measurements found over a fore-period. The salts used were NaCl, NaHCO3, KCl and K-acetate. The balances found over the periods of load were corrected for unmeasured loss by a value derived from the observed fore-period balances and an estimation of actual retention for growth based on expected body weight gain in relation to age. The measurements of balance thus obtained are regarded as rough approximations. It is believed, however, that they permit a description of the following main features of effects of load. Adjustment of outgo to load was found to be a gradual process. Accumulation of surplus electrolyte in the body continued almost to the end of eight day periods of load and amounted to about 15% of initial body content. With the large retentions of Na produced by NaCl or by NaHCO3, extensive depression of K retention below the fore-period level was found. The inverse effect, reduction of Na retention in the presence of large gain of K, was observed in the KCl and K-acetate periods. Nitrogen retention was not disturbed by NaCl load and was found above the fore-period rate in the NaHCO3 and K-acetate periods but was extensively depressed by KCl. Using the balance data and measurements of the concentration of Na and Cl in the blood plasma, estimations of sodium shift were obtained by the method of Darrow. A large transfer of Na to the intracellular compartment was found in the NaHCO3 period and in the KCl period Na was extensively removed. These transfers of Na closely preserved the usual concentration of bicarbonate in the plasma in the presence of widely unequal retentions of Na and Cl. A considerable gain of intracellular Na was observed under the NaCl load, but no removal was found in the K-acetate period. Estimations of volume change of extracellular and of intracellular fluid are presented which illustrate the large effect of sodium shift in determining the distribution of body water accompanying electrolyte balance changes produced by load.