In 1628 William Harvey introduced his concept ofthe human circulation. Although a lot of studies concerning the fetal circulation were done before it was not until the 1930s that Barcroft (1934, 1939) and associates performed radiograpbic studies on the feta! goal and lamb to establish the feta! circulation. Later in 1964 Lind, Stern and Wegelius used cine-angiographic studies to describe the human fetal circulation. Volume flow measurements were already carried out in 1884 by Cohnstein and Zuntz using a stromuhr in an umbilical artery. In 1949 Cooper, Greenfield and Huggett made their measurements of the umbilical blood flow at different gestational ages in the fetal sheep using a veneus plethysmograph. A variety of methods foliowed each other, such as density flowmeter, the velodyne flowmeter, the cannulated type of electromagnetic flowmeter and the cuff electromagnetic flowmeter. All these methods had several disadvantages. The major ones are exteriorisation of the fetus and the acute character of the flow measurements. Therefore, because of these disadvantages, techniques were developed with the possibility to study the fetus in chronic preparations after recovery from surgery (Berman et al, 1975). These chronic experiments however, may still not be indicative of the normal physiological state. The introduetion of ultrasonic Doppier techniques opened the possibility to measure blood flow non-invasively. Satomura (1959) published the first report on the use of ultrasonic Doppier equipment for the deleetion of human blood flow velocity. Since then the interest in the non-invasive detection ofhuman blood flow has been overwhelming. Nevertheless it took until the end of theseventies before the first reports appeared on the deleetion ofhuman feta! blood flow. FitzGerald et al (1977) introduced a methad for measurement of human urnhilical blood flow using continuous wave Doppler. A few years later pulsed Doppier was introduced for the measurement of urnhilical venous blood flow (Gill et al, 1978) and blood flow in the feta! deseending aorta (Eik-Nes et al, 1980). Blood flow in the feta! deseending aorta reflects cardiovascular function which in itself is an important souree of information about fetal well-being. To appreciate correctly the data obtained from these non-invasive flow measurements it is important to establish their reproducibility and to study the possible effects of internal and external stimuli since the latter may lead to misinterpretation of the results. The objectives of the present study were: I. to analyse the pitfalls related to the pulsed Doppier flow velocity measurement in the lower thoracic part of the feta! deseending aorta. 2. to establish the reprodueibility and normal val u esforblood flow veloeity, vessel diameter and volume flow in the lower thoraeie part of the feta! deseending aorta during the third trimester of pregnaney. 3. to analyse the influenee of external stimuli e.g. smoking and short term moderate exercise on these parameters. 4. to develop a more precise mcthod of recording of the vessel diameter changes in the lower thoraeie part of the feta! deseending aorta.

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N. Bom (Klaas) , J.W. Wladimiroff (Juriy)
Erasmus University Rotterdam
hdl.handle.net/1765/38628
Erasmus MC: University Medical Center Rotterdam

Pijpers, L. (1985, May 29). Blood flow in the human fetal descending aorta : a pulsed Doppler study. Retrieved from http://hdl.handle.net/1765/38628