Motor block during epidural infusions for nulliparous women in labour: a randomized double-blind study of plain bupivacaine and low dose bupivacaine with fentanyl

A Systematic Review and Meta-Analysis of Randomized Controlled Trials of Labor Epidural Analgesia Using Moderately High Concentrations of Plain Local Anesthetics versus Low Concentrations of Local Anesthetics with Opioids

Purpose

Compared to low concentrations of local anesthetics with opioids for labor epidural analgesia, very high concentrations of local anesthetics are associated with an increased risk of assisted vaginal delivery. We aimed to investigate if moderately high concentrations of plain local anesthetics are also associated with this risk.

Methods

We searched for published randomized controlled trials that compared moderately high concentrations of plain local anesthetics (>0.1% but ≤0.125% bupivacaine, >0.1% but ≤0.125% levobupivacaine, or >0.17% but ≤0.2% ropivacaine) to low concentrations of local anesthetics (≤0.1% bupivacaine, ≤0.1% levobupivacaine, or ≤0.17% ropivacaine) with opioids for labor analgesia. Meta-analyses were performed to compare the risk of assisted vaginal delivery and other perinatal outcomes between these two groups.

Results

We identified nine randomized controlled trials with a total of 1334 participants. Meta-analysis of these nine trials showed no differences in the risks of assisted vaginal delivery (odds ratio [OR] = 1.18; 95% confidence interval [CI], 0.93–1.49) or Cesarean delivery (OR = 0.96; 95% CI, 0.71–1.29) between the two groups. The incidence of motor block was higher in the group of moderately high concentrations (OR = 4.05; 95% CI, 2.19–7.48), while the incidence of pruritus was lower (OR = 0.07; 95% CI, 0.03–0.16).

Conclusion

This systematic review and meta-analysis suggests that the current evidence is inadequate to support that moderately high concentrations of plain local anesthetics increase the risk of assisted vaginal delivery compared to low concentrations of local anesthetics with opioids.

Parturient Controlled Epidural Analgesia with and without Basal Infusion of Ropivacaine and Fentanyl: A Randomized Trial

Introduction:

Parturient controlled epidural analgesia (PCEA) is an established method of providing safe and effective labor analgesia.

Objective:

The aim of this single-blind, randomized controlled trial was to compare the efficacy of PCEA with or without basal infusion (BI) of ropivacaine and fentanyl for the effective management of labor pain associated with normal vaginal delivery.

Materials and Methods:

A total of 78 nulliparous parturients with vertex presentation at term and with cervical dilatation of 3–5 cm demanding for epidural analgesia (EA) were enrolled in the study. EA was initiated and maintained with ropivacaine 0.125% and fentanyl 2 μg/mL. Following an initial epidural loading volume of 8–10 mL, parturients were randomly allocated in two groups of 39 each. PCEA group received bolus of 5 mL at 200 mL/h with lockout interval of 15 min and with maximum volume of local anaesthetic was 20 mL/h and PCEA + BI group – receiving added BI rate of 5 mL/h along with same programmed parameters of PCEA pump.

Results:

No statistically significant difference was observed between the groups in terms of demographic characteristics, duration of labor, delivery methods, maternal satisfaction as well as Apgar score. Mean demand bolus in group PCEA + BI was 0.39 ± 0.59, whereas in group PCEA was 3.31 ± 0.77 (P < 0.05). Mean volume of drug used in group PCEA + BI was 25.57 ± 2.75 mL, while in group PCEA was 22.42 ± 4.56 mL (P = 0.0005). In PCEA + BI group, Visual Analog Scale (VAS) score was 0.07 ± 0.35 at 60 min and 0.06 ± 0.33 at 120 min, whereas in PCEA group, VAS was 0.32 ± 0.62 at 60 min and 0.26 ± 0.50 at 120 min (P = 0.05), respectively.

Conclusion:

BI when added to PCEA, it significantly reduces breakthrough labor pain and demand boluses without prolonging labor duration but at the cost of increased requirement of drug volume when compared to PCEA only group.

Does the use of low dose bupivacaine/opioid epidural infusion increase the normal delivery rate?

To investigate whether using low dose epidural infusion improves the normal delivery rate, outcome of labour was studied in women with singleton vertex presentations randomised to receive either 0.0625% bupivacaine opioid, or plain bupivacaine 0.125% for labour. The infusion rate was titrated to maintain analgesia and a sensory level to T10. Data were analysed using the unpaired t test, Mann-Whitney U test and for categorical variables chi2 test. Adjusted odds ratios for factors significantly associated with non-normal delivery were calculated using stepwise logistic regression. There were 291 women in the low dose and 296 in the plain bupivacaine group. There were no significant differences between groups in parity, race, induction of labour, use of augmentation, cervical dilatation at epidural insertion, duration of any stage of labour or duration or volume of infusion. Total dose of bupivacaine (126 +/- 47 mg versus 91 +/- 32 mg) and the proportion of women with motor block at the end of labour (45% versus 27%) were significantly greater in the plain bupivacaine than in the low dose group (P < 0.0001). The adjusted odds ratios (95% CI) for factors significantly associated with non-normal delivery were primiparity: 4.68 (2.78-7.88), older maternal age: 1.1 (1.05-1.14), longer active second stage of labour: 1.01 (1.005-1.017), total bupivacaine dose: 1.01 (1.005-1.016) and greater cervical dilatation at epidural insertion 1.22 (1.08-1.37). Treatment group and motor block at the end of labour had no significant effect. We found no increase in normal delivery rate with low dose infusions.

