A comparison of epidural analgesia with 0.125% ropivacaine with fentanyl versus 0.125% bupivacaine with fentanyl during labor

Effect of Remimazolam Supplementation on Propofol Requirements During Hysteroscopy: A Double-Blind, Dose-Response Study

BACKGROUND

Propofol is commonly used for procedural sedation but may increase side effects in a dose-dependent manner. Remimazolam, an ultrashort-acting benzodiazepine, has been approved for procedural sedation but may delay awakening. This study tested the hypothesis that remimazolam as a supplement reduces effect-site propofol concentration (Ce prop ) required to suppress response to cervical dilation in patients undergoing hysteroscopy.

METHODS

One hundred and fifty patients who were scheduled for hysteroscopy were randomized to receive 0, 0.05, 0.1, 0.15, or 0.2 mg·kg -1 intravenous remimazolam, followed by a bolus of sufentanil 0.15 μg⋅kg -1 , and a target-controlled propofol infusion. The initial target Ce prop was 3.5 μg·mL -1 and was increased or decreased in subsequent patients by steps of 0.5 μg·mL -1 according to whether there was loss of response to cervical dilation in the previous patient. We used up-down sequential analysis to determine values of Ce prop that suppressed response to cervical dilation in 50% of patients (EC 50 ).

RESULTS

The EC 50 of propofol for suppressing response to cervical dilation was lower in patients given 0.1 mg·kg -1 (2.08 [95% confidence interval, CI, 1.88-2.28] μg·mL -1 ), 0.15 mg⋅kg -1 (1.83 [1.56-2.10] μg·mL -1 ), and 0.2 mg⋅kg -1 (1.43 [1.27-1.58] μg·mL -1 ) remimazolam than those given 0 mg⋅kg -1 (3.67 [3.49-3.86] μg·mL -1 ) or 0.05 mg⋅kg -1 (3.47 [3.28-3.67] μg·mL -1 ) remimazolam (all were P < .005). Remimazolam at doses of 0.1, 0.15, and 0.2 mg·kg -1 decreased EC 50 of propofol by 43.3% (95% CI, 41.3%-45.5%), 50.3% (48.0%-52.8%), and 61.2% (58.7%-63.8%), respectively, from baseline (remimazolam 0 mg⋅kg -1 ). Propofol consumption was lower in patients given 0.1 mg⋅kg -1 (4.15 [3.51-5.44] mg·kg -1 ), 0.15 mg⋅kg -1 (3.54 [3.16-4.46] mg·kg -1 ), and 0.2 mg⋅kg -1 (2.74 [1.73-4.01] mg·kg -1 ) remimazolam than those given 0 mg⋅kg -1 (6.09 [4.99-7.35] mg·kg -1 ) remimazolam (all were P < .005). Time to anesthesia emergence did not differ significantly among the 5 groups.

CONCLUSIONS

For women undergoing hysteroscopic procedures, remimazolam at doses from 0.1 to 0.2 mg·kg -1 reduced the EC 50 of propofol inhibiting response to cervical dilation and the total propofol requirement. Whether the combination could improve perioperative outcomes deserves further investigation.

Circadian Variation in the Median Effective Dose of Epidural Ropivacaine for Labor Analgesia

Background: Labor pain perception has been demonstrated to exhibit a circadian rhythm with lower pain scores during the day compared with the night. This study aimed to determine and compare the median effective dose (ED₅₀) of ropivacaine in parturients having epidural labor analgesia during the day vs. during the night.

Methods: The study group consisted of 60 nulliparous healthy parturients who were assigned to one of two groups according to the time they requested labor analgesia: Day Group (7:01 am to 7:00 pm) and Night Group (7:01 pm to 7:00 am). A bolus of.15% ropivacaine was administered epidurally and effective analgesia was defined as the attainment of a visual analog scale (VAS) pain score ≤ 10 mm within 30 min. The dose of ropivacaine for the first parturient in each group was 18 mg. The dose for each subsequent parturient was varied with increments or decrements of 3 mg based on the response of the previous subject. The ED₅₀ was calculated using up-down sequential analysis. Probit regression was used to estimate the relative mean potency of ropivacaine between groups.

Results: The ED₅₀ (mean [95% CI]) of ropivacaine was lower in the Day Group (17.9 [16.5–19.4] mg) than in the Night Group (20.9 [19.2–22.7] mg) (P = 0.003). The estimate of relative potency for ropivacaine for the Night Group vs. the Day Group was 0.85 (95% CI:0.56–0.98).

Conclusions: Under the conditions of this study, the dose requirement for epidural ropivacaine for labor analgesia was ~ 15% greater during the night than during the day.

Clinical Trials Registration: Chinese Clinical Trial Registry (No.: ChiCTR1900025269. http://www.chictr.org.cn/showprojen.aspx?proj=36993).

Intraoperative management of combined general anesthesia and thoracic epidural analgesia: A survey among German anesthetists

BACKGROUND

Evidence concerning combined general anesthesia (GA) and thoracic epidural analgesia (EA) is controversial and the procedure appears heterogeneous in clinical implementation. We aimed to gain an overview of different approaches and to unveil a suspected heterogeneity concerning the intraoperative management of combined GA and EA.

METHODS

This was an anonymous survey among Members of the Scientific working group for regional anesthesia within the German Society of Anaesthesiology and Intensive Care Medicine (DGAI) conducted from February 2020 to August 2020.

RESULTS

The response rate was 38%. The majority of participants were experienced anesthetists with high expertise for the specific regimen of combined GA and EA. Most participants establish EA in the sitting position (94%), prefer early epidural initiation (prior to skin incision: 80%; intraoperative: 14%) and administer ropivacaine (89%) in rather low concentrations (0.2%: 45%; 0.375%: 30%; 0.75%: 15%) mostly with an opioid (84%) in a bolus-based mode (95%). The majority reduce systemic opioid doses intraoperatively if EA works sufficiently (minimal systemic opioids: 58%; analgesia exclusively via EA: 34%). About 85% manage intraoperative EA insufficiency with systemic opioids, 52% try to escalate EA, and only 25% use non-opioids, e.g. intravenous ketamine or lidocaine.

CONCLUSIONS

Although, consensus seems to be present for several aspects (patient's position during epidural puncture, main epidural substance, application mode), there is considerable heterogeneity regarding systemic opioids, rescue strategies for insufficient EA, and hemodynamic management, which might explain inconsistent results of previous trials and meta-analyses.

