Epidural analgesia with local anesthetics such as ropivacaine was considered as an effective way to relieve the pain of uterine contraction [1,2,3]. However, some studies [4, 5] have shown that a relatively high total dosage of local anesthetic may have an effect on uterine activity by decreasing the rate and strength of the uterine contraction.
Moreover, local anesthetics were more likely associated with epidural-related maternal fever via a number of ways of immunomodulation [6, 7] and cell injury [8]. Thus, epidural administered local anesthetic might potentially cause complications on both maternal and neonatal outcomes time-dependently and dose-dependently. Epidural opioids was also recommended and commonly used in combination with local anesthetics to reduce the dose of local anesthetics and to provide equal, if not superior analgesic effect [9]. Wang et al. reported that ropivacaine with sufentanil for labor analgesia provided effective analgesic effect without significant side effects and delay of the labor progress [10]. But in a recent meta-analysis [11], sufentanil in combination with bupivacaine was considered to be associated with worse neonates Apgar score.
In our institution, as a regular protocol, epidural labor analgesia is conducted using either 0.167 % ropivacaine or 0.1 % ropivacaine in addition to 0.5 µg/ml sufentanil. Although both of them provided almost the equivalent analgesic effects, whether the combination epidural sufentanil and low-concentration ropivacaine will affect the labor progress as well as maternal and neonatal outcomes, as the single usage of high-dose local anesthetic, still remained controversial.
Therefore, we performed a retrospective cohort study to observe women who received 0.167 % ropivacaine alone vs. sufentanil with 0.1 % ropivacaine for epidural labor analgesia to assess the impact of the combination of sufentanil and ropivacaine on both maternal and neonatal outcomes.
Methods
This retrospective group study was approved by the institutional review board from the Obstetrics and Gynecology Hospital of Fudan University and was registered at the Clinical Research Information Service (ChiCTR2100045162, Principal investigator: Yue Li). Informed consent of information collection for research was obtained from all participants. All the study methods were carried out in accordance with the combination of our institutional regulations and guildlines. The study adheres to the ethical standards of the Declaration of Helsinki (1964) and its subsequent amendments.
Medical records were retrospectively reviewed from May 2018 to June 2020, singleton full-term pregnancy women who received epidural labor analgesia via vaginal delivery were included in the study. Women with severe systemic disease that results in functional impairment (American Standards Association, ASA ≥ III) or fetal dysplasia were excluded from the cohort. Parturients were classified into two groups: women who received 0.167 % ropivacaine alone (the R group) and women who received sufentanil with 0.1 % ropivacaine (the SR group) according to different medication regimens for epidural labor analgesia by provider preference. Both regimens were administered via an epidural analgesia pump in a patient-controlled analgesia manner, 8 ml/h epidural analgesic with 0.167 % ropivacaine or 0.1 % ropivacaine in combination with 0.5ug/ml were administered in the R group or the SR group, respectively. The patient-controlled bolus was set to deliver a dosage of 8 ml of analgesics with a lockout interval of 15 min.
Demographic characteristics were collected, including the maternal age, gestational weeks, parity in the gravidae, body mass index (BMI), whether the mother underwent induced labor, presence of pregnancy comorbidities, and neonatal birth weight.
The primary outcome of the present study was the duration of labor progress. The duration of labor progress collected in our study included three stages. The first stage of labor was defined as time from diagnosis of labor to full dilatation of the cervix. The second stage of labor was defined as time from full dilatation of cervix to delivery of the fetus and the third stage of labor was time from delivery of the fetus to delivery of the placenta. The secondary outcome included the incidence of maternal fever, postpartum hemorrhage, fetal distress, episiotomy, instrumental delivery, caesarean section, grade III meconium-stained amniotic fluid (MSAF) and neonatal outcome (Apgar scores < 7, at 1 and 5 min, respectively). Maternal fever was defined as the body temperature > 38℃. Postpartum hemorrhage was defined as estimated blood loss ≥ 500 ml after delivery of the placenta. Fetal distress was diagnosed by the obstetricians and their Apgar scores were assessed by neonatologists after vaginal deliveries and cesarean deliveries. All these demographic information and obstetric outcomes were collected from the electronic medical record system of our hospital.
Statistical analysis
Statistical analysis was performed using SPSS 20.0 (SPSS, Inc., Chicago, IL, USA) and GraphPad Prism 5.01 software (GraphPad Inc., CA, USA). The duration of three stages of labor were presented as mean ± standard deviation (SD). Neonatal outcomes, incidences of maternal fever, postpartum hemorrhage, instrumental delivery, conversion to caesarean section, postpartum hemorrhage the use of episiotomy and the presence of grade III MSAF were presented as percentage. Continuous variables were analyzed using t test, and categorical variables were analyzed using Chi-Square test. Statistical significance was set at P < 0.05.