Continuous epidural analgesia with bupivacaine 0.125% or bupivacaine 0.0625% plus sufentanil 0.25 μg·mL−1: a study in singleton breech presentation

Epidural analgesia is the most efficient technique for labor pain relief. However, its resultant motor block might impair the mode of delivery, particularly in breech presentation where the risk of dystocia is high. In this trial, we compared bupivacaine 0.125% with a combination of a low concentration of bupivacaine (0.0625%) and sufentanil (0.25 microg.mL(-1)) both administered by continuous infusion. Analgesia, maternal and fetal/neonatal side effects and obstetric outcome were compared between group bupivacaine (n = 23) and group bupivacaine-sufentanil (n = 35). A greater number of patients in the bupivacaine 0.125% group required more than two top-ups (32 vs. 8% of patients, P = 0.03) while pain scores were similar. Motor block at delivery was more pronounced in the bupivacaine 0.125% group. Nausea and pruritus were more often encountered in the bupivacaine-sufentanil group. There was a trend toward a decreased rate of assisted or operative delivery in the bupivacaine-sufentanil group (92% vs. 74%, P = 0.09). Fetal/neonatal data did not differ between groups. Epidural analgesia with bupivacaine-sufentanil required fewer additional top-ups and produced less motor block than did bupivacaine 0.125%. However, there was no significant difference in mode of delivery between the two analgesic regimens.

Minimum local analgesic dose of plain ropivacaine vs. ropivacaine combined with sufentanil during epidural analgesia for labour

We have used the up-and-down allocation technique to assess the relative analgesic potencies of epidural ropivacaine alone and ropivacaine combined with sufentanil 0.75 microg.ml-1 in 42 women requesting epidural analgesia in the first stage of labour. Parturients were randomly allocated to one of the two epidural solutions in a double-blind manner. The concentration of local anaesthetic was determined by the response of the previous parturient: an effective concentration (pain < or = 10 mm on a 10-cm visual analogue pain score within 30 min) resulted in a 0.01% decrease in the concentration of ropivacaine for the next parturient, an ineffective concentration resulted in a 0.01% increase. Minimum local analgesic concentration of ropivacaine alone was 0.13% (95% CI 0.12-0.13%) compared with 0.09% (95% CI 0.08-0.1%) for ropivacaine with sufentanil (p < 0.00001).

Effect of maternal ambulation on labour with low-dose combined spinal-epidural analgesia

Two hundred and twenty-nine nulliparous women who requested regional analgesia during labour were given a combined spinal-epidural block. They were randomly allocated to stay in bed or spend at least 20 min of every hour out of bed. There was no significant difference in duration of labour, analgesia requirements, mode of delivery or condition of the baby between the groups. Ambulation appeared to be safe for the mother and baby. Maternal satisfaction with the low-dose combined spinal-epidural was high in both groups.

Maternal satisfaction with labour analgesia

Satisfaction with childbirth is a multidimensional issue, of which analgesia is but one component. The importance of analgesia as a contribution to overall satisfaction has been recognized increasingly in the last 50 years, but improvement in quality of available analgesia has not always resulted in commensurate improvement in satisfaction. Satisfaction by its very nature has proved to be difficult both to define and to quantify, and no reliable standards of measurement have been accepted. Pain relief in childbirth is subject to many social and cultural modifiers, which continue to change. Control of pain rather than absolute amelioration is seen by many to provide greater satisfaction. Analgesia issues still do not figure prominently in the overall satisfaction of the birthing process for the vast majority of women, despite the availability of and demand for improved methods of relief. The interpersonal relationships established between patient and healthcare providers may ultimately be of more importance in the determination of satisfaction with management.

Risk factors of inadequate pain relief during epidural analgesia for labour and delivery

PURPOSE

To determine the causes of failure of epidural analgesia during labour and delivery.

METHODS

During six months, pregnant patients receiving epidural analgesia and delivering vaginally were studied prospectively. Bupivacaine 0.125% was used for the initial bolus dose and subsequent continuous infusion. Top-ups of the same solution were used for inadequate pain relief assessed using a visual analogue pain score (VAPS) and/or by clinical examination. Inadequate pain relief was defined as the need for > or = 2 top-ups in addition to epidural infusion and failure during delivery as VAPS > or = 30 mm during the expulsion phase.