Comparison of opioid local anesthetic combination regimens using the number of self-administrated boluses in patient-controlled epidural analgesia after cesarean section: A retrospective single-center study

ABSTRACT

The aim of this study was to assess the efficacy of combined opioids by comparing four regimens of patient-controlled epidural analgesia (PCEA) after cesarean section.Parturient patients who underwent elective or emergent cesarean section under combined spinal and epidural anesthesia from April 2013 to March 2016 were retrospectively analyzed. Based on PCEA, they were assigned to one of 4 groups: local anesthetic alone (LA), epidural single morphine administration during surgery followed by local anesthetic alone (M), local anesthetic combined with fentanyl 10 μg/h (F10), or local anesthetic combined with fentanyl 20 μg/h (F20). The primary outcome was the number of PCEA boluses used. Secondary outcomes included the use of rescue analgesia, postoperative nausea and vomiting, and postoperative pruritus.A total of 250 parturients were analyzed. Whereas the number of PCEA boluses in the LA group was significantly higher than in the other combined opioid groups on the day of surgery and postoperative day 1 (LA: 3 [1-6] and 7 [4-9] vs M: 2 [0-4] and 4 [0-7] vs F10: 1 [0-4] and 3 [0-6] vs F20: 1 [0-3] and 2 [0-8], P = .012 and 0.010, respectively), within the combined opioid groups, the number was not significantly different. Significantly fewer patients in the F20 group required rescue analgesia on postoperative day 1 and 2 (25 and 55%) than those in the M (66 and 81%) and F10 (62 and 66%) groups (P < .001 and P = .007, respectively). Postoperative nausea and vomiting and pruritus were significantly higher in the M group (P < .008 and P = .024, respectively).The results of the present study suggest that local anesthetic alone after a single administration of morphine, or local anesthetic combined with fentanyl 10 μg/h would generally be adequate for PCEA, whereas local anesthetic combined with fentanyl 20 μg/h would be suitable for conventional epidural analgesia.

Epidural Anesthesia With Low Concentration Ropivacaine and Sufentanil for Percutaneous Transforaminal Endoscopic Discectomy: A Randomized Controlled Trial

Introduction: Percutaneous transforaminal endoscopic discectomy is a simple and effective treatment for lumbar intervertebral disc herniation, and local anesthesia is often applied in this kind of surgery in many developing countries, including China. However, many patients still feel excruciating pain under this condition. Epidural anesthesia with low-concentration ropivacaine has no impact on muscle strength, and patients might follow the surgeon well during operation. We hypothesize that epidural anesthesia is feasible for percutaneous transforaminal endoscopic discectomy. Methods: Two hundred patients with disc herniation who underwent percutaneous transforaminal endoscopic discectomy were randomized to receive either epidural anesthesia or local infiltration anesthesia. Primary outcome measures included the pain score, the cooperation degree, and patients' satisfaction. Mean arterial pressure and heart rate were also recorded. Results: Compared with the local anesthesia group, visual analog scale scores, mean arterial pressure, and heart rate were significantly lower in the epidural anesthesia group (P < 0.05), and patients' satisfaction was higher. There were no significant differences in the total operation time or blood loss between two groups. Conclusions: Epidural anesthesia with low-concentration ropivacaine and sufentanil is safe and effective for percutaneous transforaminal endoscopic discectomy. Clinical Trial Registration: ClinicalTrials.gov, identifier: ChiCTR-IOR-17011768.

Effects of Ropivacaine in Patient-Controlled Epidural Analgesia on Uterine Electromyographic Activities during Labor

Epidural analgesia is effective in relieving pain during labor. However, concerns as to compromised labor progress and outcomes arise. This study aimed to assess the effect of patient-controlled epidural analgesia (PCEA) with ropivacaine on uterine electromyography (EMG) activities and outcomes in labor. A total of 213 pregnant women were divided into three groups: the PCEA with ropivacaine group (n = 78), the PCEA with levobupivacaine group (n = 66), and a control group that did not receive PCEA (n = 69). Uterine EMG activities were recorded during the first stage of labor. Maternal and fetal outcomes also were assessed. The primary outcomes of this study were EMG activities. No significant differences were observed in patient demographics or neonatal weight among the three groups. Compared to the PCEA with levobupivacaine group, the control and PCEA with ropivacaine groups had lower rates of oxytocin administration (P < 0.05) and shorter durations of the first stage of labor (P < 0.05). For the EMG activities, the PCEA with ropivacaine group showed a higher power (P < 0.01) and higher peak frequency (P < 0.05) than the PCEA with levobupivacaine group. With ropivacaine, the EMG activities remained stable 30–120 min. Compared with levobupivacaine, the use of ropivacaine in PCEA has no suppressive effect on uterine EMG activities during the first stage of labor. In addition, ropivacaine leads to labor progress and delivery outcomes similar to those in the control group, as well as similar and favorable analgesic satisfaction with the use of levobupivacaine.

Effect of Thoracic Epidural Ropivacaine versus Bupivacaine on Lower Urinary Tract Function

Background

Thoracic epidural analgesia with bupivacaine resulted in clinically relevant postvoid residuals due to detrusor underactivity. This study aimed to compare the risk of bladder dysfunction with ropivacaine versus bupivacaine using postvoid residuals and maximum flow rates. Our hypothesis was that ropivacaine would result in lower postvoid residuals, because ropivacaine has been shown to have less effect on motor blockade.

Methods

In this single-center, parallel-group, randomized, double-blind superiority trial, 42 patients undergoing open renal surgery were equally allocated to receive epidural bupivacaine 0.125% or ropivacaine 0.2%, and 36 were finally included. Inclusion criterion was normal bladder function. Patients underwent urodynamic investigations preoperatively and during thoracic epidural analgesia. Primary outcome was the difference in postvoid residual preoperatively and during thoracic epidural analgesia postoperatively. Secondary outcomes were changes in maximum flow rate between and within the groups.

Results

Median difference in postvoid residual (ml) from baseline to postoperatively was 300 (range, 30 to 510; P &lt; 0.001) for bupivacaine and 125 (range, −30 to 350; P = 0.011) for ropivacaine, with a significant mean difference between groups (−175; 95% CI, −295 to −40; P = 0.012). Median difference in maximum flow rate (ml/s) was more pronounced with bupivacaine (−12; range, −28 to 3; P &lt; 0.001) than with ropivacaine (−4; range, −16 to 7; P = 0.025) with a significant mean difference between groups (7; 95% CI, 0 to 12; P = 0.028). Pain scores were similar. No adverse events occurred.

Conclusions

Postvoid residuals were significantly lower using ropivacaine compared to bupivacaine for thoracic epidural analgesia reflecting less impairment of detrusor function with ropivacaine.

