Comparison of ropivacaine and bupivacaine for epidural analgesia during labor]

OBJECTIVES: To compare the analgesic efficacy and level of motor block using two local anesthetics, ropivacaine and bupivacaine, during labor. MATERIAL AND METHODS: Sixty nulliparous women were enrolled during labor after full-term pregnancies. They were randomly assigned to receive epidural analgesia with ropivacaine (group R) or bupivacaine (group B). Group R patients received 10 ml of 0.18% ropivacaine with 5 microgram/ml of fentanyl followed by continuous epidural infusion of 0.1% ropivacaine with 2 microgram/ml of fentanyl at a rate of 10 ml/h. Group B patients received 10 ml of 0.15% bupivacaine with 5 microgram/ml of fentanyl followed by continuous epidural perfusion of 0.0625% bupivacaine with 2 microgram/ml of fentanyl at the same rate. Pain intensity was assessed on a visual analog scale, motor blockade on a Bromage scale, and level of sensory block at different moments. We also recorded total doses of local anesthetic employed during continuous epidural infusion, manner of final delivery, Apgar score, degree of maternal satisfaction and side effects. RESULTS: The demographic and delivery characteristics were similar in both groups. We found no statistically significant differences between the two groups for level of motor blockade, which was nil for 29 patients (96.66%) in group R and 28 patients (93.33%) in group B. No differences in degree of pain or level of sensory block (T8-T10 in both groups) were observed.The total doses of local anesthetic used were similar at 23.7 +/- 11.6 mg in group R and 16.5 +/- 7.3 mg in group B (non-significant difference). Nor did we find differences in manner of delivery, neonatal Apgar scores, degree of maternal satisfaction or side effects. CONCLUSION: Ropivacaine and bupivacaine are equally effective for epidural analgesia during labor at the doses used and they do not cause a relevant level of motor blockade.     

低浓度罗哌卡因和布比卡因分娩镇痛的临床研究

目的 对比低浓度罗哌卡因和布比卡因自控硬膜外分娩镇痛（ＰＣＥＡ）的效果。方法 ５２例单胎初产妇随机分为０．１％罗哌卡因－芬太尼组和０．０７５％布比卡因－芬太尼组。采取双盲法进行视觉模拟镇痛评分（ＶＡＳ）和下肢运动神经阻滞评分（ＭＢＳ）。记录产程时间、生产方式、胎儿心率（ＦＨＲ）及新生儿ＳｐＯ２。结果 两组产妇分娩镇痛效果良好且无显著性差别（Ｐ〉０．０５）。罗哌卡因组和布比卡因组中无运动神经阻滞者分     

Ambulatory labor epidural analgesia: bupivacaine versus ropivacaine

Dilute concentrations of bupivacaine combined with fentanyl have recently been used to initiate labor epidural analgesia in an attempt to balance adequate analgesia and minimal maternal motor blockade. Similar concentrations of ropivacaine have not been evaluated. This prospective, randomized, double-blinded study was designed to compare the efficacy of 20 mL of either 0.08% bupivacaine plus 2 microg/mL fentanyl or 0.08% ropivacaine plus 2 microg/mL fentanyl to initiate ambulatory labor epidural analgesia. Forty nulliparous women in early ( 0 but < 20 at 20 min. The time (mean +/- SD) to visual analog scale score = 0 was BF (n = 18): 12.0 +/- 4.5 min and RF (n = 19): 12.4 +/- 4.0 min (P > 0.05). Spontaneous micturition was observed in 65% (13 of 20) BF compared with 100% (20 of 20) RF (P < 0.01), and ambulation was demonstrated in 75% (15 of 20) BF compared with 100% (20 of 20) RF (P < 0.03). The incidence of forceps delivery was 35% (7 of 20) BF compared with 10% (2 of 20) RF (P < 0.04). The results of this study indicate that dilute ropivacaine combined with fentanyl effectively initiates epidural analgesia while concurrently preserving maternal ability to void and ambulate. Implications: As compared with a similar dilute concentration of bupivacaine, 20 mL of dilute (0.08%) ropivacaine combined with fentanyl (2 microg/mL) effectively initiates epidural analgesia in nulliparous women in early, established labor while preserving their ability to micturate and ambulate. Of importance, it appears that a true ambulatory epidural analgesic for women in labor is now possible.     

