Parer J T
Clin Obstet Gynecol. 1980 Jun;23(2):565-82. doi: 10.1097/00003081-198006000-00025.
Fetal blood sampling with determination of pH and base excess is a valid and useful supplement to continuous FHR monitoring. When used in conjunction with the conventional methods of FHR interpretation, FBS can improve the accuracy of determination of the truly asphyxiated fetus, having a potentially ominous FHR pattern. Thus, its use may postpone or prevent the unnecessarily expeditious delivery of fetuses who are in fact not asphyxiated. Despite this usefulness, FBS has diffused poorly into the great majority of obstetric services in the United States, primarily because of the minor, though real, technical inconveniences and analytic difficulties. Many defenders of FHR monitoring feel that its use without the availability of FBS is responsible for the overdiagnosis of fetal distress and the subsequent increase in cesarean section rates. There are two possible ways out of this dilemma. First is the development of a simple method of continuously recording fetal tissue pH. Though there are such devices, they do not yet satisfy the necessary criteria of facility and simplicity, but improvements may be expected within several years. A second approach is to improve the accuracy of FHR interpretation, either by the application of available knowledge or by improvement in the understanding of FHR through further investigation. As to the application of presently available knowledge, avoidance of overcalling the presence of fetal distress could be facilitated by universal acceptance of the high prognostic accuracy of normal FHR variability to predict a vigorous fetus, even in the presence of other so-called ominous FHR patterns. Only a small number of fetuses, probably less than 1% in most populations, have FHR patterns with absent or decreasing variability with periodic changes that cannot be ascribed to drugs or other nonasphyxial causes. Part of this small group may unnecessarily go to cesarean section for fetal distress in the absence of FBS, but its influence on overall cesarean section rates will be minor.
进行胎儿血样采集并测定pH值和碱剩余，是对连续胎儿心率监测的一种有效且有用的补充。当与传统的胎儿心率解读方法结合使用时，胎儿血样采集可以提高对真正窒息胎儿的判定准确性，这些胎儿具有潜在不良的胎儿心率模式。因此，其应用可能会推迟或避免对实际上并未窒息的胎儿进行不必要的快速分娩。尽管有此作用，但胎儿血样采集在美国绝大多数产科服务中的普及程度很低，主要是因为存在一些虽小但实际存在的技术不便和分析困难。许多支持胎儿心率监测的人认为，在无法进行胎儿血样采集的情况下使用该监测方法，是导致胎儿窘迫过度诊断以及随后剖宫产率上升的原因。摆脱这一困境有两种可能的方法。第一种是开发一种连续记录胎儿组织pH值的简单方法。虽然有这样的设备，但它们尚未满足便捷性和简易性的必要标准，但预计在几年内会有所改进。第二种方法是通过应用现有知识或通过进一步研究提高对胎儿心率的理解，来提高胎儿心率解读的准确性。至于应用现有知识，普遍接受正常胎儿心率变异性对预测活力良好胎儿具有较高的预后准确性，即使存在其他所谓的不良胎儿心率模式，也有助于避免过度判定胎儿窘迫的存在。在大多数人群中，只有少数胎儿，可能不到1%，其胎儿心率模式表现为变异性缺失或降低，并伴有周期性变化，且无法归因于药物或其他非窒息性原因。在没有胎儿血样采集的情况下，这一小部分胎儿中的部分可能会因胎儿窘迫而不必要地接受剖宫产，但它对总体剖宫产率的影响将很小。
