Title: 394: Effects of maternal hyperoxygenation on fetal pulmonary circulation and on blood flow patterns in the ductus venosus in normal third-trimester fetuses
Abstract: The aims of the present study were to determine whether maternal hyperoxygenation affects human fetal pulmonary circulation, ductus venosus and umbilical arterial blood flow and flow in the middle cerebral arteries. Nine pregnant women with normal singleton pregnancy (mean gestational age 34.7+3.2 weeks) participated in the study. Doppler blood flow velocity waveforms were obtained from the umbilical and the middle cerebral arteries, the main pulmonary artery, the proximal right pulmonary artery and from the ductus venosus. The pulsatility indices (PI) were calculated for the pulmonary, umbilical and middle cerebral arteries. Peak systolic velocity was determined in the middle cerebral artery and the PI value for veins was calculated for the ductus venosus. Following baseline measurements, each woman received 70% humidified oxygen for at least 8 minutes. Doppler measurements were then repeated. Maternal hyperoxygenation caused a significant decrease in PI values in the main pulmonary (3.07+0.54 before and 2.28+0.3 after O2, p<0.01) and in the right pulmonary artery (2.73+0.32 before and 2.02+0.17 after O2, p<0.01). The PI in the umbilical and the middle cerebral arteries did not change significantly following hyperoxygenation. There was no significant change in the peak systolic velocity in the middle cerebral artery after oxygen administration. The pulsatility index in the ductus venosus significantly decreased following hyper-oxygeneation (from a baseline of 0.79+0.28 to 0.53+0.22, p< 0.02). This study shows that in normal pregnancy hyperoxygenation abolishes the relative vasoconstriction in fetal pulmonary vessels during the third trimester and that oxygen tension in the fetus has a role in the regulation of the fetal pulmonary circulation. The results also demonstrate a close relationship between fetal oxygenation and ductus venosus velocity waveforms. These findings may be useful in monitoring fetal oxygen levels in a non-invasive manner and help detect fetal hypoxemia in high-risk pregnancies.
Publication Year: 2011
Publication Date: 2011-12-29
Language: en
Type: article
Indexed In: ['crossref']
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