Efficacy of ropivacaine, bupivacaine, and levobupivacaine for labor epidural analgesia

STUDY OBJECTIVE: To compare analgesic efficacy and intensity of motor block with continuous infusions of ropivacaine, bupivacaine, and levobupivacaine in combination with fentanyl for labor epidural analgesia. DESIGN: Prospective, randomized, double-blinded study. SETTING: Labor and delivery suite at Magee Womens Hospital, Pittsburgh, PA. PATIENTS: 162 ASA physical status I and II, full-term, primiparous women. INTERVENTIONS: All patients received epidural labor analgesia. Epidural medication consisted of an initial bolus of 8 mL local anesthetic with fentanyl (100 microg) followed by an infusion at 12 mL/h of local anesthetic with 2 microg/mL fentanyl. Patients were allocated to one of three groups, as follows: group 1 received bolus and infusion of bupivacaine 0.125%, group 2 received bolus and infusion of levobupivacaine 0.125%, and group 3 received a bolus of ropivacaine 0.2% and infusion of ropivacaine 0.1%. MEASUREMENTS: Maternal vital signs, pain visual analog scale (VAS) score, sensory levels, and motor block (Bromage score) were recorded every hour. Duration of first and second stage of labor and mode of delivery were also recorded. RESULTS: There were no statistically significant differences in pain VAS or Bromage motor scores among the three groups of patients at any of the measured time intervals. The time to achieve T10 sensory level and patient comfort was shorter in the ropivacaine (9.35 +/- 4.96 min) and levobupivacaine (9.56 +/- 4.71 min) groups than the bupivacaine (11.89 +/- 7.76 min) group, although this difference did not reach a statistically significant level (P = 0.06). The second stage was significantly shorter in the bupivacaine group, lasting 81.27 +/- 63.3 min, compared with the ropivacaine group (121.69 +/- 86.5 min) and the levobupivacaine (115.5 +/- 83.6 minutes) group (P = 0.04). CONCLUSION: There are no significant differences in pain VAS and Bromage scores between 0.1% ropivacaine, 0.125% bupivacaine, and 0.1% levobupivacaine given for labor epidural analgesia.     

Parturient-controlled epidural analgesia during labour: bupivacaine vs. ropivacaine

In this randomised, controlled study, we compared the hourly dose requirement of ropivacaine 0.125% (group R, n = 16) with bupivacaine 0.125% (group B, n = 16) provided by demand-only (bolus 5 ml, lockout 10 min) parturient-controlled epidural analgesia during labour. The hourly dose requirement was comparable although group R had a lower successful to total demands ratio (p < 0.05). We also found that both groups were clinically indistinguishable in terms of pain relief and side-effects. No difference in maternal or fetal outcome was detected. We conclude that, at a concentration of 0.125%, ropivacaine and bupivacaine were equally effective when self-administered using this patient-controlled regimen.     

Epinephrine enhances analgesia produced by epidural bupivacaine during labor

Reports on the analgesic and hemodynamic effects of epinephrine added to bupivacaine for epidural use in obstetrics are conflicting. In this study, healthy parturients received in a random manner either 10 ml of 0.25% bupivacaine (n = 50) or 10 ml of 0.25% bupivacaine with 1:300,000 epinephrine (n = 50) epidurally. Epinephrine enhanced the analgesia produced by bupivacaine: onset was hastened (5.8 +/- 0.6 vs 8.7 +/- 0.8 min, mean +/- SEM, P less than 0.05), duration prolonged (123 +/- 7.0 vs 92 +/- 5.0 min, P less than 0.05), and the number of women requiring additional local anesthetic for analgesia decreased (9 vs 18, P less than 0.05) compared to the group receiving plain bupivacaine. The incidence of hypotension did not differ between groups. Maternal heart rate increased only after injection of the epinephrine-containing solution. The authors conclude that epinephrine 1:300,000 modestly but statistically significantly improves the analgesic efficacy of epidurally administered 0.25% bupivacaine during labor.     

