Delivery analgesic drug Ropivacaine, a new local anesthetic drug, has become the analgesic drug of choice for the intravesical block delivery analgesia technique in China because of its distinctive sensory-motor blocking dissociative properties. Among the papers on pharmacological labor analgesia methods used, ropivacaine was used most frequently, with a total of 16 papers. The results of one of the studies showed that ropivacaine at 0.075% ~ 0.2% was the commonly used concentration for epidural labor analgesia. The EC50 for epidural ropivacaine analgesia was 0.063% and the minimum effective concentration (MLAC) for first stage analgesia was 0.154% as measured by sequential tests in the papers. In order to increase the analgesic effect without increasing the degree of motor block, the combination of ropivacaine and opioid analgesic drugs represented by 1-2 μg/ml fentanyl or 0.3-0.5 μg/ml sufentanil is often used, and epidural patient controlled analgesia (PCA) is used. epidural analgesia (PCEA) as the current common mode of drug delivery in China. However, the higher price of patient-controlled analgesia pump and ropivacaine limits the use in primary hospitals, and it is recommended to use a lower concentration of bupivacaine instead of ropivacaine, which can also achieve a better analgesic effect in labor. Combined spinal epidural analgesia (CSEA) The use of combined spinal epidural analgesia (CSEA) technique accounts for 29.4% of the papers on intradural block analgesia, which indicates that CSEA has become a more common method of obstetric anesthesia and analgesia. Ropivacaine 2-3 mg or bupivacaine 1.25-2.5 mg [3] can be used as a local anesthetic for subarachnoid administration, with the advantages of rapid onset of action, excellent analgesia, and almost no motor block. The disadvantage is that the duration of analgesia is short, only 30-50 min, and the subsequent analgesia during labor depends on intermittent or continuous epidural administration.CSEA labor analgesia is also usually administered intrathecally with fast-acting fat-soluble anesthetic drugs, such as fentanyl 10 μg-25 μg or sufentanil 2.5 μg-10 μg, which can be maintained for about 2-3 hours. Some studies have shown that the appropriate dose of sufentanil for labor analgesia in the country is 5 to 6 mg [4], and the woman can walk during analgesia. The combination of sufentanil 2.5 μg and bupivacaine 2.5 mg produces analgesia rapidly and has a longer duration than sufentanil alone; unfortunately, there are fewer such papers in China. The majority of papers confirm that epidural analgesia or combined lumbar epidural analgesia for labor analgesia is safe and effective and has beneficial effects on the mother and the baby. Some studies have focused on placental-fetal endocrine function and have shown that labor analgesia reduces maternal peripheral blood cortisol hormone, thereby reducing the stress response to labor, and that cortisol concentrations in maternal cord blood and amniotic fluid do not change after analgesia. It was also demonstrated that the secretion of estrogen/progesterone, plasma prostaglandin E2 (PGE2), and IL-1b were not affected by labor analgesia. Other studies have also shown that CSEA labor analgesia increases nitric oxide levels and facilitates maternal hemodynamic stability. Adverse effects of CSEA CSEA is as safe as the general epidural technique, but side effects and complications that may occur in a small number of patients include: pruritus, nausea and vomiting, hypotension, urinary retention, bradycardia, maternal respiratory depression, and postdural puncture headache (PDPH). Subarachnoid use of opioids increases uterine tone and can lead to fetal bradycardia, which may be related to the ability of opioids to reduce maternal catecholamine concentrations. PDPH is the most concerned problem of obstetric anesthesia and analgesia using lumbar anesthesia. maternal PDPH is twice as high. In contrast, the lumbar puncture needle in the combined lumbar and rigid kit is 25G or 27G, which is more refined and has a pencil point design, resulting in a much lower incidence of headache. In more than 20,000 cases of combined lumbar and epidural anesthesia and labor analgesia performed in the Department of Anesthesiology of Peking University First Hospital, except for postoperative headache caused by epidural needle puncturing the dura, the incidence of PDPH with the 25G lumbar puncture needle in the combined lumbar and epidural kit was 0.4%, which was much lower than the 1% reported. Even when headache occurred, the symptoms were mild, required no special management, and resolved on their own. Therefore, it can be presumed that the traditional position of lying down with the pillow after lumbar anesthesia is not associated with the reduction of PDPH under the premise of using the lumbar rigid combination kit for labor analgesia. The actual incidence of sufentanil- and fentanyl-induced central respiratory depression is low and has been reported only occasionally, but should be taken seriously enough in CSEA. This respiratory depression generally appears rapidly, and therefore, any patient receiving CSEA needs to be monitored for respiratory function for more than 20 min after subarachnoid