MATERNAL ANESTHESIA AND FETAL CEREBRAL OXYGENATION

这项探索性/发展性赠款的目标是使用新技术来确定和区分母亲全身麻醉和区域麻醉对胎儿脑氧合的影响。在操作怀孕女性的过程中，维持足够的氧气和营养物质供应给胎儿大脑是最重要的。目前的医学实践鼓励在非产科相关手术和紧急剖腹产等手术中使用全身麻醉。然而，关于吸入剂(如异氟醚)对胎儿脑氧状态的影响，人们知之甚少。推而广之，人们可以提出局部技术(如表皮麻醉)可能由于麻醉剂定位于母体中枢神经系统而减少了对胎儿的影响。然而，这种好处可能会被母亲的低血压所抵消，就胎儿的影响而言，就是测量氧气水平的不切实际。为此，我们正在开发一种在怀孕绵羊体内连续测量胎儿脑氧合的方法(近红外光谱；NIRS)。近红外光谱装置是专门为子宫内动物实验而设计的。目前，我们已经通过测量胎羊脑氧合的变化来验证我们的NIRS方法，以响应脐带闭塞所产生的全身性氧气水平的下降。根据目前的建议，我们计划通过应用该技术来进一步优化我们的技术，以回答一个与临床相关的问题：母体麻醉是否会改变胎儿的脑氧合？这项研究的完成将产生关于母体麻醉对胎儿脑氧合和幸福感的影响的新信息。此外，这项研究将产生临床上相关的数据，麻醉师、产科医生和普通外科医生对胎儿或腹部窘迫的产妇非常感兴趣。预计这些研究的结果将被用于进一步发展和完善孕期麻醉剂使用的护理标准。这些结果还将验证我们的近红外光谱方法，并将使我们能够改进和优化技术，并开发适当的分析工具来对结果的近红外光谱数据进行定量评估。最后，这些结果将作为长期结果研究的基础，旨在确定在胎儿窘迫、产妇手术以及最终胎儿手术期间使用的最佳麻醉参数。

The goal of this exploratory/developmental grant is to use novel technology to determine and differentiate the effects of maternal general anesthesia to those of regional anesthesia on fetal cerebral oxygenation. Maintaining an adequate supply of oxygen and nutrients to the fetal brain is of primary importance during manipulations of the gravid female. Prevailing medical practice encourages the use of general anesthesia for such procedures as non-obstetric related surgery and emergent cesarean section. However, relatively little is known about the effects of inhalational agents (e.g. isoflurane) upon fetal cerebral oxygen status. By extension, one could propose that regional techniques (e.g. epidermal anesthesia) might have reduced fetal effects because of the localization of anesthetic to the maternal CNS. However, this benefit could be counter-acted by the maternal hypotension and with respect to fetal effects, is the impracticability of measuring oxygen levels. To that end, we are developing a means (near infrared spectroscopy; NIRS) of continually measuring in utero fetal cerebral oxygenation in pregnant sheep. An NIRS device was designed specifically for in utero animal experimentation. Currently, we have validated our NIRS methodology by measuring changes in fetal sheep cerebral oxygenation in response to systemic decreases in oxygen levels produced by umbilical cord occlusion. With the present proposal, we plan to further optimize our technology by applying it to answer a clinically-relevant question: Does maternal anesthesia alter fetal cerebral oxygenation? Completion of this study will yield new information regarding the effects of maternal anesthesia on fetal cerebral oxygenation and well-being. In addition, this research will produce clinically relevant data that will be of significant interest to anesthesiologists, obstetricians, and general surgeons who are presented parturients with fetal or abdominal distress. It is expected that the results of these studies will be used to further develop and refine standards of care for anesthetic use during pregnancy. These results will also validate our NIRS methodology, and will allow us to refine-optimize the technology and to develop the appropriate analysis tools to quantitatively evaluate the resultant NIRS data. Finally, the results will serve as the basis for a long-term outcome study designed to identify the optimal anesthetic parameters to be used during an episode of fetal distress, maternal surgery, and eventually fetal surgery.