Indwelling plastic catheters in developmental physiology

Abstract

Science, the observation, investigation, and explanation of natural phenomena, is both dependent on methodology and, in turn, is a stimulus to advances in technology. For developmental physiology, the technique of chronic catheterization inaugurated a new era in investigating and gaining an understanding of the biology of the developing fetus and newborn infant. In this report by Meschia et al on the use of chronic catheterization for a period of several weeks to obtain samples for measurement of blood gases andmetabolites, Figure 4 shows the percent oxyhemoglobin saturation of umbilical venous and arterial blood of fetal lambs from days 87 to 148 gestation.Figure 5 shows these values in the fetal goat from 97 to 152 days gestation. Contrary to the accepted belief at that time that fetal O2 tension and oxyhemoglobin saturation decreased near-term, the authors observed no significant changes in these levels as a function of gestational age. The 4 decades after this report have witnessed several thousand reports on important aspects of fetal metabolism. These studies have contributed enormously to a better understanding of the biology of the developing fetus.