Intradural block is currently the most effective form of labor analgesia, and both the American College of Obstetricians and Gynecologists and the Society of Anesthesiologists have endorsed it as the preferred form of labor analgesia. Numerous studies have shown that it does not increase the rate of cesarean delivery, but may prolong the second stage of labor and increase the rate of assisted instrumental delivery. It is the most recommended form of analgesia due to good analgesia and blocked maternal sympathetic activity, good blood perfusion to the uterus, better maintenance of placental substance exchange, improved acid-base balance of the fetus and newborn, and high maternal satisfaction. Even in women with severe hyperemesis and preeclampsia, epidural blockade still provides safe and effective analgesia for spontaneous delivery, thus reducing the rate of cesarean delivery. Optimization of patient-controlled epidural analgesia (PCEA) delivery mode Currently, most of the intradural block analgesia uses patient-controlled epidural analgesia (PCEA) with low concentration of local anesthetics combined with analgesics, which is more individualized and reduces the dosage of drugs compared with continuous infusion mode. Boselli et al. concluded that combined background continuous infusion of PCEA significantly increases anesthetic consumption compared to PCEA without background infusion, but does not further improve analgesia and maternal satisfaction, but may prolong labor. More studies have concluded that combined background infusion PCEA does not significantly increase anesthetic consumption and has a more satisfactory analgesic effect, thus it may be the most used modality at present. The reasons for the inconsistent results of the studies may be related to the differences in study methods, drugs used, doses, etc. Debon et al. concluded that the duration of epidural analgesia has a certain circadian rhythm, with the same dose of drugs producing longer analgesia during the day than at night, thus suggesting that we should take this circadian rhythm into account when studying the analgesic effects of different methods and drugs, so that the groups studied The inconsistency of the aforementioned results may be related to the fact that the analgesic effect of the same dose of the drug was longer during the day than at night. The inconsistency of the aforementioned results may also be related to this. Two recent studies have proposed improvements to the background infusion method, and Lim et al. used a computer-integrated PCEA (CI-PCEA) technique in which the background infusion rate was automatically adjusted according to individual maternal needs. The authors concluded that CI-PCEA did not increase the amount of anesthetic medication compared to PCA without background infusion, but improved maternal satisfaction. Wong et al. concluded that a single injection of the same dose resulted in better diffusion and distribution of anesthetic drugs in the epidural space compared with continuous epidural infusion. They therefore changed the background continuous infusion dose of 12 mL/h (0.062 5% bupivacaine + 2 ug/mL fentanyl) to a single injection of 6 mL every 30 min, called programmed intermittent epidural administration (PIEB). In the event of analgesic deficit on the basis of this background infusion maternal self PCEA compressions were performed, and if analgesia deficit remained, a single infusion of 0.125% bupivacaine was administered by the anesthesiologist for rescue (rescue boluse). Studies have shown that this mode of analgesia is comparable to PCEA with continuous background infusion, but requires fewer rescue attempts, less total drug consumption, and higher patient satisfaction. Combined lumbar anesthesia and epidural block analgesia (CSEA) Traditional epidural analgesia has some shortcomings, such as slower onset of action, relatively more drugs required for analgesia, possible prolongation of the second stage of labor, increased oxytocin dosage and instrumental assistance rate. In order to reduce these adverse effects, CSEA technique has been applied to labor analgesia. Compared to epidural analgesia alone, CSEA has a faster onset of analgesia, higher maternal satisfaction, and much lower dosage of maintenance analgesia, but may have a higher incidence of pruritus, with no significant differences in maternal motility, rate of instrumental and cesarean delivery, incidence of post-dural puncture headache (PDPH), or effects on the newborn Do]. There is no standard epidural or CSEA analgesic technique, and as for subarachnoid (intrathecal) administration, some authors use simple opioid analgesics, most commonly fentanyl and sufentanil, which ensure rapid analgesia without blocking sensory and motor nerves and without disturbing maternal hemodynamics. However, high doses of opioids, especially sufentanil (≥7.5 ug), may However, high doses of opioids, especially sufentanil (≥7.5 ug), may cause uterine hyperexcitability and abnormal fetal heart rate, and therefore require intensive monitoring after administration. To reduce or avoid this side effect and to prolong the duration of analgesia, more authors have used a combination of low-dose local anesthetics (2.5 mg bupivacaine, 2.5 or 3 mg ropivacaine) and low-dose opioids (1.5 ug sufentanil or 25 