A STUDY OF THE ACID‐BASE BALANCE OF FETAL SHEEP AND GOATS

Abstract

By means of indwelling plastic catheters the pCO2, pH and bicarbonate levels of the maternal and fetal plasmas have been compared in sheep and goats by repeated sampling during periods up to 24 hr. Comparisons have been made in “steady state” conditions, as well as during and following NH4Cl infusion of the mother. The results demonstrate: (1) that the pCO2 of the blood of the umbilical artery is about 20 mm. Hg higher than the maternal arterial pCO2 in “steady state” conditions; (2) that this difference remains relatively stable despite wide variations in the pCO2 of the maternal arterial blood; (3) that the bicarbonate level of the fetal plasma is virtually independent of the maternal over a 24‐hr. period; and (4) in some circumstances the pH's of the maternal and fetal bloods may change in opposite directions. © 1960 The Physiological Society