Comparison of Epidural Analgesia Using 0.2% Bupivacaine and 0.2% Ropivacaine for the Management of Postoperative Pain in Major Orthopedic Surgery

Introduction

Ropivacaine is preferred over racemic bupivacaine for postoperative analgesia as it is less cardiotoxic and has high selectivity for sensory fibers. We aim to compare postoperative epidural analgesia using 0.2% bupivacaine and 0.2% ropivacaine in major lower limb orthopedic surgery.

Materials and Methods

In a prospective, randomized, double-blind study, 100 patients, aged 18-70 years, undergoing elective major lower limb orthopedic surgery under spinal anesthesia, were randomly allocated to receive either 7 ml ropivacaine 0.2% (Group R) or 7 ml bupivacaine 0.2% (Group B) for postoperative analgesia through a lumbar epidural catheter. The onset and duration of epidural analgesia, total epidural dose requirement, mean number of epidural topup, rescue analgesia, incidence of motor blockade, and adverse effects were recorded.

Results

No differences were noted in demographic data and hemodynamic variables in either group. The onset time of epidural analgesia was 10.46 min ± 0.68 (Group B) and 10.52 min ± 0.71 (Group R). The duration of analgesia was 253.10 ± 17.46 min (Group B) and 251.80 ± 15.77 min (Group R). The total analgesic dose requirement was 78.40 mg ± 6.93 in Group B while in Group R, it was 78.96 mg ± 6.79. Epidural topup requirement and the need for rescue analgesia were similar in both the groups. Motor blockade, hypotension, and nausea were noted more in Group B compared to Group R.

Conclusion

In patients undergoing major lower limb orthopedic surgery under subarachnoid block, epidural ropivacaine 0.2% produces effective postoperative analgesia similar to bupivacaine 0.2% with a distinct sensory-motor dissociation resulting in analgesia without motor blockade.

Double blind comparison of combination of 0.1% ropivacaine and fentanyl to combination of 0.1% bupivacaine and fentanyl for extradural analgesia in labour

BACKGROUND AND AIMS

Ropivacaine is considered as a safe alternative to bupivacaine for labor analgesia. The aim was to compare epidural ropivacaine and bupivacaine in intermittent doses for obstetric analgesia.

MATERIAL AND METHODS

In this prospective, randomized, double-blind study, 60 women in labor were randomly allocated to receive either bupivacaine 0.1% with fentanyl 2 μg/mL (BF), or ropivacaine 0.1% with fentanyl 2 μg/mL (RF). Bromage scale, loss of cold sensation to ether swab in midclavicular line, visual analog scale were used to test for motor block, sensory block and pain, respectively. Hemodynamic parameters, onset of analgesia, dose requirement of drug to produce analgesia, duration of labor, and incidence of side effects were also recorded. Data were expressed as mean ± standard deviation and analyzed using students unpaired t-test, Chi-square and Mann-Whitney U-tests at P < 0.05.

RESULTS

Both drugs were similar with respect to hemodynamic stability, onset of analgesia, quality of analgesia, sensory blockade, neonatal outcome, requirement of drugs, duration of labor, and incidence of side effects. Three parturient in bupivacaine (B-F) group had a motor block of Bromage 1 and were delivered using forceps. None of the parturient in ropivacaine (R-F) group had any motor block, and all had spontaneous vaginal delivery, but this difference was not statistically significant (P = 0.081).

CONCLUSIONS

Bupivacaine and ropivacaine provide equivalent analgesia in low (0.1%) concentration.

Epidural Analgesia With Bupivacaine and Fentanyl Versus Ropivacaine and Fentanyl for Pain Relief in Labor: A Meta-Analysis

The aim of this study was to compare the efficacy and safety of the combinational use of bupivacaine and fentanyl versus ropivacaine and fentanyl in epidural analgesia for labor. Multiple electronic databases were searched by using appropriate MeSH terms, and keywords for original research papers published before October 2014. Meta-analyses were based on mean differences between the groups as well as odds ratios. Statistical heterogeneity was tested by I² index. Fifteen randomized controlled trials, recruiting 2097 parturient mothers overall, were selected for the meta-analyses. Concentrations of the preparations used (weight/volume; mean and standard deviations) were bupivacaine 0.1023% ± 0.0375%, ropivacaine 0.1095% ± 0.042%, and fentanyl 0.00021% ± 0.000089%. There were no statistically significant differences between both the combinations in the mean change in Visual Analog Score for pain during labor, incidence of instrumental or cesarean delivery, neonate Apgar score of <7, maternal satisfaction, duration of either first or second stage of labor, oxytocin use for induction, onset of analgesia, and duration of analgesia. Women who received ropivacaine and fentanyl had significantly lower incidence of motor blocks (odds ratio [95% CI] = 0.38 [0.30, 0.48] P < 0.00001, fixed effect and 0.38 [0.27, 0.54] P < 0.0001, random effects I² 30%) when compared with women who received bupivacaine and fentanyl. Incidence of side effects was similar for both the combinations. Analgesia with ropivacaine in combination with fentanyl at 0.1%:0.0002% ratio for labor pain relief is associated with lower incidence of motor blocks in comparison with analgesia with bupivacaine and fentanyl at similar ratio (0.1%: 0.0002%).

Epidural analgesia with amide local anesthetics, bupivacaine, and ropivacaine in combination with fentanyl for labor pain relief: a meta-analysis

Background

The study compares the effectiveness of bupivacaine and fentanyl (BUPI-FEN) and ropivacaine and fentanyl (ROPI-EFN) in epidural analgesia for labor pain through a meta-analysis of relevant randomized clinical trials.

Material/Methods

Multiple electronic databases were searched using appropriate MeSH terms and keywords for original English language research papers published between 1990 and March 2014. Meta-analyses results were based on the mean differences between the groups as well as odds ratios where appropriate. Statistical heterogeneity amongst the included studies was tested by I² index.

Results

Nine studies that met the inclusion criteria were selected for analysis which consisted of 556 parturient patients. The duration of the second stage of labor was significantly shorter in the BUPI-FEN group by a mean of −6.87 (−10.98, −2.77; P<0.002). On the other hand, the ROPI-FEN group had a significantly lower incidence of motor blockade by a mean of 0.31 (0.18, 0.51; P<0.00001). A positive relationship between the amide local anesthetic concentration and the number of women having motor blockade was observed, but a negative relationship between fentanyl concentration and the number of women experiencing a motor block. Moreover, a positive correlation was found between the concentration of ropivacaine and the incidence of instrumental delivery and between the concentration of bupivacaine and the incidence of cesarean delivery.