Dose-response study of epidural ropivacaine for labor analgesia

BACKGROUND: Ropivacaine has been introduced for use in epidural analgesia in labor. However, there have been few formal dose-response studies of ropivacaine in this setting. METHODS: The authors performed a prospective, randomized, double-blind study examining the effectiveness of five different doses of ropivacaine (10, 20, 30, 40, and 50 mg) administered epidurally in a volume of 10 ml to establish analgesia in 66 parturients who were in active labor with cervical dilatation less than 4 cm. A dose was considered effective when the visual analog scale pain score decreased by 50% or more from baseline. RESULTS: A sigmoid dose-response curve and a probit log dose-response plot (linear regression coefficient, r = 0.84; coefficient of determination, r2 = 0.71) were obtained. The ED50 (median effective dose) obtained based on the maximum likelihood estimation was 18.4 mg (95% confidence interval, 13.4-25.4 mg). Time to onset of analgesia, duration of analgesia, time to two-segment regression of sensory block level, and incidence of motor block were not affected by the dosage of ropivacaine administered (P = 0.93, 0.12, 0.55, and 0.39, respectively). However, the upper level of sensory block was dose-related (P < 0.01). CONCLUSION: In a traditional dose-response study, the ED50 of ropivacaine required to initiate epidural analgesia in early labor was found to be 18.4 mg (95% confidence interval, 13.4-25.4 mg).     

A comparison between low-dose ropivacaine and bupivacaine at equianalgesic concentrations for epidural analgesia during the first stage of labor

The aim of this study was to evaluate the efficacy, onset and duration of analgesia of two equianalgesic epidural doses of ropivacaine and bupivacaine during the first stage of labor. The study included 190 healthy nulliparous parturients who presented spontaneous onset of labor and required epidural analgesia. They were divided randomly to receive epidural analgesia with an initial dose 0.10% ropivacaine or 0.0625% bupivacaine 20 mL both with the addition of 10 microg of sufentanil. There were no significant differences in onset time, quality of analgesia, maternal hypotension and ability to ambulate. Ropivacaine produced more prolonged analgesia then bupivacaine (89 vs 119 min;P<0.0003). The clinical value of this prolonged analgesia after the first dose needs further evaluation when a continuous infusion technique is used.     

0.15%罗哌卡因硬膜外给药用于分娩镇痛中爆发痛的治疗效果

目的比较不同浓度罗哌卡因单独或复合舒芬太尼硬膜外给药抑制分娩镇痛中爆发痛的临床效果。方法选择成功施行硬膜外分娩镇痛后,第一产程中出现爆发痛的初产妇60例,ASAⅠ或Ⅱ级,足月单胎,随机分为0.15%罗哌卡因的追加组(A组)和0.08%罗哌卡因复合舒芬太尼0.4μg/ml的追加组(B组),每组30例。记录产妇VAS评分、改良Bromage评分、追加次数、罗哌卡因、舒芬太尼用量及缩宫素使用例数、产程时间、分娩方式、不良反应等。结果与B组比较,A组爆发痛给予追加剂量20min后VAS评分明显降低,追加次数明显减少,舒芬太尼用量明显减少,皮肤瘙痒、尿潴留等不良反应发生率明显下降;两组改良Bromage评分均为0,缩宫素使用例数、产程时间、分娩方式差异无统计学意义。结论0.08%罗哌卡因复合舒芬太尼0.4μg/ml背景输注8ml/h的情况下,0.15%罗哌卡因抑制分娩镇痛后第一产程中出现的爆发痛的效果明显优于0.08%罗哌卡因复合舒芬太尼0.4μg/ml,且不良反应少。     

Relative analgesic potencies of ropivacaine and bupivacaine for epidural analgesia in labor: implications for therapeutic indexes