administration of opioids. Effects on maternal uterine contractions, labor progression, and mode of delivery Accurate assessment of the effects of intralesional block analgesia on labor and cesarean delivery rates is difficult because labor analgesia affects only one of the four obstetric factors (psychiatric factors, labor force, birth canal, and fetus) – psychiatric factors – while the other three obstetric factors interact with each other Leighton [5] concluded that epidural labor analgesia had no effect on cesarean rate, instrumental delivery rate, or first stage of labor, but it prolonged the second stage of labor and increased the amount of contractions. One study in a national paper showed that epidural labor analgesia caused a transient decrease in uterine contractility, but was not associated with uterine contraction hormones and had no adverse effect on the overall labor process. Several other obstetric papers with larger samples have shown [6] that labor analgesia with combined epidural or lumbar epidural analgesia can increase the rate of contraction hormone use and lead to prolonged first and second stage of labor and an increase in the rate of assisted instrumental delivery, but can effectively reduce the rate of cesarean delivery without increasing the incidence of postpartum hemorrhage or neonatal asphyxia. In the combined analgesia and epidural groups, the active period after analgesia was prolonged by 84 min and 116 min, and the second stage of labor was prolonged by 13 min and 14 min, respectively, while the main reason for the increased rate of forceps assisted delivery after analgesia was fetal heart abnormalities. This is consistent with the findings of the meta-analysis by Sharma et al [7] that intradural block delivery analgesia increased the amount of indocin, prolonged labor, and increased the rate of assisted labor, but did not increase the rate of cesarean delivery. There is almost no difference in the formulation of analgesic drugs and the timing of analgesia between us and foreign countries in epidural or combined analgesia for labor analgesia, and even the amount of drugs used per unit time is less than foreign countries, so there should be no reason to give up the technique of labor analgesia with intradural block, as long as the newborn has a good outcome, the expected purpose of labor analgesia has been achieved, after all, “fish After all, “fish” and “bear’s paw” cannot be obtained at the same time. However, there are still higher requirements for anesthesiologists and obstetricians, and we are required to make continuous efforts to explore and research in order to minimize the adverse effects of labor analgesia on labor and delivery. Maternal fever and intrauterine infection Only one of the above papers reported 2 cases of high fever during labor in women with epidural labor analgesia, but it has long been found in overseas clinical studies that maternal body temperature often rises above 38°C in women with intravesical block labor analgesia, with an incidence of 19% in primigravida and 1% in transmigravida. The reasons for this are unclear, and it is assumed that the possible causes are prolonged labor in women who have received labor analgesia, which leads to an increased likelihood of intrauterine infection, and a disruption of the balance of the stress endocrine-immune network caused by analgesia, which leads to fever. This requires the obstetrician to closely monitor the labor process and fetal heart rate and to take appropriate measures to address any elevated maternal temperature or suspected intrauterine infection. The timing of analgesia is usually considered to be after the opening of the uterine opening to 3 cm in the active stage before the implementation of intrathecal block analgesia. However, in clinical work, it is found that many women who have had a cesarean section do not have a cesarean section. However, in our clinical work, we found that many women could not persist until the opening of the uterus was 4-5 cm, or even when the uterus was only 1-2 cm open, they already had severe labor pains and strongly requested labor analgesia. If we have to follow the analgesic guidelines, the analgesic time limit is too short, which makes the intra-vertebral block technique of labor analgesia meaningless to some extent. It has been reported in the foreign literature and confirmed that latent analgesia, like active analgesia, does not prolong labor, does not increase the use of contractions, and does not increase the cesarean delivery rate. Therefore, in the 2002 clinical guideline [8], it was corrected to “women should not wait until the uterine orifice is 4-5 cm before starting epidural analgesia.” Happily, individual hospitals in China have started to perform latent analgesia and have similarly concluded not to prolong the first stage of labor. Rifentanil and labor analgesia Although the intradural block method of labor analgesia is recognized as the most effective and commonly used method of labor analgesia, it still has shortcomings, such as it is an invasive operation, there is a potential risk of nerve injury, the mother is not willing to accept this method of analgesia, there are contraindications to intradural block; there is