Conclusions

In combination with fentanyl, bupivacaine and ropivacaine exhibit comparable efficacy and safety. However, BUP-FEN analgesia led to a shortened second-stage labor and ROPI-FEN resulted in a significantly lower incidence of motor block.

0.2% ropivacaine with fentanyl in the management of labor analgesia: A case study of 30 parturients

BACKGROUND

Epidural infusion of 0.2% ropivacaine is recommended by the manufacturers for labor analgesia.

AIMS

The aim of this study is to evaluate the analgesic efficacy, degree of motor blockade, obstetric outcome in the form of incidence of normal vaginal, assisted vaginal and lower segment cesarean section.

SETTINGS AND DESIGN

Pilot study.

MATERIALS AND METHODS

In this pilot study, 30 nulliparous parturients in active labor had epidural analgesia established using 0.2% ropivacaine with 25 mcg fentanyl for initiation when cervical dilatation was 3-4 cm and then analgesia was maintained with 0.2% ropivacaine at 10 ml/h till the delivery of baby.

STATISTICAL ANALYSIS

It was done by Wilcoxon sign rank test and paired t-test as applicable.

RESULTS

There was a significant difference (P < 0.05) between prebolus, postbolus and postinfusion with respect to visual analog score. There was a significant difference (P > 0.05) between prebolus, postbolus, and postinfusion with respect to Bromage motor score, (Wilcoxon sign rank test). Six out of 30 paturients complained of tingling and heaviness in lower limbs after continuous infusion of 2-2.5 h.

CONCLUSION

We conclude that 0.2% ropivacaine (8 ml) with fentanyl 25 mcg is good for initiation of ambulatory labor analgesia. But for maintenance of labor analgesia lower concentration of ropivacaine may be preferred.

Patient-controlled epidural analgesia after Caesarean section: levobupivacaine 0.15% versus ropivacaine 0.15% alone or combined with fentanyl 2 µg/ml: a comparative study

INTRODUCTION

The aim of this study was to compare the postoperative analgesic efficacy of epidural ropivacaine 0.15%, levobupivacaine 0.15% and ropivacaine 0.15% plus fentanyl 2 µg/ml, used with a patient-controlled epidural analgesia (PCEA) device after Caesarean section.

MATERIAL AND METHODS

Sixty women undergoing elective Caesarean section under combined spinal-epidural anaesthesia were enrolled. Postoperatively, patients received PCEA with either ropivacaine or levobupivacaine 0.15% (basal rate 6 ml/h, bolus 5 ml/20 min), or ropivacaine 0.15% plus fentanyl 2 µg/ml (basal rate 6 ml/h, bolus 4 ml/20 min). Sympathetic and sensory level of analgesia, motor ability (Bromage 0-3), and pain scores at rest, movement and cough (VAS 0-10), haemodynamic parameters, oxygenation, side effects and total doses of local anaesthetic were documented every 6 h for 24 h. Patient satisfaction was assessed using a descriptive scale.

RESULTS

No significant difference was observed in pain scores at all time intervals. A significantly higher sympathetic and sensory blockade occurred with levobupivacaine and ropivacaine 0.15% compared to ropivacaine 0.15% plus fentanyl, with no significant difference in total local analgesic consumption at 24 h (p = 0.08). Rescue analgesic requirements did not differ between the groups (p = 0.8) while patients' satisfaction was significantly higher in the ropivacaine 0.15% plus fentanyl group (p = 0.02). Haemodynamics, oxygenation, nausea, pruritus and numbness did not differ between the groups.

CONCLUSIONS

Dilute local anaesthetic solutions provided satisfactory postoperative analgesia after Caesarean section when used with a PCEA device. The combination of ropivacaine 0.15% with fentanyl 2 µg/ml appeared superior, since it provided higher patient satisfaction with statistically equal pain scores and local anaesthetic consumption.

Modern neuraxial labor analgesia: options for initiation, maintenance and drug selection

In the present review we outline the state-of-the-art of neuraxial analgesia. As neuraxial analgesia remains the gold standar of analgesia during labor, we review the most recent literature on this topic. The neuraxial analgesia techniques, types of administration, drugs, adjuvants, and adverse effects are investigated from the references. Most authors would agree that central neuraxial analgesia is the best form to manage labor pain. When neuraxial analgesia is administered to the parturient in labor, different management choices must be made by the anesthetist: how will we initiate analgesia, how will analgesia be maintained, which local anesthetic will we use for neuraxial analgesia and which adjuvant drugs will we combine? The present manuscript tries to review the literature to answer these questions.

Randomized controlled trial of patient-controlled epidural analgesia after orthopaedic surgery with sufentanil and ropivacaine 0.165% or levobupivacaine 0.125%

BACKGROUND

Ropivacaine, and to a lesser extent also levobupivacaine, is commonly used for postoperative epidural analgesia. Despite ED50 data suggesting a potency difference between these drugs, clinically they can be difficult to distinguish. As a consequence, it is unclear which concentration of each drug to use when comparing them for long-term analgesia.

METHODS

One hundred patients undergoing total hip or knee replacement were selected to participate in a double-blind randomized study comparing ropivacaine 0.165% with levobupivacaine 0.125% to which was added sufentanil 1 microg ml(-1) for postoperative analgesia by the epidural route. Patient-controlled epidural analgesia (PCEA) was offered for 48 h. After the first 24 h, the basal infusion was omitted.

RESULTS

Pain scores both at rest and on mobilization were similar between both groups. The volume of local anaesthetic solution consumed during the first 48 h after surgery was 25% higher in those patients receiving ropivacaine (P=0.02). Patients receiving ropivacaine made a mean (SD) of 38.5 (16) PCEA demands in the first 48 h after surgery compared with 28 (13) in the levobupivacaine group (P=0.04).

CONCLUSIONS

Both local anaesthetics provided effective postoperative analgesia but, even in a 25% weaker concentration, a small volume of levobupivacaine and opiate substance was consumed. These differences may be explained by a potency difference or by the duration of action of levobupivacaine.

Local Anesthetics and Mode of Delivery: Bupivacaine Versus Ropivacaine Versus Levobupivacaine

BACKGROUND

The influence of the labor epidural local anesthetic (LA) on mode of delivery has not been adequately studied. In this study, we sought to determine if there is a difference in mode of delivery among parturients who receive epidural bupivacaine, ropivacaine, or levobupivacaine.

METHODS

Nulliparous women at term requesting labor analgesia with a cervical dilation <5 cm were randomized to receive epidural bupivacaine, ropivacaine, or levobupivacaine. Analgesia was initiated with a bolus of 15 mL of 0.0625% of the assigned LA with fentanyl 2 microg/mL. Analgesia was maintained with an infusion of the same solution at 10 mL/h. The primary endpoint was the operative delivery rate (instrumental assisted vaginal delivery plus cesarean delivery).

