Caudal 0.2% ropivacaine is less effective during surgery than 0.2% levobupivacaine and 0.2% bupivacaine: a double-blind, randomized, controlled trial

BACKGROUND: We hypothesized that without the analgesic effects of volatile anesthetics, caudal 0.20% ropivacaine would be less effective during surgical stimulation than 0.20% bupivacaine or 0.20% levobupivacaine. This trial was designed to examine whether the combination of a caudal block with 0.20% ropivacaine and i.v. anesthesia resulted in reduced analgesic efficacy during surgery compared with caudal 0.20% levobupivacaine or 0.20% bupivacaine in children. METHODS: Ninety ASA I-II children between 1 and 7 years old, scheduled for inguinal hernia repair or orchidopexy under propofol anesthesia were randomized to receive a caudal block with 1 ml x kg(-1) of 0.2% bupivacaine, 0.2% ropivacaine or 0.2% levobupivacaine. The primary outcome measure of the study was the clinical efficacy of the caudal block during surgery. Secondary outcome measures were postoperative pain relief and residual motor blockade. RESULTS: Four children were excluded and 86 were analyzed. The proportion of children with effective caudal block during surgery was significantly higher in children receiving levobupivacaine (26/28) or bupivacaine (27/29) compared with patients receiving ropivacaine (21/29) (P = 0.03). There were no significant differences among groups in the analgesic onset time (P = 0.1), incidence of residual motor blockade (P = 0.4), number of patients requiring analgesia after operation or in the time from caudal injection to the first administration of analgesic medication (P = 0.3). CONCLUSIONS: Combined with propofol anesthesia, 0.2% levobupivacaine and 0.2% bupivacaine are more effective than 0.2% ropivacaine for caudal use in children undergoing inguinal hernia repair or orchidopexy.     

Levobupivacaine 0.25% compared with ropivacaine 0.25% by the caudal route in children

BACKGROUND AND OBJECTIVE: Levobupivacaine is the most recently introduced local anaesthetic into clinical practice. In a randomized double-blinded study, the onset, intraoperative tolerance, postoperative analgesic effect, motor blockade and any adverse reactions produced by levobupivacaine were compared with ropivacaine. METHODS: Sixty children, ASA I-II, 2-6 yr old, undergoing elective minor surgery, received a single caudal injection of 1 mL kg(-1) of either levobupivacaine 0.25% or ropivacaine 0.25%. Caudal blocks were performed after induction of inhalation general anaesthesia using sevoflurane; anaesthesia was maintained via a laryngeal mask airway using a mixture of sevoflurane, oxygen and air. RESULTS: Onset time, intraoperative tolerance, postoperative analgesic effect and motor blockade were comparable between the two groups. The mean onset of the block was 8.2 +/- 2.2 min for levobupivacaine and 8.5 +/- 3.0 min for ropivacaine (P = 0.66). Additional analgesics during operation were not required in any of the children. No significant difference was found for mean time to requirement of additional analgesia with rectal acetaminophen (paracetamol) (302 +/- 29 min for the levobupivacaine group and 230 +/- 38 min for the ropivacaine group (P = 0.32)). During the first 4 h after placement of caudal block, the pain assessment score (according to the Children Hospital Eastern Ontario Pain Scale) was comparable for the two groups. No motor block was observed in any group on awakening, nor during the observation period. CONCLUSIONS: We conclude that levobupivacaine 0.25% 1 mL kg(-1) provides caudal block of comparable onset and duration, as produced by the same volume and concentration of ropivacaine.     

Ropivacaine 0.25% compared with bupivacaine 0.25% by the caudal route.