BACKGROUND: The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to assess the relative analgesic potencies of epidural bupivacaine and ropivacaine by determining their respective minimum local analgesic concentrations. METHODS: Seventy-three parturients at < or = 7 cm cervical dilation who requested epidural analgesia were allocated to one of two groups in this double-blinded, randomized, prospective study. After a lumbar epidural catheter was placed, 20 ml of the test solution was given, either ropivacaine (n = 34) or bupivacaine (n = 39). The concentration of local anesthetic was determined by the response of the previous patient in that group to a higher or lower concentration using up-down sequential allocation. Analgesic efficacy was assessed using 100-mm visual analog pain scores with < or = 10 mm within 30 min defined as effective. An effective result directed a 0.01% wt/vol decrement for the next patient. An ineffective result directed a 0.01% wt/vol increment. RESULTS: The minimum local analgesic concentration of ropivacaine was 0.111% wt/vol (95% confidence interval, 0.100-0.122), and the minimum local analgesic concentration of bupivacaine was 0.067% wt/vol (95% confidence interval, 0.052-0.082). Ropivacaine was significantly less potent than bupivacaine, with a potency ratio of 0.6 (95% confidence interval, 0.49-0.74). No difference in motor effects was observed. CONCLUSION: Ropivacaine was significantly less potent than bupivacaine for epidural analgesia in the first stage of labor.     

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.     

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

We previously found that the extent of an epidural motor block produced by 0.125% ropivacaine was clinically indistinguishable from 0.125% bupivacaine in laboring patients. By adding fentanyl to the 0. 125% ropivacaine and bupivacaine solutions in an attempt to reduce hourly local anesthetic requirements, we hypothesized that differences in motor block produced by the two drugs may become apparent. Fifty laboring women were randomized to receive either 0. 125% ropivacaine with fentanyl 2 microg/mL or an equivalent concentration of bupivacaine/fentanyl using patient-controlled epidural analgesia (PCEA) with settings of: 6-mL/hr basal rate, 5-mL bolus, 10-min lockout, 30-mL/h dose limit. Analgesia, local anesthetic use, motor block, patient satisfaction, and side effects were assessed until the time of delivery. No differences in verbal pain scores, local anesthetic use, patient satisfaction, or side effects between groups were observed; however, patients administered ropivacaine/fentanyl developed significantly less motor block than patients administered bupivacaine/fentanyl. Ropivacaine 0.125% with fentanyl 2 microg/mL produces similar labor analgesia with significantly less motor block than an equivalent concentration of bupivacaine/fentanyl. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the PCEA technique remains to be determined. Implications: By using a patient-controlled epidural analgesia technique, ropivacaine 0.125% with fentanyl 2 microg/mL produces similar analgesia with significantly less motor block than a similar concentration of bupivacaine with fentanyl during labor. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the patient-controlled epidural analgesia technique remains to be determined.     

产妇分娩时舒芬太尼或芬太尼混合罗哌卡因病人自控硬膜外镇痛的效应

目的比较产妇分娩时舒芬太尼或芬太尼混合罗哌卡因病人自控硬膜外镇痛(PCEA)的效应。方法无产科及硬膜外阻滞禁忌证的阴道分娩单胎初产妇120例,随机分为2组(n：60)：舒芬太尼混合罗哌卡因PCEA组(S组)和芬太尼混合罗哌卡因PCEA组(F组)。当产妇宫口开至3cm时,L_(2,3)间隙硬膜外穿刺置管,S组硬膜外注射0．15%罗哌卡因和0．5μg/ml舒芬太尼混合液试验剂量5 ml,随后追加上述混合液10 ml,30min后以0．1%哌卡因和0．5μg/ml舒芬太尼的混合液行PCEA；F组混合液中以2μg/ml芬太尼替代0．5μg/ml舒芬太尼,其他用药情况均与S组同。两组PCA剂量为6 ml,锁定时间为15 min。记录产妇视觉模拟疼痛评分(VAS)、下肢运动神经阻滞程度、生命体征、产程、分娩方式、不良反应及新生儿Apgar评分。结果两组镇痛期间VAS评分均降低,S组镇痛20～60 min VAS评分均低于F组。两组镇痛起效时间、达最高镇痛平面的时间、最高绝对平面、PCA实际按压次数、有效按压次数差异均无统计学意义。S组皮肤瘙痒的发生率高于F组,舒芬太尼、芬太尼用量分别为16±8、(70±28)μg,比率为1：4．4。两组产程和分娩方式构成比差异无统计学意义。结论产妇分娩时等效剂量的舒芬太尼或芬太尼混合罗哌卡因PCEA均可提供良好的镇痛效果。     

