Response to Rapid Volume Expansion During the Postnatal Period

The relationship between V, CIN, and CPAH before and during diuresis as a result of infusion of D5W is shown in Figs 3 and 4; the relationship between V, osmolal clearance (COSM), and free water clearance (CH2O) is represented in Figs 5 and 6. The various clearances have been plotted against urine volume and compared with the regression lines for 17 infants (including seven in this paper) during the first three hours of life and prior to receiving an infusion.4 Despite a considerable scatter of data, there is no significant difference in the various correlations before and after infusion. A small decrease in fractional water reabsorption was observed after infusion, but not during spontaneous diuresis. No change in fractional osmolal reabsorption was observed during either spontaneous or infusion diuresis (Tables 2 and 3). In Table 4 the mean changes in the various measurements of renal function measured with infusion are compared with those occurring during spontaneous diuresis in the same infants. Again, except for the percentage of water reabsorbed after the infusion, there were no differences in the responses with the spontaneous diuresis compared to those observed after the infusion. See Images in the PDF File See Images in the PDF File See Images in the PDF File See Images in the PDF File See Table in the PDF File DISCUSSION Newborn infants during the first four hours of life are capable of having a prompt diuresis in response to an infusion of isotonic glucose. This diuresis is accompanied by an increase in renal plasma flow (RPF) and glomerular filtration rate (GFR).