MATERNAL ANESTHESIA AND FETAL CEREBRAL OXYGENATION

这项探索性/开发性资助的目的是使用新技术来确定和区分母体全身麻醉和区域麻醉对胎儿脑氧合的影响。维持胎儿大脑足够的氧气和营养供应在对怀孕雌性的操作中是最重要的。普遍的医疗实践鼓励在非产科相关手术和紧急剖宫产等手术中使用全身麻醉。然而，吸入剂（如异氟烷）对胎儿脑氧状态的影响所知相对较少。进一步说，我们可以提出局部麻醉（如表皮麻醉）可能因为麻醉定位于母体中枢神经系统而降低了对胎儿的影响。然而，这种益处可能会被母亲的低血压所抵消，而对胎儿的影响是测量氧水平的不可行性。为此，我们正在开发一种方法（近红外光谱；NIRS）来连续测量怀孕绵羊子宫内胎儿脑氧合。近红外光谱装置是专门为子宫内动物实验设计的。目前，我们已经通过测量胎儿羊脑氧合的变化来验证我们的近红外光谱方法，以响应脐带阻塞产生的全身氧水平降低。根据目前的建议，我们计划进一步优化我们的技术，应用它来回答一个临床相关的问题：母体麻醉是否会改变胎儿的脑氧合？本研究的完成将提供关于母体麻醉对胎儿脑氧合和健康影响的新信息。此外，这项研究将产生临床相关的数据，这将对麻醉医师、产科医生和普通外科医生有重大的兴趣，他们会遇到胎儿或腹部窘迫的孕妇。预计这些研究的结果将用于进一步制定和完善妊娠期间麻醉使用的护理标准。这些结果也将验证我们的近红外光谱方法，并将允许我们改进优化技术，并开发适当的分析工具来定量评估所得的近红外光谱数据。最后，该结果将作为一项长期结果研究的基础，旨在确定在胎儿窘迫发作、母体手术和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.