Addition of epinephrine to epidural ropivacaine during labour--effects on onset and duration of action, efficacy, and systemic absorption of ropivacaine

Addition of epinephrine to epidural anaesthetic solutions may enhance efficacy and duration of analgesia. We postulated that addition of epinephrine 5 microg.mL(-1) to epidural ropivacaine would improve efficacy, decrease systemic absorption and reduce neonatal effects. Twenty-one multiparous women were studied. An initial dose of ropivacaine 30 mg followed by an infusion of ropivacaine 10 mg.h(-1) was given via a lumbar epidural catheter. According to random allocation, epinephrine 5 microg.mL(-1) was added to ropivacaine. Ropivacaine concentrations were measured in maternal venous plasma after one hour of infusion and in both umbilical venous and maternal plasma at delivery. Neonatal neurologic and adaptive capacity score (NACS) tests were performed at 2 and 24 h postpartum. All women delivered vaginally. The groups had similar ropivacaine dose requirements, epidural-delivery intervals and satisfaction scores. Bromage scores for motor block were greater in the epinephrine group (2; range: 1-3) than controls (1; range: 0-2). Mean plasma ropivacaine concentrations (+/-SD) were less in the epinephrine group (0.17 +/- 0.05 mg.L(-1), n = 10) than controls (0.31 +/- 0.14 mg.L(-1), n = 11; P < 0.05) after one h of infusion but not at delivery. UV ropivacaine concentrations and NACS scores were similar in the two groups. The addition of epinephrine to ropivacaine decreases maternal plasma concentrations after one h of epidural infusion but also increases motor block.     

Sensory and motor blockade during epidural analgesia with 1%, 0.75%, and 0.5% ropivacaine--a double-blind study

Levels of sensory (pinprick) and somatic motor blockade were measured in a double-blind study of 30 volunteers given single epidural injections of 1%, 0.75%, and 0.5% ropivacaine. Onset of analgesia was rapid with all concentrations (7-10 min). Maximal levels of analgesia were established 60 min after injection, with no significant differences in the maximal median cephalad spread. Duration of analgesia at the T-12 level and total duration were significantly longer with 1% and 0.75% than with 0.5% ropivacaine. Motor blockade was assessed by a quantitative method (measurements of isometric muscle force) and a qualitative method (modified Bromage scale). Onset of motor blockade measured by the quantitative method was significantly slower with 0.5% ropivacaine than with the higher concentrations. Maximal muscle weakness occurred 1-1.5 h after injection with all three concentrations. With increase in ropivacaine dose from 100 to 200 mg, the intensity and duration of motor blockade increased. Muscles involved in knee extension were blocked most, those of plantar flexion least. Recovery of motor function, assessed by the above-mentioned quantitative method, occurred simultaneously with the recovery of pinprick perception. Motor blockade registered by Bromage scale showed a slower onset for 0.5% ropivacaine than for the higher concentrations. Mean durations of grade 1 and 2 block were longest for the 1% solution. Motor blockade described by the Bromage scale showed only the first part of the regression phase. Full recovery of muscle strength (Bromage scale = 0) was attained 1.5-2.5 h earlier than assessed by the quantitative method. No adverse effects were registered.     

A comparison of intrathecal plain solutions containing ropivacaine 20 or 15 mg versus bupivacaine 10 mg

Ropivacaine, which blocks sensory nerve fibers more readily than motor fibers, is considered to be less potent than bupivacaine. Our hypothesis was that, when used in spinal anesthesia for day surgery, ropivacaine 15 and 20 mg would provide faster motor recovery than bupivacaine 10 mg. This prospective, randomized, double-blinded study included 90 ambulatory lower-extremity surgery patients who received 2 mL of ropivacaine 1%, ropivacaine 0.75%, or bupivacaine 0.5%. Motor block was tested with the Bromage scale, and sensory block was tested with pinprick. Ropivacaine 15 mg provided faster recovery of motor block (150 min) than did bupivacaine 10 mg (210 min; P = 0.005), but the median duration of sensory block at T10 (140 min) did not differ significantly from that with bupivacaine 10 mg (140 min). The median duration of sensory block at T10 was significantly longer with ropivacaine 20 mg (170 min) than with bupivacaine 10 mg (140 min; P = 0.005), but the median recovery from motor block (210 min) did not differ significantly. We conclude that the duration of sensory block of ropivacaine was two thirds and the duration of motor block was half when compared with bupivacaine, with calculations based on the duration-per-milligram of the local anesthetic.     