RESULTS

Ninety-eight women received bupivacaine, 90 ropivacaine, and 34 levobupivacaine (before it was removed from the US market). There was no significant difference in the operative delivery rate (bupivacaine = 46%, ropivacaine = 39%, and levobupivacaine = 32%, P = 0.35) among groups. There was less motor block in the levobupivacaine group when compared with the ropivacaine and bupivacaine groups, P < 0.05. There was no significant difference in the duration of the first or second stage of labor, the total dose of LA received per hour of labor, or neonatal outcome among groups.

CONCLUSIONS

Bupivacaine, ropivacaine, and levobupivacaine all confer adequate labor epidural analgesia, with no significant influence on mode of delivery, duration of labor, or neonatal outcome.

Novel local anaesthetics and novel indications for local anaesthetics

Research into local anaesthetic mechanisms over the past few years has focused on two main issues. First, attention has focused on development of compounds with fewer side effects, better sensory/motor separation and longer duration of action; this has resulted in the introduction of ropivacaine and levobupivacaine into clinical practice. These agents have a lesser cardiotoxic effect than older compounds, and ropivacaine may in addition offer better sensory/motor separation. Several other compounds, including tonicaine and sameridine, are under investigation. In addition, the local anaesthetic properties of amitryptiline are being studied, and liposome encapsulation of local anaesthetics appears able to confer new pharmacokinetic properties on common drugs. Second, the molecular basis for several local anaesthetic actions that are not mediated by sodium channels has become a topic of interest. The mechanisms that underlie anti-inflammatory and antithrombotic actions are at present being unravelled. How local anaesthetics potentiate antitumour agents, protect neuronal tissue and prevent bronchial reactivity is less clear, but the potential clinical benefits of these effects deserve further exploration.

Epidural ropivacaine -- where are the benefits? A prospective, randomized, double-blind trial in patients with retropubic prostatectomy

BACKGROUND

In comparison with bupivacaine, ropivacaine exhibits comparable anaesthetic effects but with less motor impairment and systemic toxicity. However, the analgesic potency may differ. For example, ropivacaine during obstetric epidural analgesia provides an approximately 40% lower analgesic potency than bupivacaine. Equal visual analogue pain scores require significantly higher dosages of ropivacaine, and general statements about a favourable benefit-risk profile relative to that of bupivacaine may therefore have limited clinical impact. We addressed this topic in a male pain model by evaluating the analgesic efficacy of epidural ropivacaine 0.2% vs. bupivacaine 0.125% after retropubic prostatectomy.

METHODS

Forty patients scheduled for retropubic prostatectomy were randomly assigned to two groups (20 patients per group). In a double-blind prospective design, patient-controlled lumbar epidural analgesia was provided by ropivacaine 0.2% in the ropivacaine group and by bupivacaine 0.125% in the bupivacaine group. The primary endpoint was the total amount of local anaesthetic consumption. The secondary endpoints were the numeric rating scale scores for rest and dynamic pain and the degree of motor impairment.

RESULTS

Ropivacaine consumption was 60% higher (mean +/- standard deviation, 1372.5 +/- 108.3 mg) than that of bupivacaine (852 +/- 75.2 mg) (P < 0.001). There were no significant differences in the numeric rating scale scores and motor impairment.

CONCLUSIONS

In male patients, lumbar epidural administration of ropivacaine 0.2% after retropubic prostatectomy does not appear to provide benefits over bupivacaine 0.125%. Moreover, in view of the significantly higher drug requirements, general statements focusing on the favourable therapeutic index of ropivacaine may require critical analysis, at least during epidural administration.

Effect of sufentanil on minimum local analgesic concentrations of epidural bupivacaine, ropivacaine and levobupivacaine in nullipara in early labour

BACKGROUND

The aim was to assess the effect of epidural sufentanil on relative analgesic potencies of epidural bupivacaine, ropivacaine and levobupivacaine by determining the minimum local analgesic concentrations during labour.

METHODS

In a randomised, double-blind study, 171 parturients were allocated to one of six groups receiving a 10-mL bolus of bupivacaine, ropivacaine or levobupivacaine alone or with sufentanil 0.75 microg/mL. The concentration of local anaesthetic was determined by the response of the previous parturient using up-down sequential allocation starting at a concentration of 0.13% wt/vol with a testing interval of 0.01%. Effective analgesia was defined as a visual analogue pain score < or = 15/100 mm within 30 min and lasting for 30 min. Median effective concentrations were estimated and two-sided P < 0.05 was significant.

RESULTS

Local anaesthetic concentration, use of sufentanil and local anaesthetic drug were independent significant predictors of effective and ineffective analgesia. Bupivacaine was significantly more potent than levobupivacaine and ropivacaine. The relative potency ratios without sufentanil of 0.77:0.83:1.00 were reduced to 0.36:0.38:1.00 by the addition of sufentanil. The major factor influencing local anaesthetic requirements was the addition of sufentanil, which reduced overall requirements by a factor of 4.2 (95% CI 3.6-4.8); this effect was proportionately more enhanced for bupivacaine.

CONCLUSIONS

Local anaesthetic requirements for bupivacaine, levobupivacaine and ropivacaine follow an analgesic potency hierarchy. Any potency differences are small when compared to the effect of sufentanil, which resulted in a four-fold reduction in local anaesthetic requirements. Sufentanil may also enhance the potency differences between bupivacaine and the two S-enantiomer agents.

Intraarticular Bupivacaine-Clonidine-Morphine Versus Femoral-Sciatic Nerve Block in Pediatric Patients Undergoing Anterior Cruciate Ligament Reconstruction

We hypothesized that combined femoral-sciatic nerve block (FSNB) offers better analgesia with fewer side effects than intraarticular infiltration (IA) in children undergoing anterior cruciate ligament (ACL) reconstruction. Thirty-six children undergoing ACL reconstruction were randomized to FSNB or IA. FSNB patients had FSNB with bupivacaine (0.125%)-clonidine (2 microg/kg), whereas IA patients received bupivacaine (0.25%)-clonidine (1 microg/kg)-morphine (5 mg). Postoperatively, analgesia was provided with patient-controlled analgesia and rescue morphine. Patient demographics were similar. FSNB patients required less intraoperative fentanyl (50 +/- 40 microg versus 80 +/- 50 microg; P = 0.04). Visual analog scale score for FSNB was smaller than IA in the recovery room (1.8 +/- 3 versus 5.4 +/- 3; P = 0.0002) and during the first 24 h (1.6 +/- 1 versus 2.9 +/- 2; P = 0.01)). FSNB morphine use in the first 18 h was less (7 +/- 13 mg versus 21 +/- 21 mg; P = 0.03). Fewer FSNB patients vomited (11% versus 50%; P = 0.03). IA patients required morphine patient-controlled analgesia sooner. After ACL reconstruction in children, FSNB with bupivacaine-clonidine provides better analgesia with fewer side effects than IA with bupivacaine-clonidine-morphine.