不同浓度芬太尼对硬膜外罗哌卡因分娩镇痛效应的影响

目的 观察不同浓度芬太尼对硬膜外罗哌卡因分娩镇痛效应的影响。方法 本研究为多中心、随机、双盲对照研究，选择要求分娩镇痛的初产妇128例，ASAⅠ或Ⅱ级，随机分为4组，FD组（n=33）：单纯罗哌卡因组；F1组（n=30）：罗哌卡因混合1μg/ml芬太尼组；F2组（n=33）：罗哌卡因混合2μg/ml芬太尼组；F3组（n=32）：罗哌卡因混合3μg/ml芬太尼组。所有产妇于L2．3硬膜外穿刺头向置管，注入15ml药液。各组初始罗哌卡因浓度为0．12％，其后每例产妇所用浓度按双盲、序贯法进行调整。以VAS评价产妇注药30min内镇痛效果，计算硬膜外罗哌卡因分娩镇痛的半数有效浓度（EC50），记录注药后30min产妇收缩压、心率及胎儿心率、运动阻滞程度及不良反应发生情况。结果 共有124例完成试验观察。各组硬膜外罗哌卡因分娩镇痛的EC50及其95％可信区间（95％CI）为：F0组：0．110％及0．1090％-0．1116％；F1组：0．089％及0．0877％-0．0911％；F2组：0．073％及0．0717％～0．0744％；F3组：0．060％及0．0560％～0．0634％，F1、F2、F3组EC50低于F0组（P〈0．01）。硬膜外注药后30min内，产妇心率、血压、胎儿心率均在正常范围，各组运动阻滞程度比较差异无统计学意义（P〉0．05）；与F0组比较，乃组皮肤瘙痒发生率升高（P〈0．05）。结论 硬膜外混合低浓度芬太尼（1-3μg/ml）能增强0．12％罗哌卡因分娩镇痛效果，推荐芬太尼的安全浓度范围为1～2μg/ml。     

Motor block during patient-controlled epidural analgesia with ropivacaine or ropivacaine/fentanyl after intrathecal bupivacaine for caesarean section

We compared patient-controlled epidural analgesia (PCEA) withropivacaine alone or combined with fentanyl in terms of analgesicefficacy, motor weakness and side-effects in patients who hadreceived spinal anaesthesia for elective Caesarean section.ASA I patients received combined spinal–epiduralanaesthesia and were randomly assigned, in a double-blind study,into two groups after operation: group R (n=23) received PCEAropivacaine 0.1%, bolus 5 mg, lockout 15 min, 3 mg h^–1background infusion, and group RF (n=24) received PCEA 0.1%ropivacaine/fentanyl 2 µg ml^–1 at identicalsettings. Pain and satisfaction on a 100 mm visual analoguescale (VAS) and side-effects were noted. Incidence of motorweakness (Bromage grade 1 or higher) was 48% (11/23) at8 h in group R compared with 13% (3/24) in group RF (P=0.025). Painscores on movement were lower in group RF at 8 and 12 hand at rest at 6 and 8 h (P<0.05 for each comparison).Analgesic consumption was less in RF (P=0.041), but there wasno difference in time to first request for supplementary analgesia.Patient satisfaction with postoperative analgesia (mean (SD))was higher in RF (79 (23) vs 57 (29) mm, P=0.045).Caution should be exercised using ropivacaine PCEA after spinalbupivacaine for Caesarean section, because its reputed motor-sparingproperty may be unreliable. Br J Anaesth 2000; 85: 468–70 ^* Corresponding author: University Department of Anaesthesia,Leicester General Hospital, Leicester LE5 4PW, UK     