Factors affecting the spread and duration of epidural anesthesia with ropivacaine

BACKGROUND: Epidural anesthesia has an unpredictable extent and duration. Differences in the surface area of the lumbosacral dura, epidural fat volume, and epidural venous plexus velocity might explain the variability in the extent and duration of epidural anesthesia with ropivacaine. METHODS: Twenty-six healthy patients, aged 18-45 y, undergoing peripheral orthopedic surgery were enrolled. Dural surface area and posterior epidural fat volume were calculated from low thoracic, lumbar, and sacral axial magnetic resonance images obtained at 8-mm increments. Epidural venous plexus velocity at the L3-L4 disk level was derived from phase-contrast magnetic resonance images. The patients received 100 mg ropivacaine (1.0%) epidurally. The spread and duration of sensory anesthesia was assessed by pinprick, and that of motor block was assessed using a modified Bromage scale. Statistical correlation coefficients (rho) between magnetic resonance imaging and epidural anesthesia measurements were assessed by Spearman rank correlation. Stepwise multiple linear regression models were used to select important predictors of measures of epidural anesthesia. RESULTS: Dural surface area correlated with peak sensory block level (rho= -0.73, P = 0.0003) and onset time of caudal and cephalad block (rho = 0.62, P = 0.002; rho = -0.63, P = 0.002). Fat volume correlated with the regression to L5-S3 (rho = -0.44.44 to -0.54, P = 0.029 to 0.007). Epidural venous plexus velocity was significantly correlated with the regression to L3 (rho = -0.42, P = 0.038) and L4 (rho = -0.48, P = 0.017). Multiple regression analysis revealed that dural surface area was a significant predictive variable for the peak sensory block level (R = 0.61, P < 0.0001). CONCLUSIONS: These findings indicate that dural surface area influences the spread of epidural anesthesia with ropivacaine and posterior fat volume influences the duration of epidural anesthesia in healthy patients within a narrow age range. Epidural venous plexus velocity might also influence the duration of epidural anesthesia with ropivacaine.     

Intrathecal ropivacaine for total hip arthroplasty: double-blind comparative study with isobaric 7.5 mg ml(-1) and 10 mg ml(-1) solutions

This study was designed to evaluate the efficacy and safetyof two concentrations of intrathecal ropivacaine, 7.5 and 10mg ml^–1, in patients undergoing total hip arthroplasty.One hundred and four patients, ASA I–III, were randomizedto receive an intrathecal injection of one of two concentrationsof isobaric ropivacaine. Group 1 (n=51) received 2.5 ml of 7.5mg ml^–1 ropivacaine (18.75 mg). Group 2 (n=53) received2.5 ml of 10 mg ml^–1 ropivacaine (25 mg). The onset andoffset of sensory block at dermatome level T10, maximum upperand lower spread of sensory block and the onset, intensity andduration of motor block were recorded, as were safety data.Onset of motor and sensory block was rapid with no significantdifferences between the two groups. The median time of onsetof sensory block at the T10 dermatome was 2 min (range 1–25min) in Group 1 and 2 min (range 1–21 min) in Group 2.The median duration of sensory block at the T10 dermatome was3.0 h (range 0.5–4.2 h) in Group 1 and 3.4 h (1.1–5.9h) in Group 2 (P=0.002). The median duration of complete motorblock was significantly prolonged (P<0.05) in Group 2 comparedwith Group 1 (1.9 vs 1.2 h, respectively). Anaesthetic conditionswere excellent in all but one patient. Intrathecal ropivacaine,in doses of 18.75 and 25 mg, was well tolerated and providedeffective anaesthesia for total hip arthroplasty. Br J Anaesth 2001; 87: 743–7     

Clinical effects and pharmacokinetics of ropivacaine and bupivacaine for epidural analgesia during labor