Comparison of maternal and neonatal outcomes with epidural bupivacaine plus fentanyl and ropivacaine plus fentanyl for labor analgesia

BACKGROUND

Several studies have been performed to find a safe method of labor analgesia with minimal side effects and toxicity in mother and fetus. We aimed to compare the efficacy and side effects of epidural bupivacaine plus fentanyl and ropivacaine plus fentanyl at low concentrations.

METHOD

Forty ASA I-II parturients' were included in this prospective, double-blind, trial and randomized to receive either bupivacaine or ropivacaine for labor analgesia. Analgesia was initiated with 8 mL of 0.125% solution plus fentanyl 50 microg and maintained with a continuous infusion of 0.0625% solution with fentanyl 2 microg/mL.

RESULTS

There were no differences in pain scores, total dose of local anesthetics used, sensory or motor blockade, labor duration, mode of delivery, side effects, patient satisfaction, or neonatal outcome between the two local anesthetics at these dosages, but at the end of the second stage and delivery, adequate analgesia quality could not be ensured.

CONCLUSION

We found no major advantage of continuous epidural infusion of ropivacaine 0.0625% plus fentanyl 2 microg/mL over bupivacaine 0.0625% plus fentanyl 2 microg/mL for labor analgesia. We believe that different methods or dosages may be tried in order to improve comfort at the second stage of labor and the delivery.

Patient-controlled epidural analgesia during labor using ropivacaine and fentanyl provides better maternal satisfaction with less local anesthetic requirement

PURPOSE

To test the hypothesis that patient-controlled epidural analgesia (PCEA) using ropivacaine and fentanyl provides better maternal satisfaction and less anesthetic requirement than conventional continuous epidural infusion (CEI) during labor, we studied 58 uncomplicated parturients (singleton, vertex presentation).

METHODS

After establishing effective epidural analgesia with 11 ml of 0.2% ropivacaine, all parturients were randomly divided into one of two groups: the PCEA group (n = 29) or the CEI group (n = 29). In the PCEA group, the pump was initiated to deliver a basal infusion at 6 ml x h(-1) and a demand dose of 5 ml; the lockout interval was 10 min, and there was a 31 ml x h(-1) limit. The drugs used were 0.1% ropivacaine + fentanyl 2 microg x ml(-1). In the CEI group, epidural analgesia was maintained with the same solution as the PCEA group at a constant rate of 10 ml x h(-1). If parturients requested additional analgesia in the CEI group, we added 8 ml of epidural 0.2% ropivacaine without fentanyl.

RESULTS

Parturients' demographic data, such as duration of labor, mode of delivery, Apgar score, and umbilical arterial pH did not differ between the two groups. However, the hourly requirement of ropivacaine was significantly less in the PCEA group than in the CEI group (9.3 +/- 2.5 vs. 17.6 +/- 7.6 mg x h(-1); P < 0.05). Parturients' satisfaction assessed by the Visual Analogue Scale tended to be higher in the PCEA group than in the CEI group. Side effects such as nausea, hypotension, and itching were similar for the two groups.

CONCLUSION

We found that PCEA was an effective means of providing optimal analgesia, with better satisfaction during labor and less local anesthetic requirement.

Current status and clinical relevance of studies of minimum local-anaesthetic concentration (MLAC)

PURPOSE OF REVIEW

Studies comparing the effects of epidural local anaesthetics have been limited by the lack of knowledge of their relative potencies. In 1995 the concept of the minimum local-anaesthetic concentration (MLAC) was introduced, this has been defined primarily as the median effective analgesic concentration in the first stage of labour. Pharmacologically, this model aims to determine equipotent analgesic concentrations of local anaesthetics, to compare motor effects and to evaluate the relative toxicity during labour. However, results of recent MLAC studies are not uniform and rather confusing, and thus, the basic validity of the MLAC concept for determining local-anaesthetic potency is increasingly discussed.

RECENT FINDINGS

MLAC studies have postulated that ropivacaine is up to 40% less potent than bupivacaine, but as potent as levo-bupivacaine. Intriguingly, bupivacaine has been shown to be as effective as levo-bupivacaine in identical experimental protocols. Modified MLAC studies resulted additionally in local anaesthetic-sparing effects of epidural/intrathecal opioids, clonidine and epinephrine. MLAC studies have also been applied to compare the relative analgesic as well as relative motor-blocking potency of local anaesthetics.

SUMMARY

Relative differences in local anaesthetics' potencies derived from MLAC examinations are meaningful and correct from the pharmacological point of view, but they cannot simply be transferred to daily clinical practice. Thus, MLAC values should not be misinterpreted as these data are not suggested to be suitable to define and quantify the pharmacodynamics of local anaesthetics, nor to unequivocally predict their toxicological profile in clinically relevant concentrations.

Patient-controlled epidural analgesia for labor pain: effect on labor, delivery and neonatal outcome of 0.125% bupivacaine vs 0.2% ropivacaine

The objective was to evaluate the influence of patient-controlled epidural analgesia (PCEA) using low doses of bupivacaine vs. ropivacaine, on labor pain, motor blockade, progression of labor, delivery and neonatal outcome. This randomized double blind study included 565 parturients. All received a 5-mL/h infusion and PCEA (5-mL boluses with a 20-min lockout, maximum volume 20 mL/h) of either 0.125% bupivacaine (n = 313: 165 nulliparous, 148 parous) or 0.2% ropivacaine (n = 252: 113 nulliparous, 139 parous). Pain score, lower limb motor block, sensory levels, local analgesic doses required, hemodynamic parameters, side effects and complications were assessed. Obstetric variables included cervical dilation at epidural insertion, incidence of ruptured membranes and their duration, use of oxytocin, fetal heart rate changes, duration of labor, mode and outcome of delivery, and use of invasive and non-invasive fetal monitoring. Neonatal characteristics included birth weight, Apgar scores, umbilical artery pH, serum bilirubin, hypoglycemia, need for assisted ventilation, sepsis or sepsis study, feeding difficulties and respiratory distress syndrome. Ropivacaine 0.2% was equianalgesic with 0.125% bupivacaine, but produced less motor block (P < 0.0001). There were no significant differences, however, in duration of labor, delivery type or neonatal outcome.