also the possibility of puncture failure, poor position of the epidural catheter or prolapse leading to analgesia failure, and many other reasons. For many reasons, we need to find another method of labor analgesia that is easier, has reliable analgesic effect and can even replace epidural analgesia. Remifentanil is a new type of opioid with strong potency, rapid onset of action, and a time-related half-life (t1/2cs) of 3-5 min, so the effect disappears quickly, no accumulation effect, easy to control by intravenous infusion, and no need to worry about prolonged action time. This drug is used for induction and maintenance of anesthesia in the perioperative period. Like other opioids, remifentanil easily passes through the placenta, and its drug metabolism in the umbilical artery/umbilical vein of the newborn is 30%, and the maternal plasma clearance of remifentanil is 93 ml.min-1.kg-1, which is twice as high as that of non-maternal [9]. Due to the specificity of its pharmacokinetics in obstetrics, it is determined that remifentanil is rapidly metabolized in the mother and fetus, so it does not have the prolonged respiratory depression and sedation of other opioids and has no serious effects on either the mother or the newborn. Several foreign publications reported [10-12] that the technique of intravenous self-administered analgesia with remifentanil was used for maternal labor analgesia, and preliminary studies showed that the analgesic effect of remifentanil was superior to that of nitrous oxide inhalation analgesia and intravenous dulcolax analgesia, and there was no difference in the Apgar score of newborns when maternal remifentanil 0.1 μg/kg/min was administered intravenously compared with fentanyl 100 μg epidurally. However, in the actual clinical application, the safety of remifentanil labor analgesia for mother and baby needs to be further confirmed. During the analgesic process, maternal respiratory indexes (respiratory count, SpO2), degree of sedation and fetal heart rate should be continuously monitored, and remifentanil should be stopped 15 min before fetal delivery. Anesthesiologists should explore and study the setting of patient-controlled intravenous analgesia (PCIA) mode for remifentanil delivery analgesia, which is the key to achieve better analgesic effect and ensure the safety of mother and baby. There are many methods of labor analgesia, and they are divided into two main categories: non-pharmacologic and pharmacologic analgesia. The advantage of non-pharmacological analgesia is that it has minimal effect on labor and mother and baby, but the disadvantage is that the analgesic effect is poor, which is suitable for mild or moderate labor pain, or for latent analgesia in the first stage of labor and can delay the use of pharmacological analgesia; intradural block analgesia is one of the pharmacological analgesia methods, which is recognized as the best analgesic effect in the world (the analgesic efficiency can reach more than 95%) and one of the most popular methods of labor analgesia. It is one of the most popular methods of labor analgesia. It is especially suitable for people with severe labor pain. With the emergence of new techniques of combined lumbar-epidural block (CSEA) and patient-controlled epidural analgesia (PCEA), and the application of new drugs – Sufentanil and Ropivacaine – the “walking epidural analgesia” (WEEA) has been introduced. “However, because it requires the participation of anesthesiologists and has a high technical content, coupled with the interaction of many factors such as the management mode, operation process and old-fashioned philosophy, it has restricted the widespread application of intravesical block for labor analgesia in China. The establishment of a standardized pain management organization [13], specifically for labor analgesia, that is to establish a medical service system for labor analgesia that is suitable for China’s national conditions. The ideal mode of labor analgesia should be that hospitals should provide as many labor analgesic techniques as possible, including various non-pharmacological and pharmacological methods of labor analgesia, and women can choose their own labor analgesic methods according to their knowledge of labor analgesia, their own pain perception, their progress of labor, and their economic affordability, because labor analgesia is the right of women, and the choice of labor analgesic methods is also the right of women. The choice of labor analgesia method is also the right of the mother. Therefore, it is recommended that two or more modes of labor analgesia can be used during labor, with non-pharmacological analgesia (guided delivery or HANS method) being the main method during the latent phase when labor pain is mild, and intravesical block analgesia being the main method when labor pain increases during the active phase. The laughing gas inhalation analgesia method is applicable to all stages of labor and is easier to use, so it is more suitable to be promoted and applied in primary hospitals, but it requires the participation of anesthesiologists and implementation according to the anesthesia routine, and equipped with the necessary resuscitation monitoring equipment to ensure safety.