ug fentanyl) for intrathecal administration. Fentanyl produced satisfactory analgesia when combined with 2.5 mg bupivacaine intrathecally, and higher doses of fentanyl did not prolong the duration of analgesia or further improve analgesic quality. Evaluation of new local anesthetics Epidural bupivacaine provides excellent analgesia in spontaneous labor and various assisted deliveries, and it has been a widely used local anesthetic in obstetric anesthesia, but it has some disadvantages, including cardiac and central neurotoxicity after massive blood entry and blockade of motor nerves at higher concentrations. The newer local anesthetic, ropivacaine, has been used with great enthusiasm for labor analgesia because of its advantages of low cardiotoxicity and more pronounced sensorimotor blockade separation. A pooled analysis in 1998 concluded that those who applied ropivacaine had higher rates of spontaneous delivery, fewer forceps assisted deliveries, lower incidence of maternal motor nerve block, and better neurobehavioral scores in newborns compared to bupivacaine. In earlier studies, local anesthetic concentrations (0.2% to 0.25%) were much higher than the current routinely used analgesic concentrations (0.062 5% to 0.125%), and studies on the minimum local analgesic concentration (MLAC) found that the efficacy of ropivacaine was about 40% lower than that of bupivacaine, so Polley et al. concluded that the analgesic effectiveness and side effects of the two drugs must be compared on the basis of equivalent doses to be meaningful. In 2003, Halpern et al. pooled 23 randomized controlled studies and concluded that there was no difference between ropivacaine and bupivacaine in terms of quality of analgesia and maternal satisfaction with analgesia, nor was there a significant difference in spontaneous delivery rates and other obstetric regressions, nor in neonatal regressions. This study still included some earlier trials with higher concentrations of local anesthetics, so there was no comparison of the differences between the two drugs for motor nerve blockade. These findings have prompted questions about the advantages of the newer drug for labor analgesia. Bolukbasi chose 40 women to compare continuous epidural infusion of 0.062 5% ropivacaine + 2ug/mL fentanyl with 0.062 5% bupivacaine + 2ug/mL fentanyl for labor analgesia and found no significant differences in analgesia, degree of sensorimotor blockade, labor and delivery and neonatal assessment. There were no significant differences in analgesia, sensorimotor block, labor and delivery mode, or neonatal assessment. Another multicenter study comparing 0.125% bupivacaine + 0.75ug/mL sufentanil with 0.125% ropivacaine + 0.75ug/mL sufentanil using PCEA with no background infusion in 450 women showed no significant differences in analgesic efficacy, local anesthetic consumption, degree of motor block, or mode of delivery between the two groups. This seems to suggest that at the low concentrations currently used, there is no advantage to be gained from ropivacaine and that perhaps optimizing the mode of administration is more important. As for the levorotatory isomer of bupivacaine, levobupivacaine, studies on the minimum analgesic dose for intrathecal administration have shown that it is about I.25 times more effective than ropivacaine and 0.81 times more effective than bupivacaine, but at the commonly used analgesic doses, levobupivacaine has no more advantage over bupivacaine and ropivacaine, both in terms of analgesic effect and adverse effects. The effect of walkable analgesia on labor Currently, whether epidural analgesia or CSEA, since low concentrations of local anesthetics and small doses of opioid analgesics are used, there is minimal or no blockade of the motor nerves, so as long as the membranes have not yet been broken, the woman can be encouraged to move out of bed appropriately, which is also called walkable analgesia. It is generally believed that this can increase the strength of uterine contractions, avoid pressure on the inferior vena cava, facilitate the descent of the fetal head, and relax the pelvic floor muscles, all of which are conducive to shortening labor and facilitating delivery. Frenea et al. concluded that walking had no effect on the duration of labor, but reduced the use of local anesthetics and oxytocin. In contrast, Karraz’s study of 221 women concluded the opposite, that walking shortened labor but had no effect on the amount of local anesthetics or oxytocin used. Davies et al. concluded that maternal equilibrium is already compromised at the time of delivery, and that although this effect is not exacerbated by the initial intrathecal administration of small amounts of local anesthetics and analgesics in CSEA, the subsequent epidural analgesia may further compromise maternal equilibrium. Therefore, we should be cautious when encouraging women to get out of bed. Motor ability should be assessed before getting out of bed, and the woman should be accompanied when walking. The timing of analgesia onset and termination is generally considered to be appropriate after the opening of the uterus to 3 cm, when labor is in an active phase. However, in a recent randomized controlled study by Ohel et al. on 449 primigravida, 221 cases had an opening of less than 3 cm (mean 2.4 