Skarsgard E D, Bealer J F, Meuli M, Adzick N S, Harrison M R
Fetal Treatment Center, University of California, San Francisco 94143-0570, USA.
J Pediatr Surg. 1995 Aug;30(8):1165-8. doi: 10.1016/0022-3468(95)90013-6.
Application of video-endoscopic surgery to the gravid uterus provides a new treatment option for the fetus with a correctable congenital anomaly. "Fetendo" surgery requires temporary enlargement of the uterine cavity to create a working space. Volume expansion of the amniotic space raises intrauterine pressure, which could increase placental vascular resistance and thereby reduce placental blood flow. To test this hypothesis, the authors developed a fetal sheep model to examine the relationship between insufflating pressure and flow in the placental circulation. Fetoplacental blood flow was measured via ultrasonic flow probes placed around the fetal common umbilical artery and the maternal uterine artery in five anesthetized 120-day-gestation ewes. Invasive feto-maternal monitoring permitted synchronous measurement of fetal mean arterial pressure, fetal central venous pressure, maternal mean arterial pressure, amniotic pressure, and fetal oxygen saturation, with calculated values for fetal and maternal placental vascular resistance. Amniotic pressure was raised from 10 mm Hg to 40 mm Hg in 5-mm Hg increments by a combination of saline amnioinfusion and external uterine compression. At amniotic pressures of 20 mm Hg or less, placental blood flow was preserved; however, elevation of amniotic pressure above 20 mm Hg resulted in a significant decrease in placental flow, with concomitant fetal hypoxia. The authors conclude that the relationship between intrauterine pressure, flow in the placental circulation, and fetal oxygen delivery must be considered when selecting intrauterine insufflation pressures for hysteroscopic intervention.
视频内镜手术应用于妊娠子宫为患有可矫正先天性异常的胎儿提供了一种新的治疗选择。“胎儿内镜手术”需要暂时扩大子宫腔以创造操作空间。羊膜腔容积扩张会升高子宫内压力，这可能会增加胎盘血管阻力，从而减少胎盘血流。为了验证这一假设，作者建立了一个胎羊模型来研究充气压力与胎盘循环血流之间的关系。通过将超声血流探头置于5只妊娠120天、处于麻醉状态的母羊的胎儿脐动脉和母羊子宫动脉周围，来测量胎儿 - 胎盘血流量。有创的胎儿 - 母体监测允许同步测量胎儿平均动脉压、胎儿中心静脉压、母体平均动脉压、羊膜腔压力和胎儿血氧饱和度，并计算胎儿和母体胎盘血管阻力值。通过羊膜腔内注入生理盐水和外部子宫压迫相结合的方式，将羊膜腔压力以5 mmHg的增量从10 mmHg升高至40 mmHg。在羊膜腔压力为20 mmHg或更低时，胎盘血流得以维持；然而，当羊膜腔压力升高超过20 mmHg时，胎盘血流显著减少，并伴有胎儿缺氧。作者得出结论，在选择宫腔镜干预的子宫内充气压力时，必须考虑子宫内压力、胎盘循环血流和胎儿氧输送之间的关系。
