School of Women's and Children's Health, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia.
Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia.
Fetal Diagn Ther. 2021;48(9):651-659. doi: 10.1159/000517727. Epub 2021 Oct 28.
Maternal hyperoxygenation effects on fetal cerebral hemodynamics are largely unknown. This study aimed to determine efficacy and reliability of a validated power Doppler ultrasound (US) index, fractional moving blood volume (FMBV), at measuring fetal cerebral vasculature changes during maternal hyperoxia.
The fetal cerebral effects of 10 min of hyperoxygenation at 2 flow rates (52%/60% FiO2) were evaluated in women in their third trimester of pregnancy. 2D-US and 3D-US in a transverse plane were performed before, during, and following maternal hyperoxygenation with FMBV estimation performed offline.
Forty-five cases provided data for analysis. Mean intraobserver ICCs were 0.89 (3D-FMBV) and 0.84 (2D-FMBV). A significant difference in vascularity before and during and before and after 60% hyperoxia was observed (p < 0.05), whereas no significant differences were found at 52% hyperoxia (p > 0.05). Significant differences in vascularity were found between 2D-FMBV and 3D-FMBV (p < 0.01).
Measurement of fetal cerebral vascularity by 3D-FMBV and 2D-FMBV was highly reproducible. The differing cerebral vascular changes seen with 60% but not 52% FiO2 suggest a possible "threshold effect" that may have influenced prior studies. Further studies are needed to assess cerebral effects of maternal hyperoxygenation on compromised fetuses.
母体高氧对胎儿脑血流动力学的影响在很大程度上尚不清楚。本研究旨在确定经过验证的功率多普勒超声（US）指数——分数移动血容量（FMBV），在测量母体高氧期间胎儿脑血管变化中的有效性和可靠性。
本研究评估了在妊娠晚期的女性中，10 分钟的高氧（52%/60% FiO2）对胎儿大脑的影响。在进行母体高氧时，使用二维 US 和三维 US 在横切面进行检查，并离线进行 FMBV 估计。
45 例患者提供了用于分析的数据。观察者内的平均 ICC 为 0.89（3D-FMBV）和 0.84（2D-FMBV）。在 60%高氧前后和 52%高氧前后观察到血管密度存在显著差异（p<0.05），而在 52%高氧时未发现显著差异（p>0.05）。2D-FMBV 和 3D-FMBV 之间的血管密度存在显著差异（p<0.01）。
3D-FMBV 和 2D-FMBV 测量胎儿脑血管的方法具有高度的可重复性。60%FiO2 而不是 52%FiO2 时观察到的不同的脑血流变化提示可能存在“阈值效应”，这可能影响了之前的研究。需要进一步的研究来评估母体高氧对胎儿的脑影响。
