产科麻醉与镇痛新进展

New opinion on obstetric anesthesia and labor analgesia

产科全麻主要从母体和胎儿两个层面考虑,对母体考虑插管困难和防止返流误吸,对胎儿考虑麻醉及药物对胎儿和新生儿的影响。产妇是困难气道吗?经典观点认为产妇因肥胖、舌体肿大、咽喉、气管粘膜水肿等属于困难气道,但随着全球对困难气道的重视,解决困难气道用具丰富,大量的文献和临床实践并不认为产妇是困难气道(特别肥胖的产妇除外),但把产妇当做困难气道去对待还是有必要的。除了肌肉松弛剂外,目前常应用的麻醉药及相关用药都是很容易透过胎盘屏障的,所以,全麻药物的选择和剂量的控制很重要。药物作用时间更重要,一般认为麻醉诱导至胎儿娩出时间(I-D时间)<10～15min和子宫切开至胎儿娩出时间(U-D时间)<3min可有效防止药物对胎儿的影响。液体治疗可以很有效地防止剖宫产患者腰麻后低血压的发生率,胶体液优于晶体液。麻黄碱和去氧肾上腺素均可纠正低血压,但前者加重了胎儿酸血症的状况,所以,若母体心律不低,推荐应用去氧肾上腺素。血小板减少症是妊娠常见的合并症,总发生率约为7.6%,无论是何种类型的血小板减少,孕产妇事实上处于高凝状况,许多学者对这类产妇成功实施了硬膜外腔麻醉,认为产妇椎管内麻醉时对血小板计数的要求可适当放宽。血小板计数<50×109/L的产妇应摒弃椎管内麻醉,一律选择全身麻醉,技术不成熟的医疗单位可选择局部浸润麻醉。连续腰麻在妇产科麻醉与镇痛方面可能有令人鼓舞的发展。潜伏期分娩镇痛是近年来研究的热点,中外许多学者和学术机构认为潜伏期分娩镇痛是安全可行的。静脉分娩镇痛成为一种补充手段。镇痛后阴道器械助产率方面中外差异较大,原因仍需探究。连续蛛网膜下腔阻滞分娩镇痛是新思路。

There are two aspects of parturient and fetus need to be considered for obstetric general anesthesia. Difficult intubation, regurgitation and aspiration are needed to be considered for the parturient, the effect of anesthesia and drug on fetus and infant is also needed to be considered. Do the parturient have the difficult airway? From a classical point of view, obesity, tongue hypertrophy and throat edema of the parturient are classified into the difficult airway. But with more attention paid to the difficult airway from the whole world, there are more and more methods to solve the problem. It is considered that the pregnant don’t have the difficult airway on the evidence of many literatures and clinical practice (except particularly obesity). Nonetheless, it is necessary that the parturient should be considered as difficult airway patient. At present, the anesthetic and related drugs we used can easily cross the placenta except muscle relaxant. Therefore, the choice of anesthetic drugs and the dosage is very important. The acting time of drugs is much more important. It is generally acknowledged that the induction time to delivery time(I-D time) is less than 10 to 15 minutes and uterus cutting time to delivery time(U-D time) is less than 3 minutes can prevent the drug influence on fetus effectively. The rate of hypotension on cesarean section by spinal anesthesia can be avoided by transfusion treatment effectively. Colloidal solution is much better than crystalloid infusion. The hypotension can be corrected by Ephedrine and Phenylephrine, but the fetal academia may be aggravated by Ephedrine. Therefore, the Phenylephrine is recommended if the parturient heart rate is not very slow.Thrombopenia is a common complication on pregnant, the total incidence of thrombopenia is nearly 7.6%. In fact, no matter what kind of thrombopenia, the parturient is in hypercoagulabale state. The epidural anesthesia had been done successfully for the parturient by many scholars. They think the requirement of platelet count can be not strict on epidural anesthesia. The neuraxial anesthesia should be abandoned on the condition that platelet count is less than 50×109/L, the only choice is general anesthesia. The local blocking can also be selected by the anesthesiology department which is not very skillful. The application of Continuous Spinal Anesthesia (CSA) on Gynecology & Obstetric anesthesia and analgesia would be exciting. The labor analgesia of latent stage is a hotspot. The view of labor analgesia can be done on latent stage is supported by many Chinese and foreign academics. The intravenous analgesia is a good complement method of labor analgesia. There is a big difference on the rate of using obstetrics apparatus between China and foreign countries. The reason need to be explored. Continuous Spinal Anesthesia provides a new idea for labor analgesia.