OBJECTIVE: To compare the analgesic efficacy, pharmacokinetics and histamine release of ropivacaine and bupivacaine with fentanyl in continuous epidural perfusion during labor and childbirth. MATERIAL AND METHODS: Prospective study of 40 women at full-term pregnancy who requested epidural analgesia. The patients were randomly assigned to 2 groups of 20: group R received an initial bolus dose of 10 mL of 0.25% ropivacaine and group B received 0.25% bupivacaine, followed in both groups by epidural infusion of the assigned drugs at a concentration of 0.125% plus 0.30 mg of fentanyl at a rate of 5 mL/h through a patient-controlled analgesia device that allowed additional bolus doses. The studied variables were age, weight, height, sensory and motor block, mean blood pressure and maternal-fetal heart rates, number of bolus doses, total local anesthetic administered, duration and type of delivery, oxytocin increase, Apgar at 1 and 5 minutes, plasma levels of local anesthetic (30 minutes after the initial dose, at the end of dilation, in the umbilical vein, and 30 minutes after switching off the perfusion pump), time to clearance, elimination half-life, and a test of histamine release by radioimmunoassay. RESULTS: No significant differences were observed in the course of labor or in Apgar scores. The plasma concentrations of ropivacaine were higher than those of bupivacaine (p<0.03). Clearance of both drugs was similar. The elimination half-life of ropivacaine was significantly less than that of bupivacaine (5.2 +/- 0.7 h vs. 10.8 +/- 1.06 h). CONCLUSIONS: Analgesia was equally effective in both groups, without adverse maternal-fetal effects, with spontaneous micturition and absence of motor blockade in both groups. The plasma concentrations were higher with ropivacaine but were not toxic.     

Comparison of ropivacaine and lidocaine for intravenous regional anesthesia in volunteers: a preliminary study on anesthetic efficacy and blood level.

BACKGROUND: Ropivacaine may be useful for intravenous regional anesthesia, but its anesthetic effectiveness and toxicity have not been evaluated. METHODS: Two doses of ropivacaine (1.2 and 1.8 mg/kg) and one dose of lidocaine (3 mg/kg) were compared for intravenous regional anesthesia in 15 volunteers. An arm tourniquet was inflated for 30 min after injection and then deflated in two cycles. Sensory block was measured by response to touch, cold, pinprick, and transcutaneous electric stimulation, and motor function was measured by hand grip strength and muscle power. Median, ulnar, radial, and musculocutaneous nerve functions were tested before local anesthetic injection and then at 5-min intervals until blocks resolved. The plasma ropivacaine and lidocaine concentrations were determined from arterial and venous blood samples drawn from the unanesthetized arm. RESULTS: Sensory and motor blocks were complete within 25 min and 30 min, respectively, in all three treatment groups. However, recovery of sensory and motor block after tourniquet release was slowest in the high-dose ropivacaine group. Anesthesia to pinprick and transcutaneous electric stimulation was sustained in all the volunteers in the high-dose ropivacaine group for 55 min and 85 min, respectively, whereas complete recovery was observed in the lidocaine group (P = 0.008) and partial recovery in the low-dose ropivacaine group (P < 0.05) during the same period. Motor block also was sustained in the high-dose ropivacaine group for 70 min, which was significantly longer than in the lidocaine group (P < 0.05). All volunteers (five of five) given lidocaine and one volunteer given high-dose ropivacaine reported light-headedness and hearing disturbance during tourniquet release when the arterial plasma lidocaine and ropivacaine concentrations were 4.7+/-2.1 microg/ml (mean) and 2.7 micro/ml, respectively. CONCLUSION: Compared with lidocaine, intravenous regional anesthesia with ropivacaine appears to be comparable but has longer-lasting residual anesthesia.     

Comparison of Ropivacaine and Lidocaine for Intravenous Regional Anesthesia in Volunteers: A Preliminary Study on Anesthetic Efficacy and Blood Level

Background: Ropivacaine may be useful for intravenous regional anesthesia, but its anesthetic effectiveness and toxicity have not been evaluated.

Methods: Two doses of ropivacaine (1.2 and 1.8 mg/kg) and one dose of lidocaine (3 mg/kg) were compared for intravenous regional anesthesia in 15 volunteers. An arm tourniquet was inflated for 30 min after injection and then deflated in two cycles. Sensory block was measured by response to touch, cold, pinprick, and transcutaneous electric stimulation, and motor function was measured by hand grip strength and muscle power. Median, ulnar, radial, and musculocutaneous nerve functions were tested before local anesthetic injection and then at 5-min intervals until blocks resolved. The plasma ropivacaine and lidocaine concentrations were determined from arterial and venous blood samples drawn from the unanesthetized arm.