罗哌卡因复合芬太尼用于产妇自控硬膜外分娩镇痛的可行性

目的评价罗哌卡因复合芬太尼用于产妇自控硬膜外镇痛的可行性.方法ASA I～Ⅱ级初产妇足月单胎90例随机分为3组.30例为对照组,60例分为2组镇痛组A组(PCEA-LP)0.2%罗哌卡因复合芬太尼2μg/ml负荷量10ml,当VAS≥20mm时,自控给药4ml/次,锁定时间为15min.B组(PCEA-LCP)相同药物负荷量10ml,半小时后背景量4ml/h,当VAS≥20mm给药4ml/次,锁定时间为15min,直到宫口开全停药.连续监测呼吸循环状况,评估镇痛效应和运动阻滞的程度,观察记录产程进展,采集静脉血测血浆儿茶酚胺浓度,观察不良反应及新生儿情况.结果新生儿评分,脐带静脉血血气分析,活跃期及第Ⅱ产程时间3组无显著差异.A、B两组间VAS疼痛评分,感觉阻滞,运动阻滞程度,NE,E浓度和剖宫产率无差别.对照组剖宫产率显著高于镇痛组(P＜0.01),第一产程末NE、E浓度显著高于镇痛组(P＜0.01).A组用药量、瘙痒发生率低及胎头吸引率均低于B组(P＜0.01).结论0.2%罗哌卡因复合芬太尼2μg/ml硬膜外自控镇痛安全有效,降低了剖宫产率,在相同的分娩镇痛水平PCEA-LP模式比PCEA-LCP模式用药更少,副作用发生率低.     

A double-blind comparison of 0.125% ropivacaine with sufentanil and 0.125% bupivacaine with sufentanil for epidural labor analgesia

BACKGROUND: This study intends to evaluate the benefits of the administration of intermittent bolus doses of ropivacaine (0.125%) compared with bupivacaine (0.125%) after addition of sufentanil for analgesia during labor. METHODS: One hundred thirty American Society of Anesthesiologists physical status 1 or 2 parturients were studied. The 90 initial patients were assigned randomly to receive 10 ml bupivacaine, 0.125%, plus 7.5 microg sufentanil (initial bupivacaine 0.125% group) or ropivacaine, 0.125%, plus 7.5 microg sufentanil (ropivacaine 0.125% group). Forty additional patients were recruited and received 0.125% bupivacaine plus 7.5 microg sufentanil (additional bupivacaine 0.125% group) or 0.100% bupivacaine plus 7.5 microg sufentanil (additional bupivacaine 0.100% group). The duration of analgesia, visual analogue scores for pain, motor blockade (using a six-point modified Bromage scale), patient satisfaction scores, nausea, pruritus, heart rate, and blood pressure were recorded. RESULTS: Bupivacaine 0.125% and ropivacaine 0.125% coadministered with sufentanil provided rapid and complete analgesia. Onset of analgesia occurred after +/-15 min and lasted +/-90 min. After the third epidural injection, patients in the ropivacaine group experienced significantly less severe motor blockade than patients in the initial bupivacaine 0.125% group. At this point, 93% of the patients in the ropivacaine group were free from motor impairment versus 66% in the bupivacaine group (P<0.05). Comparable levels of motor blockade were obtained in both additional groups. Patients' evaluation of their analgesia was worst in the bupivacaine 0.100% group. CONCLUSIONS: Ropivacaine 0.125% with sufentanil affords reliable analgesia with minimal motor blockade.     

A comparison of 0.0625% bupivacaine with fentanyl and 0.1% ropivacaine with fentanyl for continuous epidural labor analgesia

We compared the analgesic efficacy and the degree of motor block achieved with epidural infusion of 0.0625% bupivacaine (Group B) versus 0.1% ropivacaine (Group R), both with 0.0002% fentanyl (2 microg/mL) in laboring patients. A prospective, double-blinded study was performed in 98 ASA physical status I-II parturients who were divided randomly into two groups to receive either bupivacaine or ropivacaine after catheter location had been tested with an initial bolus of lidocaine and fentanyl. The infusion rate was 15 mL/h in every case. When pain was perceived, 5-mL boluses of the assigned epidural analgesic were administered every 10 min until analgesia was achieved. We recorded pain intensity, level of sensory block, degree of motor block, hemodynamic variables, secondary effects, mode of delivery, neonatal outcome, and patient satisfaction. There were no statistically significant differences in any of the factors analyzed. Highly effective analgesia was achieved in both groups with a small incidence of motor block. These findings suggest that bupivacaine may be more potent than ropivacaine. IMPLICATIONS: We compared different concentrations of epidural bupivacaine and ropivacaine thought to be equipotent. Both solutions were equally efficient in providing highly effective epidural analgesia for labor with minimal motor block. These findings suggest that bupivacaine may be more potent than ropivacaine.