Epidural Infusions of Ropivacaine and Bupivacaine for Labor Analgesia: A Randomized, Double-Blind Study of Obstetric Outcome

Studies have shown better obstetric outcome when ropivacaine 0.25% was used for labor epidural analgesia compared with bupivacaine 0.25%, but it is controversial whether there is any difference at smaller concentrations. In a prospective, double-blind trial, we randomized 350 ASA physical status I and II parturients with term cephalic singleton pregnancies to receive epidural labor analgesia using ropivacaine or bupivacaine. Analgesia was initiated with a 0.25% solution and maintained with a continuous infusion of a 0.1% solution with fentanyl 0.0002%. Supplementary boluses of 0.25% solution were given when requested. Labor was managed according to institutional standard labor ward protocols. Among patients who delivered vaginally, the duration of the first stage of labor was shorter in the ropivacaine group (median, 520 min; interquartile range, 377-745 min) compared with the bupivacaine group (645 min; interquartile range, 460-820 min; P = 0.009), but there was no difference in any other obstetric or neonatal outcomes. The mode of delivery was similar between groups, with operative (instrumental vaginal and cesarean) delivery rates of 61.8% (95% confidence interval, 54.4%-68.8%) in the ropivacaine group and 58.4% (95% confidence interval, 50.9%-65.5%) in the bupivacaine group (P = 0.72).

IMPLICATIONS

In a randomized-controlled study, we found no major outcome advantage of continuous epidural infusion of ropivacaine 0.1% with fentanyl 0.0002% over bupivacaine 0.1% with fentanyl 0.0002% for labor analgesia. Although ropivacaine was associated with a shorter first stage of labor, the relative difference is probably of limited clinical importance, and there was no difference in the mode of delivery.

Comparison of ropivacaine with a combination of ropivacaine and fentanyl for the caudal epidural anaesthesia of mares

Two groups of six mares aged from eight to 18 years were anaesthetised by caudal epidural injections of ropivacaine (0.5 per cent, 0.1 mg/kg) or a combination of ripovacaine (0.08 mg/kg) and fentanyl (100 microg) in a randomised study. The onset of anaesthesia was significantly more rapid (P<0.001) and it lasted significantly longer (P<0.001) in the group anaesthetised with the combination of drugs. The surgical comfort scores of the group anaesthetised with the combination were higher than those of the group anaesthetised with ropivacaine alone (P<0.001), and the quality of intraoperative analgesia, as assessed by the surgeon, was significantly improved. There were no differences between the groups in their average scores for the levels of ataxia and sedation, in their behaviour, or in the incidence of side effects.

Comparison of patient-controlled epidural bolus administration of 0.1% ropivacaine and 0.1% levobupivacaine, both with 0.0002% fentanyl, for analgesia during labour

The aim of the study was to compare the relative potencies and clinical characteristics of epidural ropivacaine and levobupivacaine in labour using patient-controlled epidural analgesia (PCEA). In a randomised double-blinded study, 60 ASA I or II primigravidae requesting epidural analgesia in early labour were allocated to receive either 0.1% ropivacaine with fentanyl 0.0002% or 0.1% levobupivacaine with 0.0002% fentanyl via a patient-controlled analgesia pump. Analgesia was established with 15 ml of study solution and maintained using 5-ml boluses of study solution with a 5-min lockout interval. There were no significant differences in onset time, duration and quality of analgesia, motor and sensory blockade, local anaesthetic consumption, mode of delivery, neonatal outcome or maternal satisfaction between the groups. We conclude that 0.1% ropivacaine with 0.0002% fentanyl and 0.1% levobupivacaine with 0.0002% fentanyl are clinically indistinguishable for labour analgesia and appear pharmacologically equipotent when using PCEA.

Benefit-Risk Assessment of Ropivacaine in the Management of Postoperative Pain

Ropivacaine is a long-acting amide-type local anaesthetic, released for clinical use in 1996. In comparison with bupivacaine, ropivacaine is equally effective for subcutaneous infiltration, epidural and peripheral nerve block for surgery, obstetric procedures and postoperative analgesia. Nevertheless, ropivacaine differs from bupivacaine in several aspects: firstly, it is marketed as a pure S(-)-enantiomer and not as a racemate, and secondly, its lipid solubility is markedly lower. These features have been suggested to significantly improve the safety profile of ropivacaine, and indeed, numerous studies have shown that ropivacaine has less cardiovascular and CNS toxicity than racemic bupivacaine in healthy volunteers. Extensive clinical data have demonstrated that epidural 0.2% ropivacaine is nearly identical to 0.2% bupivacaine with regard to onset, quality and duration of sensory blockade for initiation and maintenance of labour analgesia. Ropivacaine also provides effective pain relief after abdominal or orthopaedic surgery, especially when given in conjunction with opioids or other adjuvants. Nevertheless, epidurally administered ropivacaine causes significantly less motor blockade at low concentrations. Whether the greater degree of blockade of nerve fibres involved in pain transmission (Adelta- and C-fibres) than of those controlling motor function (Aalpha- and Abeta-fibres) is due to a lower relative potency compared with bupivacaine or whether other physicochemical properties or stereoselectivity are involved, is still a matter of intense debate. Recommended epidural doses for postoperative or labour pain are 20-40 mg as bolus with 20-30 mg as top-up dose, with an interval of >or=30 minutes. Alternatively, 0.2% ropivacaine can be given as continuous epidural infusion at a rate of 6-14 mL/h (lumbar route) or 4-10 mL/h (thoracic route). Preoperative or postoperative subcutaneous wound infiltration, during cholecystectomy or inguinal hernia repair, with ropivacaine 100-175 mg has been shown to be more effective than placebo and as effective as bupivacaine in reducing wound pain, whereby the vasoconstrictive potency of ropivacaine may be involved. Similar results were found in peripheral blockades on upper and lower limbs. Ropivacaine shows an identical efficacy and potency to that of bupivacaine, with similar analgesic duration over hours using single shot or continuous catheter techniques. In summary, ropivacaine, a newer long-acting local anaesthetic, has an efficacy generally similar to that of the same dose of bupivacaine with regard to postoperative pain relief, but causes less motor blockade and stronger vasoconstriction at low concentrations. Despite a significantly better safety profile of the pure S(-)-isomer of ropivacaine, the increased cost of ropivacaine may presently limit its clinical utility in postoperative pain therapy.