Results: Sensory and motor blocks were complete within 25 min and 30 min, respectively, in all three treatment groups. However, recovery of sensory and motor block after tourniquet release was slowest in the high-dose ropivacaine group. Anesthesia to pinprick and transcutaneous electric stimulation was sustained in all the volunteers in the high-dose ropivacaine group for 55 min and 85 min, respectively, whereas complete recovery was observed in the lidocaine group (P = 0.008) and partial recovery in the low-dose ropivacaine group (P < 0.05) during the same period. Motor block also was sustained in the high-dose ropivacaine group for 70 min, which was significantly longer than in the lidocaine group (P < 0.05). All volunteers (five of five) given lidocaine and one volunteer given high-dose ropivacaine reported light-headedness and hearing disturbance during tourniquet release when the arterial plasma lidocaine and ropivacaine concentrations were 4.7 +/- 2.1 [micro sign]g/ml (mean) and 2.7 [micro sign]/ml, respectively.     

A comparison of epidural ropivacaine 0.75% and bupivacaine 0.5% with fentanyl for elective caesarean section

BACKGROUND: Early studies suggested that ropivacaine had clinical advantages over bupivacaine with respect to cardiotoxicity and motor block, and that it was suitable for epidural caesarean section. This study was set up to compare epidural 0.75% ropivacaine with a popular bupivacaine/fentanyl mixture for elective caesarean section. METHODS: Eighty women having elective caesarean section under epidural anaesthesia were randomly allocated to receive 20 mL of either 0.75% ropivacaine or 0.5% bupivacaine plus fentanyl 100 microg. Supplementation with 2% plain lidocaine was used where necessary. Times were recorded for onset of sensory block, density and duration of motor block, and the need for supplementation. RESULTS: There was no difference between the groups in the time (mean [SD]) to achieve sensory blockade to cold to T4 (ropivacaine 15.8 [5.6] min, bupivacaine/fentanyl 18.7 [9.1] min, P=0.13) or to S1 (ropivacaine 18.3 [4.6] min, bupivacaine/fentanyl 17.4 [7.6] min, P=0.59), or in the need for supplementation. However, ropivacaine produced a motor block that was denser (median Bromage score ropivacaine 3, bupivacaine/fentanyl 1.5, P=0.0041), and of longer duration (ropivacaine 237 [84] min, bupivacaine/fentanyl 144 [76] min, P<0.0001). CONCLUSIONS: This study suggests that epidural 0.75% ropivacaine without opioid may be used as an alternative to bupivacaine 0.5% with fentanyl for elective caesarean section, but it does not induce anaesthesia any faster and may result in a denser, more prolonged, motor block.     

老年患者硬膜外注射罗哌卡因的药效动力学和药代动力学

目的 评价老年患者硬膜外注射罗哌卡因的药效动力学和药代动力学.方法 20例择期行疝修补术的老年患者为老年组,年龄65～84岁,体重52～75 kg;20例择期行疝修补术的成年患者为青年组,年龄20～加岁,体重49～77kg.于k2,3椎间隙行硬膜外穿刺,头端置管3～5 cm,于15min内注射0.5%罗哌卡因1.5 mg/kg.评价感觉阻滞程度,于给药后30 min评价运动阻滞程度,并分别于硬膜外给药前、给药后5、10、20、30、45、60、75、90、120、150 min时抽取足背动脉血样3 ml,采用高效液相色谱法测定血浆罗哌卡因浓度,计算罗哌卡因的药代动力学参数.结果 与青年组比较,老年组罗哌卡因的起效时间缩短,感觉阻滞平面固定时间及感觉阻滞消退时间延长,最高感觉阻滞平面及运动阻滞程度升高(P<0,05).两组罗哌卡因的血药浓度一时间曲线符合二室开放模型,并按一级动力学进行消除.与青年组比较,老年组罗哌卡因的浅室分布半衰期、深室分布半衰期、药峰时间、AUC0→150min、AUC0→Inf差异无统计学意义(P>0.05),罗哌卡因的消除半衰期延长,药峰浓度升高,清除率和表观分布容积减小(P<0.05).结论 老年患者罗哌卡因的血药浓度-时间曲线均符合二室开放模型,与成年患者比较,老年患者硬膜外注射罗哌卡因的总吸收无变化,清除率和表观分布容积减小,药峰浓度升高,消除半衰期延长,感觉阻滞平面和运动阻滞程度升高,感觉阻滞时间延长.     

