Fetal effects of combined spinal-epidural vs epidural labour analgesia: a prospective, randomised double-blind study

To estimate the effects of combined spinal-epidural and traditional epidural analgesia on uterine basal tone and its association with the occurrence of fetal heart rate (FHR) abnormalities. Seventy-seven laboring patients who requested pain relief during labor were randomly assigned to combined spinal-epidural (n=41) or epidural analgesia (n=36). Uterine contractions and FHR were recorded 15 minutes before and after analgesia. Uterine tone was evaluated with intrauterine pressure catheter. Primary outcomes were the elevation of baseline uterine tone and occurrence of FHR prolonged decelerations or bradycardia after analgesia. The influence of other variables such as oxytocin use, hypotension, and speed of pain relief were estimated using a logistic regression model. The incidence of all outcomes was significantly greater in the combined spinal-epidural group compared with epidural: uterine hypertonus (17 compared with 6; P=.018), FHR abnormalities (13 compared with 2; P<.01), and both events simultaneously (11 compared with 1; P<.01). Logistic regression analysis showed the type of analgesia as the only independent predictor of uterine hypertonus (odds ratio 3.526, 95% confidence interval 1.21-10.36; P=.022). For the occurrence of FHR abnormalities, elevation of uterine tone was the independent predictor (odds ratio 18.624, 95% confidence interval 4.46-77.72; P<.001). Regression analysis also found a correlation between decrease on pain scores immediately after analgesia and the estimated probability of occurrence of hypertonus and FHR abnormalities. Combined spinal-epidural analgesia is associated with a significantly greater incidence of FHR abnormalities related to uterine hypertonus compared with epidural analgesia. The faster the pain relief after analgesia, the higher the probability of uterine hypertonus and FHR changes. Umin Clinical Trials Registry, http://www.umin.ac.jp/ctr/index.htm, UMIN000001186 I.

Combined spinal epidural analgesia (CSE) for labor pain relief has become increasingly popular. However, the effect of intrathecal sufentanil on the incidence of uterine hyperactivity and fetal heart rate (FHR) abnormalities remains controversial. We hypothesized that the use of intrathecal sufentanil in a dose of 7.5 microg is more likely to induce a nonreassuring FHR tracing than a small dose of spinal sufentanil combined with bupivacaine or epidural analgesia. Three-hundred parturients were randomized into three groups. In the first group, epidural analgesia was initiated with 12.5 mg of bupivacaine, 12.5 microg of epinephrine, and 7.5 microg of sufentanil in a volume of 10 mL (EPD group). In Group 2, initial intrathecal analgesia consisted of 2.5 mg of bupivacaine, 2.5 microg of epinephrine, and 1.5 microg of sufentanil (BSE group); in Group 3, spinal analgesia consisted of 7.5 microg of sufentanil (SUF group). Analgesia was maintained in all groups with patient-controlled epidural analgesia using bupivacaine 0.125%, 1.25 microg/mL of epinephrine, and 0.75 microg/mL of sufentanil (bolus, 4 mL; lockout, 15 min). Cardiotocography was monitored continuously 15 min before analgesia and for 60 min after the start of analgesia. The quality of analgesia, labor, and neonatal outcome and side effects were recorded. Twenty-four percent of patients in the SUF group developed FHR abnormalities (bradycardia or late decelerations) during the first hour after initiation of analgesia compared with 12% in the BSE group and 11% in the EPD group. Uterine hyperactivity occurred in 12% of parturients in the SUF group but in only 2% in the other groups. Onset of analgesia was more rapid in both CSE groups as compared with the EPD group. However, 29% of patients in the BSE group developed severe hypotension, requiring IV ephedrine (29% in the BSE group versus 7% and 12% in the EPD and SUF groups, respectively). All these differences reached statistical significance. The present data corroborate previous recommendations of caution when performing CSE using a large dose (7.5 microg or more) of spinal sufentanil because of the risk of uterine hyperactivity and FHR abnormalities. Combined spinal epidural analgesia (CSE) produces pain relief during labor. Fetal heart rate changes after CSE using intrathecal sufentanil have been reported. We performed a randomized, blinded trial confirming that fetal heart rate changes are more frequent after CSE using 7.5 micro g of intrathecal sufentanil as compared with other forms of neuraxial labor analgesia.

Among nulliparous women, there appears to be an association between the use of epidural analgesia during labor and an increased risk of dystocia. We tested the hypothesis that combined spinal-epidural analgesia, which permits ambulation during labor, is associated with a lower incidence of dystocia than continuous lumbar epidural analgesia.