Objective  To investigate the influence of epidural local anesthetics consumption volume (ELACV) during neuraxial labor analgesia on the effect of epidural anesthesia when undergoing intrapartum cesarean delivery.

  Methods  Parturients undergoing intrapartum cesarean delivery after neuraxial labor analgesia were prospectively recruited in Beijing Obstetrics and Gynecology Hospital, Capital Medical University from May 2019 to February 2020. Using the average amount (60 mL) of ELACV of all the parturients as the cut-off in our study, we divided the parturients into the high volume group (ELACV≥60 mL) and the low volume group (ELACV < 60 mL). Epidural anesthesia was performed by a top-up of the epidural catheter, which was introduced during the labor, with the experimental dose of 1.5% lidocaine 3 mL and a mixture of 10~20 mL of 1% lidocaine and 0.5% ropivacaine. The failure rate and effect of epidural anesthesia were compared between the two groups.

  Results  A total of 36 parturients who met the selection and exclusion criteria were enrolled. There were 17 cases in the high volume group and 19 cases in the low volume group. The failure rate of the high volume group was significantly higher than that of the low volume group (23.5% vs. 0, P=0.040). There was no significant difference in the local anesthetics consumption during cesarean delivery (P=0.057), the length of time from the first epidural top-up dose to skin incision (P=0.290), and the length of time from the first epidural top-up dose to the end of surgery (P=0.748) between the two groups. All surgeries were successfully completed (4 cases, who suffered failure of epidural anesthesia, were converted to combined spinal epidural anesthesia) with neither maternal nor neonatal adverse events. Pearson correlation analysis showed that the level of sensory block at the 10 minutes after the first epidural top-up dose was significantly correlated with the ELACV (r=0.509, P=0.003), but not linearly correlated with the ELACV per hour (r=0.272, P=0.125). In the high volume group, the level of sensory block at the 10 minutes after the first epidural top-up doseT9 (T6, T9) vs. T6 (T4, T7), P=0.048 and the grade of motor block at the end of surgery1(0, 1) vs. 2(1, 3), P=0.034 on the right side of the body were lower than those in the low volume group. The difference of the proportion of parturients who complained of discomfort during muscle separation after skin incision (23.1% vs. 0, P=0.058) and discomfort during abdominal exploration (30.8% vs. 15.8%, P=0.401) was not statistically significant between the high volume group and the low volume group.

  Conclusion  In the parturients, who need intrapartum cesarean delivery after neuraxial analgesia, the larger the volume of local anesthetics consumed during labor analgesia, the greater the chance of failure and poor effect during conversion of epidural analgesia to epidural anesthesia.