cm) and 228 cases delayed epidural analgesia until the opening of 4 cm (mean 4.6 cm) at the request of the mother. The epidural analgesia at the early stage of labor shortened the first stage of labor and increased maternal satisfaction with the analgesia, thus making it more acceptable to women. This is also consistent with the findings of Wong et al. As for the timing of epidural analgesia cessation, most of them terminate epidural administration when the uterus is fully opened, which is thought to improve maternal effort in the second stage of labor and reduce the rate of instrumental delivery. However, a recent pooled analysis including 5 randomized controlled studies showed that there is no evidence that discontinuing epidural analgesia when the uterus is fully opened reduces the rate of instrumental deliveries or has an impact on maternal outcome compared with discontinuing analgesia until delivery, with the only difference being that those who continued analgesia until delivery were more satisfied with analgesia in the second stage of labor. The authors therefore recommend that a larger study be conducted to determine a more appropriate timing for termination of epidural analgesia. In addition to the aforementioned prolongation of the second stage of labor, increased rates of instrumental delivery, and the potential for pruritus and slowed fetal heart rate associated with higher doses of opioid analgesics, fever, post-dural puncture headache (PDPH), and effects on breastfeeding have received attention in recent years. The reasons for the increased body temperature in women undergoing epidural analgesia are unclear and may be related to changes in the balance between heat production and heat loss in the thermoregulatory center and vascular regulation. During normal labor, heat production is high due to uterine contractions, pain, and increased skeletal muscle movement, and heat is dissipated through sweating and hyperventilation. The vasodilatation of the blocked area after epidural labor analgesia, along with the reduction in skeletal muscle movement, contributes to a decrease in body temperature. However, analgesia reduces pain-induced sweating and hyperventilation, reducing evaporative heat loss due to hyperventilation, while compensatory vasoconstriction above the plane of the block reduces heat loss, resulting in an increase in maternal body temperature. This increase in body temperature rarely produces significant fever and is unlikely to have a detrimental effect on the fetus. Of course, if hyperthermia occurs, the basal metabolic rate rises and acidic metabolites increase, easily causing acid-base imbalance and electrolyte disturbance in body fluids, resulting in the accumulation of acid in the internal environment where the fetus is located, and if labor is stalled at this time, it is easy to cause intrauterine distress and early cesarean delivery is recommended. Regarding the management of accidental dural puncture during epidural puncture, in 2005, Baraz et al. surveyed all anesthesia departments in the United Kingdom where labor analgesia was performed. 28% of hospitals routinely placed the epidural catheter directly into the subarachnoid space after accidental dural puncture, 41% routinely reperfused the catheter, and the remaining 31% of units could handle both, whereas in a 1993 survey 99% of the units were routinely re-punctured. The apparent increase in direct placement into the subarachnoid space can be explained by the rapid analgesic effect produced by intrathecal administration, the avoidance of further dural puncture, and the inflammatory response around the catheter that may contribute to a reduction in the incidence and severity of PDPH. In subsequent deliveries, the second stage of labor was limited in 29% of units, and delivery was accomplished with the help of suction or forceps to avoid maternal forceful breath-holding. It is commonly believed that breath-holding can significantly increase intra-abdominal and intracranial pressure, causing more cerebrospinal fluid leakage and worsening PDPH. yet 69% of units did not perform any interventions in the second stage of labor, which they believed were not effective in reducing the incidence of PDPH. Blood patching remains the accepted and most effective method of managing PDPH. Little attention has previously been paid to the effects of labor analgesia on breastfeeding, and interest has recently been aroused by the study of Beilin et al. They randomized 180 transwomen who had previously breastfed their children and still wanted to breastfeed after the current delivery into 3 groups for epidural labor analgesia according to the dose of epidural-combined fentanyl: 1 group without fentanyl, 1 group with a small dose of fentanyl (1 to 150ug), and There was also 1 group compounded with high dose of fentanyl (>150ug). The results showed that the group with high-dose fentanyl had the lowest neurobehavioral scores on day 1 and the highest incidence of breastfeeding difficulties during the first 6 weeks after delivery (2%, 5%, and 17% in the three groups, respectively). Of course, many factors influence breastfeeding and further studies are needed to confirm the reliability of such results, but at least it reminds us to avoid using high doses of fentanyl during labor analgesia.