RESULTS

1009 patients delivered during this period, 596 had epidural analgesia for vaginal delivery of a live infant and data were complete in 456. Inadequate pain relief during labour and during delivery were found in 5.3% and 19.7% of patients. Risk factors of inadequate pain relief included: inadequate analgesic efficacy of the first dose (Odds ratio: 3.5, P = 0.001) and posterior presentation (Odds ratio: 5.6, P = 0.001). Radicular pain during epidural placement was associated with failure during labour (Odds ratio: 3.9, P = 0.05). Duration of epidural analgesia > six hours (Odds ratio: 9.1, P = 0.001) was a risk factor for insufficient pain relief during labour whereas duration of epidural analgesia < one hour was associated with pain during delivery (Odds ratio: 18.3, P = 0.001).

CONCLUSION

Several obstetrical and epidural-related factors increase the risk of inadequate epidural analgesia. For some, simple changes of practice pattern may lead to improved pain relief.

Dorsal column function after epidural and spinal blockade: implications for the safety of walking following low-dose regional analgesia for labour

Walking after regional blockade for labour using low-dose combinations of bupivacaine and fentanyl is possible due to the maintenance of lower limb motor power. In order to investigate concerns that dorsal column function, important in maintaining balance, is impaired after such techniques, clinical assessment of lower limb proprioception and vibration sense was evaluated in parturients after either low-dose epidural (n = 30) or spinal blockade (n = 30) for labour analgesia and compared with spinal anaesthesia (n = 30) for elective Caesarean section using a larger total dose of local anaesthetic. Of the patients receiving low-dose regional labour analgesia 7% (n = 4) had abnormal dorsal column function compared with 97% (n = 29) receiving spinal anaesthesia for Caesarean section (p < 0.001). All patients in the Caesarean section group developed lower limb motor weakness, compared with only 10% (n = 6) in the low-dose groups (p < 0.001). There were no significant differences between the low-dose groups with respect to sensory block, motor block or dorsal column function. Overall, 90% of patients receiving low-dose bupivacaine/fentanyl regional labour analgesia had both normal lower limb motor power and dorsal column function. Assessment of these parameters is recommended before allowing patients to walk after low-dose regional techniques for labour.

Long term backache after childbirth: prospective search for causative factors

OBJECTIVES

To assess in a prospective randomised study the association between motor block resulting from high and low dose epidural infusions of bupivacaine in labour and the incidence of long term backache after childbirth, and to compare the incidence of backache in women not receiving epidural analgesia.

DESIGN

Women requesting epidural analgesia in labour between October 1991 and March 1994 were randomised to receive infusions of either bupivacaine alone or low dose bupivacaine with opioid. Data were collected during labour and the immediate postpartum period from these women and from women recruited at random over the same time from those who had laboured without epidural analgesia. A postal questionnaire about symptoms was sent three months after childbirth to all women. Further data were collected one year after childbirth from those who had reported new backache at three months.

SETTING

St Thomas's Hospital, London.

SUBJECTS

599 women were recruited, of whom 450 (75%) replied to a follow up questionnaire.

RESULTS

152 women (33.8% of responders) reported backache lasting three months after delivery and, of these, 33 (7.3%) had not previously suffered with backache. There were no significant differences between the treatment groups in the incidence of postnatal backache overall or of new backache or any symptoms after childbirth. Among all demographic, obstetric, and epidural variables examined the only factors significantly associated with backache after childbirth were backache before and during pregnancy.

CONCLUSIONS

The incidence of new long term backache was not significantly increased in women who received epidural analgesia in labour. Motor block resulting from epidural local anaesthetic administration was not a significant factor in the development of backache.

Epidural infusion of low-dose bupivacaine and opioid in labour. Does reducing motor block increase the spontaneous delivery rate?

Labouring women were randomly allocated to receive epidural infusions during labour of either 0.125% plain bupivacaine (n = 200) or a combination of 0.0625% bupivacaine with either 2.5 micrograms.ml-1 fentanyl or 0.25 micrograms.ml-1 sufentanil (n = 199) each starting at 12 ml.h-1 and adjusted as necessary to maintain analgesia. The dose of bupivacaine, both hourly (p < 0.001) and total (p < 0.001), was significantly lower in the group receiving the combination. Motor block was significantly less common and less severe in the combination group (p < 0.001). These reductions did not result in a significant increase in spontaneous deliveries. Maternal satisfaction with first (p < 0.001) and second stage analgesia (p < 0.001) was significantly increased in the combination group. The addition of opioid to the epidural infusion did not reduce the incidence of perineal pain. There were no significant differences between the groups in neonatal outcome or the incidence of early postnatal symptoms.