Analgesia for labor

Onset of labor epidural analgesia with ropivacaine and a varying dose of fentanyl: a randomized controlled trial

BACKGROUND

This study was conducted to investigate the onset of labor epidural analgesia using 0.17% ropivacaine with a varying dose of fentanyl. We hypothesized that the onset of analgesia would be shortened in proportion to an increase in fentanyl dose.

METHODS

Women requesting labor epidural analgesia were enrolled in this randomized controlled clinical trial. Each woman was randomly assigned to receive fentanyl 0, 50, 75, or 100 μg with 0.17% ropivacaine 12 mL. The onset and duration of analgesia, the incidence of side effects and patient satisfaction were measured.

RESULTS

Data from 102 women were analyzed. The onset of analgesia (mean ± SD) was shortened with an increasing dose of fentanyl (14.3 ± 5.4, 14.2 ± 6.5, 12.1 ± 5.1, and 8.7 ± 3.8 min with fentanyl 0, 50, 75, or 100 μg, respectively, P=0.001). The duration of analgesia was prolonged with an increasing dose of fentanyl (87.4 ± 20.8, 112.3 ± 19.5, 140.8 ± 18.8, and 143.6 ± 18.6 min with fentanyl 0, 50, 75, or 100 μg, respectively, P<0.001). The incidence of pruritus increased with an increasing dose of fentanyl (P=0.027) but there were no differences for other maternal side effects. There was a significant difference in satisfaction score among groups (P=0.009).

CONCLUSION

The addition of increasing doses of fentanyl to 0.17% ropivacaine contributed to shortened onset as well as prolonged duration of labor epidural analgesia and improved patient satisfaction.

Intensity of Labor Pain and Cesarean Delivery

Some authors have suggested that the intensity of labor pain may be related to labor dystocia. We performed a secondary analysis of a previously published randomized investigation of the effects of epidural analgesia during labor compared with patient-controlled IV meperidine on cesarean delivery. Two-hundred-fifty-nine women who received patient-controlled IV meperidine were identified for analysis. All women were in spontaneous labor with a singleton, term gestation. Women requiring 50 mg or more of meperidine per hour during labor were compared with those who required <50 mg/h. In addition, their pain scores (visual analog scale) were compared before and after analgesia administration. Pain scores were significantly higher in women requiring 50 mg/h of meperidine (8.7 vs 8.0, P = 0.05), and their labors tended to be longer (9 vs 5 h, P = 0.09). More cesarean deliveries for obstructed labor were performed in women requiring >50 mg/h of meperidine (14% vs 1.4%, P = 0.001). Neonatal outcomes were similar in the two groups.

The analgesic effect of sufentanil combined with ropivacaine 0.2% for labor analgesia: a comparison of three sufentanil doses

The combination of opioids with local anesthetics is commonly used for epidural labor analgesia. We examined whether increasing sufentanil in doses of 5, 10, and 15 microg prolonged the duration of labor analgesia produced by ropivacaine. One hundred healthy parturients in the first stage of labor who requested epidural analgesia were enrolled. Parturients were randomized to receive 12 mL ropivacaine 0.2% alone or with sufentanil 5 microg, sufentanil 10 microg, or sufentanil 15 microg. The duration of analgesia, pain score, degree of motor blockade (using a four-point Bromage scale), heart rate, blood pressure, respiratory rate, oxygen saturation, and incidence of nausea and pruritus were recorded. The mean duration of epidural analgesia was 96 +/- 32 min for patients without sufentanil, 134 +/- 27 min for Group 5 (p < 0.01 versus control), 135 +/- 33 min for Group 10 (p < 0.01 versus control), 130 +/- 33 min for Group 15 (p < 0.01 versus control) without differences among sufentanil groups. Between 30 and 90 min, the sufentanil groups (5 microg, 10 microg, and 15 microg) had lower pain scores than the control group (p < 0.01 versus control) but there were no differences among the sufentanil groups. No patient in any group had a Bromage score more than 1. No significant difference was found for opioid-related side effects. We conclude that 5-10 or 15 microg sufentanil induced a similar prolongation of analgesia when combined with ropivacaine 0.2% for initiation of labor analgesia.

IMPLICATIONS

We studied the effect of adding one of three possible sufentanil doses to epidural ropivacaine 0.2% for labor analgesia. Adding sufentanil increased the duration of analgesia but there was no advantage in adding more than 5 microg of sufentanil.