Factors Affecting the Spread and Duration of Epidural Anesthesia with Ropivacaine

Background: Epidural anesthesia has an unpredictable extent and duration. Differences in the surface area of the lumbosacral dura, epidural fat volume, and epidural venous plexus velocity might explain the variability in the extent and duration of epidural anesthesia with ropivacaine.

Methods: Twenty-six healthy patients, aged 18-45 y, undergoing peripheral orthopedic surgery were enrolled. Dural surface area and posterior epidural fat volume were calculated from low thoracic, lumbar, and sacral axial magnetic resonance images obtained at 8-mm increments. Epidural venous plexus velocity at the L3-L4 disk level was derived from phase-contrast magnetic resonance images. The patients received 100 mg ropivacaine (1.0%) epidurally. The spread and duration of sensory anesthesia was assessed by pinprick, and that of motor block was assessed using a modified Bromage scale. Statistical correlation coefficients ([rho]) between magnetic resonance imaging and epidural anesthesia measurements were assessed by Spearman rank correlation. Stepwise multiple linear regression models were used to select important predictors of measures of epidural anesthesia.

Results: Dural surface area correlated with peak sensory block level ([rho] = -0.73, P = 0.0003) and onset time of caudal and cephalad block ([rho] = 0.62, P = 0.002; [rho] = -0.63, P = 0.002). Fat volume correlated with the regression to L5-S3 ([rho] = -0.44 to -0.54, P = 0.029 to 0.007). Epidural venous plexus velocity was significantly correlated with the regression to L3 ([rho] = -0.42, P = 0.038) and L4 ([rho] = -0.48, P = 0.017). Multiple regression analysis revealed that dural surface area was a significant predictive variable for the peak sensory block level (R2 = 0.61, P < 0.0001).     

Pharmacokinetics of three doses of epidural ropivacaine during hysterectomy and comparison with bupivacaine

Purpose

Ropivacaine is a new long-acting aminoamide local anaesthetic, structurally related to bupivacaine. The clinical efficacy of 125 mg, 187.5 mg and 250 mg ropivacaine have been reported and compared with 125 mg bupiva-caine for epidural analgesia during hysterectomy. In the pharmacokinetic part of this study the objectives were to I) determine the dose proportionality in the pharmacokinetics of epidural ropivacaine, and 2) compare the pharmacokinetics of 125 mg ropivacaine and 125 mg bupivacaine.

Methods

In a randomized, double-blind controlled study, patients received one of four treatment regimens with ropivacaine (125, 187.5 or 250 mg) or bupivacaine ( 125 mg) as a 25 ml epidural bolus administered over three minutes. Peripheral venous blood samples were collected over 24 hr for ropivacaine or bupivacaine quantification using gas chromatography with nitrogen sensitive detection. Pharmacokinetic variables were derived from plasma concentration-time curve data.

Results

Fifty two women entered the study Demographic characteristics were similar among groups. Six patients were excluded due to inadequate sensory block or an insufficient number of plasma samples. The peak plasma concentration (C_max) of ropivacaine and the total area under the plasma concentration-time curve (AUC) increased proportionally with the dose. Apparent plasma clearance (CL) and the terminal half-life (t_1/2) were similar in the three ropivacaine groups. When compared with the 125 mg ropivacaine group, the bupivacaine group had a longer terminal half life (P < 0.05).

Conclusions

Epidural ropivacaine displays dose-proportional pharmacokinetic behaviour for doses of 125 mg to 250 mg. Ropivacaine has a shorter terminal half-life than bupivacaine.     

Comparison of ropivacaine and bupivacaine for intrathecal anesthesia during outpatient arthroscopic surgery

