Blood gas and pH changes during glucose infusion in the fetal sheep

Constant glucose infusions to the sheep fetus in utero with the use of the chronic catheterized preparation produced a significant improvement in fetal blood gases and pH (pH, 7.37 ± 0.02 vs. 7.42 ± 0.01; Po2, 14 ± 1.4 vs. 19 ± 1.5 mm. Hg; and Pco2, 58 ± 1.5 vs. 44 ± 1.7 mm. Hg; mean ± S.E.M. of pre- and postinfusion values.) Similar changes were not observed after an acute intravenous-bolus injection of glucose. These results may be explained on the basis of improved circulatory and perfusion status of the fetal-placental unit when a sustained increase in fetal blood glucose level was achieved by constant glucose infusion.