We compared in a randomized double-blind study, the postoperative analgesia and degree of motor block produced by the new local anaesthetic ropivacaine, with bupivacaine, for caudal anaesthesia in children. Eighty children, 2-5-years-old, ASA I, received one of two local anaesthetics; either ropivacaine 0.25% (1.0 ml x kg(-1)) or bupivacaine 0.25% (1.0 ml x kg(-1)). They were sedated with a continuous infusion of propofol (200 microg x kg(-1) min(-1). The lungs were ventilated with a mixture of 50% nitrous oxide with oxygen. 60 min after local anaesthetic injection, and every 60 min, the extent of the motor block in the recovery room was scored as 1-3, according to a modified Bromage scale. Adverse events and the time to the first analgesic requirement were reported. Patients in the two groups did not differ with respect to age, weight and height. There were no differences in heart rate and arterial pressure between the two groups(P>0.05). No adverse events were observed. The ropivacaine group showed a shorter duration of motor block than the bupivacaine group (P<0.05). The first postoperative analgesic requirement was a mean (sd) of 5 h+/-4.32 after the operation in the ropivacaine group and 5 h+/-3.81 for the bupivacaine group. These findings suggest that caudal anaesthesia with ropivacaine 0.25% in paediatric patients can be effective, with less motor blockade in the postoperative period.     

Comparison of the effects of intrathecal ropivacaine, levobupivacaine, and bupivacaine for Caesarean section

Background. This study aimed to detect if intrathecal (i.t.)ropivacaine and levobupivacaine provided anaesthesia (satisfactoryanalgesia and muscular relaxation) and postoperative analgesiaof similar quality to bupivacaine in patients undergoing Caesareansection. Methods. Ninety parturients were enrolled. A combined spinal-epiduraltechnique was used. Patients were randomly assigned to receiveone of the following isobaric i.t. solutions: bupivacaine 8mg (n=30), levobupivacaine 8 mg (n=30), or ropivacaine 12 mg(n=30), all combined with sufentanil 2.5 µg. An i.t. solutionwas considered effective if an upper sensory level to pinprickof T4 or above was achieved and if intraoperative epidural supplementationwas not required. Sensory changes and motor changes were recorded. Results. Anaesthesia was effective in 97, 80, and 87% of patientsin the bupivacaine 8 mg, levobupivacaine 8 mg, and ropivacaine12 mg groups, respectively. Bupivacaine 8 mg was associatedwith a significantly superior success rate to that observedin the levobupivacaine group (P<0.05). It also provided alonger duration of analgesia and motor block (P<0.05 vs levobupivacaineand ropivacaine). Conclusions. The racemic mixture of bupivacaine combined withsufentanil remains an appropriate choice when performing Caesareansections under spinal anaesthesia. Br J Anaesth 2003; 91: 684–9     

Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age

Background. Levobupivacaine, the S(–)enantiomer of racemicbupivacaine is less cardiotoxic than racemic bupivacaine andthe R(+)enantiomer dexbupivacaine, while retaining similar localanaesthetic properties and potency to racemic bupivacaine. Thepharmacokinetic profiles of the two bupivacaine enantiomersdiffers and that of racemic bupivacaine may be age dependent.We examined the pharmacokinetics of levobupivacaine after itssingle shot caudal epidural administration in children. Methods. An open-label phase 2 study was undertaken to examinethe pharmacokinetics of levobupivacaine 0.25% 2 mg kg^–1in 49 children aged less than 2 yr, after single shot caudalepidural administration. Plasma concentrations were determinedat intervals up to 60 min after caudal injection. Results. Time to peak plasma concentration (T_max) ranged between5 and 60 min (median 30 min) and was reached later in childrenaged less than 3 months (P<0.005). Peak plasma concentration(C_max) ranged between 0.41 and 2.12 µg ml^–1 (median0.80, mean (SD) 0.91 (0.40) µg ml^–1). Conclusion. After the caudal epidural administration of levobupivacaine2 mg kg^–1 in children less than 2 yr of age, C_max waswithin the accepted safe range for racemic bupivacaine. T_maxvaried and occurred later in some children, particularly thoseaged less than 3 months. Sampling in future pharmacokineticstudies in this age group should extend beyond 60 min. Br J Anaesth 2004; 92: 218–22     

Comparison of ropivacaine 0.5% (in glucose 5%) with bupivacaine 0.5% (in glucose 8%) for spinal anaesthesia for elective surgery