STUDY OBJECTIVE: To compare the effects of intrathecal ropivacaine with bupivacaine in a dose ratio of 2:1 for outpatient arthroscopic knee surgery. DESIGN: Randomized, single-blinded study. SETTING: University-affiliated hospital. PATIENTS: 90 patients scheduled for outpatient arthroscopic knee surgery. INTERVENTIONS: Patients were randomized and assigned in single-blinded fashion to receive a 3-mL solution of either 15 mg of isobaric ropivacaine (group R; n = 45) or 7.5 mg of isobaric bupivacaine (group B; n = 45) through a 27-gauge Quincke spinal needle at the L(3) to L(4) interspace, while placed in the lateral decubitus position. MEASUREMENTS: Onset and offset times for sensory and motor block; highest level of sensory block; duration of the sensory and motor block; first ambulation, urination, and discharge time; mean arterial pressure; and heart rate were all recorded. MAIN RESULTS: Onset time for sensory block (mean +/- SD) to L1 and time until sensory block regressed to L2 were shorter in group R. Complete motor block occurred in 40 patients with ropivacaine and 45 patients with bupivacaine. First ambulation and first urination and discharge times were similar between the two groups. Cephalad spread of sensory block was higher with ropivacaine (P < 0.05). The median (range) upper sensory level obtained with bupivacaine was T11 (T6-L1) and T8 (T6-T10) with ropivacaine. Hemodynamic changes were similar between the groups (P > 0.05). CONCLUSION: Isobaric ropivacaine 15 mg provided a higher sensory block level and shorter sensorial onset and offset times than did 7.5 mg of isobaric bupivacaine.     

Randomized double-blind comparison of ropivacaine-fentanyl and bupivacaine-fentanyl for spinal anaesthesia for urological surgery

BACKGROUND: Early studies have suggested that ropivacaine causes less motor block than bupivacaine, which might be advantageous in spinal anaesthesia for short procedures. The aim of this study was to compare plain ropivacaine 10 mg and plain bupivacaine 10 mg, both with fentanyl 15 microg, for spinal anaesthesia in urological surgery. Methods: This was a prospective randomized double-blind study. After written informed consent had been obtained, 34 ASA I-III patients scheduled for urological surgery were randomly assigned to receive intrathecal injection of either plain ropivacaine 10 mg with fentanyl 15 microg (ropivacaine group) or plain bupivacaine 10 mg with fentanyl 15 microg (bupivacaine group) using a combined spinal-epidural technique. RESULTS: All patients achieved sensory block to the T10 dermatome or higher at 15 min after intrathecal injection. One patient in the ropivacaine group was excluded because of unexpectedly prolonged surgery. The primary outcome, the duration of motor block, was shorter in the ropivacaine group (median, 126 min; interquartile range, 93-162 min) compared with the bupivacaine group (median, 189 min; interquartile range, 157-234 min; difference between medians, 71 min; 95% confidence interval, 28-109 min; P = 0.003). The duration of complete motor block was also shorter in the ropivacaine group compared with the bupivacaine group. There was no difference in the onset time of motor block. The characteristics of sensory block and the haemodynamic changes were similar between the groups. CONCLUSION: Plain ropivacaine 10 mg plus fentanyl 15 microg provided similar sensory anaesthesia, but with a shorter duration of motor block, compared with plain bupivacaine 10 mg plus fentanyl 15 microg when used for spinal anaesthesia in urological surgery.     

Combination of hyperbaric lidocaine and ropivacaine in spinal anaesthesia for day surgery

BACKGROUND AND OBJECTIVE: Motor function recovers rapidly but the extended duration of sensory block after spinal anaesthesia with hyperbaric ropivacaine may delay patients' ambulation after surgery. We tested whether compensating a reduction of the ropivacaine dose with a small dose of lidocaine would be adequate for surgery and shorten recovery from spinal anaesthesia. METHODS: Fifty-six consecutive outpatients, who were scheduled for lower extremity surgery under spinal anaesthesia, were randomized into two groups to receive either a hyperbaric solution of lidocaine 20 mg and ropivacaine 5 mg (Group LR) or hyperbaric ropivacaine 10 mg (Group R). Sensory block was tested with pinprick and motor block on the Bromage scale at 5-min intervals until 30 min, then at 15-min intervals until 90 min, and thereafter at 30-min intervals until full bilateral recovery. Blinded interviews were performed on the first and seventh postoperative day. RESULTS: The groups did not differ significantly regarding success of sensory block reaching T10 dermatome on the operative side, 24 (86%) in Group LR and 23 (82%) in Group R, median (range) onset time 5 (5-20) vs. 10 (5-25) min or median duration of T10 sensory block 68 (5-115) vs. 50 (20-115) min, respectively. Two patients in each group required general anaesthesia. Recovery did not differ between the groups, median time of full motor recovery was 75 min in both groups, sensory recovery of S2 2.5 h vs. 2.8 h, first voluntary micturition 4.2 (2.2-6.1) vs. 4.5 (2.4-6.6) h in the LR vs. R Group, respectively. Transient neurological symptoms did not appear. CONCLUSION: It is concluded that spinal anaesthesia with hyperbaric lidocaine 20 mg+ropivacaine 5 mg and hyperbaric ropivacaine 10 mg was quite similar regarding frequency, onset, duration of T10 dermatome sensory block and recovery. The patients would have been ready for discharge after voluntary micturition, 4.2-4.5 h from the subarachnoid injection of local anaesthetics.     