Ropivacaine and Fentanyl Concentrations in Patient-Controlled Epidural Analgesia During Labor: A Volume-Range Study

We enrolled nulliparous women in induced labor in a randomized study to determine whether increasing the concentration of the solution used in a patient-controlled epidural analgesia (PCEA) device was required as labor progressed. Patients were assigned to 6 groups (n = 25 in each group), receiving ropivacaine/fentanyl in concentrations of either 0.1%/0.5 microg/mL or 0.2%/1 microg/mL via a PCEA pump. Three groups received boluses of 12, 16, or 20 mL dilute solution in early labor (uterine contractions every 3 min and 4-cm cervical dilation) then 6, 8, and 10 mL concentrated solution in late labor. Three other groups received boluses of 12, 16, or 20 mL dilute solution during both periods. The lockout interval was 25 min. The primary outcome was time until the first request for staff-administered analgesia supplement. Hourly assessments included pain scores on a visual analog scale (VAS) graded from 0 to 10, satisfaction scores, arterial blood pressure, motor block intensity, and the upper sensory level of epidural anesthesia. Patients, midwives, and the observer were unaware of study solutions and PCEA settings. The maximum pain score was defined as the highest score experienced by each patient during each period. Duration of analgesia was defined as the time from the start of each period to the first injection of rescue analgesia and was compared using a survival analysis. There were no differences among the groups with regard to demographic and obstetric variables, arterial blood pressure, motor block intensity, upper sensory level, or satisfaction scores. At least 75% of the women rated their satisfaction as either good or excellent during each period. During late labor, the maximum pain score was lower in the group receiving 20 mL dilute solution compared with the group receiving 6 mL concentrated solution. Maximum pain score was not significantly different between 20 mL dilute solution and 10 mL concentrated solution (difference between VAS values = -0.4; 95% confidence limits, -1.599 and 0.799; P = 0.5055). During late labor, the duration of analgesia was longer in groups receiving 20 mL dilute solution (99 +/- 4 min) (mean +/- SD) than in those receiving 12 mL (77 +/- 30 min) and 16 mL (80 +/- 23 min). Duration of analgesia did not differ between groups receiving 20 mL and 10 mL (92 +/- 23 min) or between groups receiving 12 mL and 6 mL (78 +/- 30 min) of each respective solution. Duration of analgesia was longer in the groups receiving 8 mL concentrated solution (94 +/- 16 min) than in those receiving 16 mL dilute solution. We concluded that 0.1%/0.5 microg/mL ropivacaine/fentanyl was effective throughout labor when 20 mL was injected with each PCEA demand. With 16 mg ropivacaine and 8 microg fentanyl, the duration of analgesia was prolonged by doubling the concentration when labor became active. When 12 mg ropivacaine and 6 microg fentanyl were injected at each demand, analgesia was less satisfactory and doubling the concentration was not clinically effective. These results suggest that the effectiveness of PCEA is dependent on drug mass rather than the volume or concentration administered with each successful pump demand.

IMPLICATIONS

There is no clinical reason for increasing the concentration of the patient-controlled epidural analgesia (PCEA) solution when labor becomes active provided that an effective dose is already being administered with each demand. The quality of PCEA depends on the drug mass given with each demand rather than the concentration of the pump solution.

The Effects of S(???)-, R(+)-, and Racemic Bupivacaine on Lysophosphatidate-Induced Priming of Human Neutrophils

Local anesthetics modulate inflammatory responses and may therefore be potentially useful in mitigating perioperative inflammatory injury. The inflammatory modulating effects of S(-)-bupivacaine are not known. Therefore, we compared the effects of S(-)-bupivacaine, R(+)-bupivacaine, and racemic bupivacaine on neutrophil function and receptor signaling. Priming (by lysophosphatidic acid [LPA]) and activation (by N-formylmethionine-leucyl-phenylalanine) of superoxide release by isolated human neutrophils was studied by using a cytochrome c-reduction assay. LPA receptor signaling in Xenopus oocytes was studied by using voltage clamp. All three local anesthetics were without effect on activation. S(-)-Bupivacaine inhibited priming more than did racemic bupivacaine; R(+)-bupivacaine was without effect. At 10(-4) M, S(-)-bupivacaine inhibited approximately 50%. Comparable results were obtained in our recombinant model, where S(-)-bupivacaine most effectively inhibited LPA signaling. Compared with racemic bupivacaine and other anesthetics, S(-)-bupivacaine appears particularly effective in suppressing neutrophil priming, a process responsible in part for the overactive neutrophil response.

IMPLICATIONS

Overactive inflammatory responses underlie several perioperative disorders. Compared with racemic bupivacaine and other anesthetics, S(-)-bupivacaine appears particularly effective in suppressing neutrophil priming, a process responsible in part for the overactive neutrophil response.

Epidural levobupivacaine, ropivacaine and bupivacaine in combination with sufentanil in early labour: a randomized trial

BACKGROUND AND OBJECTIVE

To evaluate the efficacy, delay and duration of analgesia of three equianalgesic epidural doses of levobupivacaine, ropivacaine and bupivacaine during the first stage of labour.

METHODS

One hundred and twenty-nine healthy primigravida in spontaneous labour who requested epidural analgesia were enrolled in a randomized observer-blinded study. Parturients were allocated to receive epidural levobupivacaine 0.0625%, ropivacaine 0.1% or bupivacaine 0.06259%. Sufentanil 10 microg was added to all solutions; the total volume of epidural solution was 20 mL. Pain was measured using a 100 mm visual analogue pain scale immediately before the epidural block, and at 5, 10, 15, 20 and 30 min thereafter. Motor block was evaluated using a modified Bromage scoring system. The adequacy of motor function for ambulation was also evaluated. Delay of analgesia was the time interval between the injection of the solution and the first painless contraction. Duration of analgesia was the time from the first painless contraction to the parturients' requests for further analgesia.

RESULTS

Twelve parturients failed to complete the study. Eleven parturients had inadequate analgesia (four in Group Levobupivacaine, four in Group Ropivacaine and three in Group Bupivacaine; P > 0.05). Data was analysed from 34 parturients in Group Levobupivacaine, from 37 in Group Ropivacaine and from 35 in Group Bupivacaine. There were no differences in the delay of analgesia or in the number of parturients who were able to walk unaided. Levobupivacaine and ropivacaine produced more prolonged analgesia than bupivacaine (114 and 119 min, respectively, versus 89 min; P < 0.01).

CONCLUSIONS

During early labour, equipotent low concentrations of levobupivacaine, ropivacaine and bupivacaine, all with the addition of sufentanil 10 microg, produced similar pain relief and motor block, but levobupivacaine and ropivacaine produced a longer lasting analgesia. About 10% of parturients had inadequate analgesia with a single bolus of the tested solutions.