Materno-fetal biochemical, circulatory and pathological changes following experimentally-induced uremia in the pregnant dog.

Abstract

Bilateral ureteral ligations and catheterization of carotid artery, uterine vein and superior vena cava were performed on 17 term-pregnant dogs. Daily blood analyses revealed consistent increases in plasma potassium, plasma osmolarity and blood urea, and constant decreases in plasma chloride and blood pH. Fetal blood sampling at the terminal stage of the maternal uremia revealed similar or realtively augmented biochemical changes when compared with those of maternal blood. Fetal blood PCO2 was found to be elevated, suggesting an existency of both respiratory and metabolic acidosis. Maternal blood pressure demonstrated terminal hypotension with well-maintained or increased pulse pressure, together with marked bradycardia. Maternal ECG demonstrated typical changes, such as disappearance of P waves, widened bizzare QRS, tall narrow T and questionable Q-T elongation. Fetal ECG demonstrated less significant changes despite marked blood biochemical changes. Typical pathologic changes associated with metabolic uremia were observed in maternal organs. In the fetal kidneys, widening of Bowman's space and hydropic, degenerations of tubules were found. It was concluded that the fetus had a tolerance or decreased sensitivity to the changes associated with metabolic acidosis, hyperkalemia and uremia, when compared to the maternal animal.