The effect of the addition of epinephrine on early systemic absorption of epidural ropivacaine in humans

The addition of epinephrine to ropivacaine has not been recommended because ropivacaine has intrinsic vasoconstrictor properties. However, few pharmacokinetic data are available on the addition of epinephrine to epidural ropivacaine in humans. In this prospective, double-blinded study, we randomized patients having elective abdominal hysterectomy to receive epidural ropivacaine 1.5 mg/kg, diluted in 15 mL, either with (epinephrine group, n = 12) or without (plain group, n = 12) epinephrine 5 microg/mL and then measured arterial and venous plasma concentrations of ropivacaine at intervals up to 180 min. We found that arterial and venous plasma ropivacaine concentrations were smaller in the epinephrine group compared with the plain group in the first 60 min after the drug administration (P < 0.01). Mean (+/- SD) maximum total plasma ropivacaine concentration was smaller in the epinephrine group (arterial, 0.92 +/- 0.32 microg/mL; venous, 0.82 +/- 0.33 microg/mL) compared with the plain group (1.31 +/- 0.39 microg/mL and 1.31 +/- 0.50 microg/mL, respectively; P = 0.01). Time to maximum total plasma ropivacaine concentration was not significantly different between groups (mean +/- SD; arterial, 16 +/- 2 min; venous, 23 +/- 2 min in the epinephrine group versus 9 +/- 2 min and 12 +/- 3 min, respectively, in the plain group; P = 0.08). Arterial plasma ropivacaine concentrations were larger than venous concentrations during the first hour (P < 0.01); the arterio-venous difference decreased exponentially, and the rate and magnitude of this decrease was unaffected by epinephrine. We conclude that the addition of epinephrine 5 microg/mL to ropivacaine reduced the early systemic plasma concentrations of ropivacaine after epidural injection and may be useful for decreasing the risk of toxicity from systemic absorption of epidural ropivacaine. IMPLICATIONS: The addition of epinephrine 5 microg/mL to epidural ropivacaine reduced the systemic arterial and venous plasma concentrations of ropivacaine in the first hour and the maximum plasma concentration of ropivacaine. Epinephrine may be a useful additive for reducing the risk of systemic toxicity when large doses of ropivacaine are given epidurally.     

Tramadol does not prolong the effect of ropivacaine 7.5 mg/ml for axillary brachial plexus block

BACKGROUND: The aim of this prospective, randomized, double-blind study was to evaluate the effect of the addition of tramadol to ropivacaine on the onset and duration of sensory and motor block, and duration of analgesia, for axillary brachial plexus block. METHODS: After institutional approval and informed consent had been obtained, 45 patients scheduled for forearm or hand surgery under axillary brachial plexus block were randomly allocated into two groups. The ropivacaine group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml of isotonic sodium chloride solution, and the tramadol group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml (100 mg) of tramadol. The onset and duration of sensory and motor block in the distribution of the musculocutaneous, radial, median and ulnar nerves, the duration of analgesia, the time to first pain medication, hemodynamics and side-effects were recorded. RESULTS: The addition of tramadol did not improve the speed of onset or increase the duration of sensory and motor block. The durations of analgesia were 631 +/- 33 min and 633 +/- 37 min (mean +/- standard deviation) in the ropivacaine and tramadol groups, respectively (P > 0.05). Hemodynamic parameters and side-effects did not differ between the groups. CONCLUSION: The addition of 100 mg of tramadol to 7.5 mg/ml of ropivacaine, for axillary brachial plexus block, does not prolong the duration of motor and sensory block and analgesia.     

