These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Phasic blood flow patterns in the superior and inferior venae cavae and umbilical vein of fetal sheep.
    Author: Reuss ML, Rudolph AM, Dae MW.
    Journal: Am J Obstet Gynecol; 1983 Jan 01; 145(1):70-8. PubMed ID: 6849346.
    Abstract:
    Measurements of phasic blood flow in the inferior and superior venae cavae and umbilical vein of fetal sheep (gestational age, 121 to 140 days) were made with chronically implanted electromagnetic flow transducers. In the venae cavae blood flow was inversely related to phasic changes in venous and/or intrathoracic pressure. During fetal apnea a forward surge of flow occurred during ventricular systole (systolic surge) and ventricular diastole (diastolic surge). Slower fetal heart rates were associated with a more prominent diastolic surge. Reductions in afterload caused by acetylcholine administration augmented the peak diastolic venous flow. In contrast, increased afterload caused by hypoxia and norepinephrine administration was associated with increased peak systolic flow. During regular fetal breathing movements the phasic flow pattern was determined largely by the respiratory cycle with the effect of the cardiac cycle superimposed. There was minimal venous pulsation in the intra-abdominal umbilical vein, compared with that of the intrathoracic venae cavae of the apneic fetus. Our findings demonstrate that fetal systemic vascular resistance profoundly influences right atrioventricular filling patterns.
    [Abstract] [Full Text] [Related] [New Search]