Comparative motor-blocking effects of bupivacaine and ropivacaine, a new amino amide local anesthetic, in the rat and dog

Ropivacaine (S-(-)-1-propyl-2',6'-pipecoloxylidide) is a new local anesthetic that is structurally related to mepivacaine and bupivacaine. The comparative effects of ropivacaine and bupivacaine on motor function were assessed in the laboratory rat and dog. (It was not possible to accurately evaluate sensory blockade in these models.) Several concentrations of both agents were injected in the region of the sciatic nerve of the rat and into the lumbar epidural or subarachoid space in the dog. Epidural blockade was also performed utilizing solutions of ropivacaine and bupivacaine which contained epinephrine (1:200,000). The rat sciatic block studies indicate that at concentrations of 0.5 and 0.75%, ropivacaine had a slightly shorter time of onset and duration of motor blockade than did bupivacaine. In the epidural and spinal studies in the dog, ropivacaine was less potent and had a shorter duration of motor blockade than did bupivacaine at equal drug concentrations. A 1.0% solution of ropivacaine produced epidural motor blockade similar in onset and duration to that achieved with a 0.75% solution of bupivacaine. Epinephrine did not significantly prolong the duration of motor blockade of either agent after epidural administration.     

Epidural levobupivacaine 0.1% or ropivacaine 0.1% combined with morphine provides comparable analgesia after abdominal surgery

Ropivacaine appears attractive for epidural analgesia because it produces less motor block than racemic bupivacaine. The potential benefits of levobupivacaine with regard to motor blockade require further investigations. In this study, we compared the efficacy, dose requirements, side effects, and motor block observed with epidural levobupivacaine and ropivacaine when given in combination with small-dose morphine for 60 h after major abdominal surgery. Postoperatively, 50 patients were randomly allocated, in a double-blinded manner, to patient-controlled epidural analgesia with the same settings and without basal infusion, using 0.1% levobupivacaine or 0.1% ropivacaine. Both were combined with an epidural infusion of 0.1 mg/h morphine. Pain scores, side effects, motor block, and local anesthetic consumption were measured for 60 h. Pain scores measured on a 100-mm visual analog scale were approximately 20 mm at rest and 40 mm during mobilization in both groups. Bromage scores were 1 for all patients after the fourth postoperative hour. Consumption of levobupivacaine and ropivacaine were similar: 344 +/- 178 mg levobupivacaine versus 347 +/- 199 mg ropivacaine 48 h postoperatively. On postoperative day 2, 19 patients in the ropivacaine group versus 12 in the levobupivacaine group were able to ambulate (P < 0.05). No difference was noted concerning incidence of side effects. We conclude that when used as patient-controlled epidural analgesia and combined with small-dose epidural morphine, 0.1% levobupivacaine and 0.1% ropivacaine produce comparable postoperative analgesia with a similar incidence of side effects. IMPLICATIONS: Small concentrations (0.1%) of epidural levobupivacaine and ropivacaine combined with morphine (0.1 mg/h) produce comparable analgesia and have similar side effects for similar dose requirements.     

A prospective, randomized, double-blind comparison of epidural levobupivacaine 0.5% with epidural ropivacaine 0.75% for lower limb procedures

BACKGROUND AND OBJECTIVE: This prospective, randomized, observer-blinded study compared onset time and duration of epidural anaesthesia produced by with levobupivacaine and ropivacaine for lower limb surgery. METHODS: ASA I-III adult patients undergoing elective lower limb procedures were randomized to receive epidural levobupivacaine 0.5% 15 mL (n = 30) or epidural ropivacaine 0.75% 15 mL (n = 35). A blinded observer evaluated onset time and regression of motor and sensory block, and intraoperative needs for fentanyl supplementation (0.1 mg intravenously). RESULTS: With levobupivacaine, onset time was 29 +/- 24 min, with ropivacaine it was 25 +/- 22 min (P = 0.41). Complete resolution of motor block required 105 +/- 63 min with levobupivacaine and 95 +/- 48 min with ropivacaine (P = 0.86). The time for regression of sensory block to T12 was 185 +/- 77 min with levobupivacaine and 201 +/- 75 min with ropivacaine (P = 0.46). Analgesic supplementation was required in one patient receiving levobupivacaine (3.5%) and in two patients receiving ropivacaine (5.7%) (P = 0.99). CONCLUSIONS: In adults undergoing lower limb surgery, levobupivacaine 0.5% 15 mL produces an epidural block with the same clinical profile as ropivacaine 0.75% 15 mL.