Background. Hyperbaric solutions of ropivacaine have been usedsuccessfully to provide spinal anaesthesia. This study was designedto compare the clinical efficacy of hyperbaric ropivacaine withthat of the commercially available hyperbaric preparation ofbupivacaine. Methods. Forty ASA grade I–II patients undergoing lower-abdominal,perineal or lower-limb surgery under spinal anaesthesia wererecruited and randomized to receive ropivacaine 5 mg ml^–1(with glucose 50 mg ml^–1), 3 ml or bupivacaine 5 mg ml^–1(with glucose 80 mg ml^–1), 3 ml. The level and durationof sensory block, intensity and duration of motor block, andtime to mobilize and micturate were recorded. Patients wereinterviewed at 24 h and at 1 week to identify any residual problems. Results. All blocks were adequate for the proposed surgery,but there were significant differences between the two groupsin mean time to onset of sensory block at T10 (ropivacaine 5min; bupivacaine 2 min; P<0.005), median maximum extent (ropivacaineT7; bupivacaine T5; P<0.005) and mean duration of sensoryblock at T10 (ropivacaine 56.5 min; bupivacaine 118 min; P=0.001).Patients receiving ropivacaine mobilized sooner (ropivacainemean 253.5 min; bupivacaine 331 min; P=0.002) and passed urinesooner (ropivacaine mean 276 min; bupivacaine 340.5 min; P=0.01)than those receiving bupivacaine. More patients in the bupivacainegroup required treatment for hypotension (>30% decrease insystolic pressure; P=0.001). Conclusions. Ropivacaine 15 mg in glucose 50 mg ml^–1 providesreliable spinal anaesthesia of shorter duration and with lesshypotension than bupivacaine. The recovery profile for ropivacainemay be of interest given that more surgery is being performedin the day-case setting. Br J Anaesth 2003; 90: 304–8     

Pharmacokinetics of 0.75% ropivacaine and 0.5% bupivacaine after ilioinguinal-iliohypogastric nerve block in children

Background. Blockade of the ilioinguinal and iliohypogastricnerves is a useful procedure in paediatric patients undergoinginguinal surgery. Bupivacaine 2 mg kg^–1 has been recommendedfor this block. We compared the plasma concentrations of ropivacaineand bupivacaine following an ilioinguinal–iliohypogastricblock. Methods. Forty children scheduled for elective inguinal surgerywere randomized to receive 2 mg kg^–1 of either 0.75% ropivacaineor 0.5% bupivacaine. Surgical anaesthesia was maintained withmask inhalation of oxygen, nitrous oxide and sevoflurane. Venousblood samples were drawn at regular intervals for up to 2 hand plasma was separated. Total venous plasma concentrationswere determined by gas chromatography. Results. The groups were similar with respect to age, weightand dose of local anaesthetic. The peak plasma concentrationachieved was significantly higher in the bupivacaine group comparedwith the ropivacaine group (2.2 vs 1.2 µg ml^–1,P=0.025). The time to peak plasma concentration was significantlyshorter in the bupivacaine group (24 vs 35 min, P=0.024). Theinitial distribution half time of bupivacaine was significantlyshorter (3.6 vs 6.5 min, P=0.020) compared with that of ropivacaine. Conclusions. Bupivacaine is more rapidly absorbed from the injectionsite and leads to higher plasma concentrations than ropivacaine. Br J Anaesth 2002; 89: 438–41     

A comparative study of 0.25% ropivacaine and 0.25% bupivacaine for brachial plexus block.

The present study compares the effectiveness of 0.25% ropivacaine and 0.25% bupivacaine in 44 patients receiving a subclavian perivascular brachial plexus block for upper extremity surgery. The patients were assigned to two equal groups in this randomized, double-blind study; one group received ropivacaine 0.25% (112.5 mg) and the other, bupivacaine 0.25% (112.5 mg), both without epinephrine. Onset times for analgesia and anesthesia in each of the C-5 through T-1 brachial plexus dermatomes did not differ significantly between the two groups. The mean onset time for analgesia ranged from 11.2 to 20.2 min, and the mean onset time for anesthesia ranged from 23.3 to 48.2 min. The onset of motor block differed only with respect to paresis in the hand, with bupivacaine demonstrating a shorter onset time than ropivacaine. The duration of sensory and motor block also was not significantly different between the two groups. The mean duration of analgesia ranged from 9.2 to 13.0 h, and the mean duration of anesthesia ranged from 5.0 to 10.2 h. Both groups required supplementation with peripheral nerve blocks or general anesthesia in a large number of cases, with 9 of the 22 patients in the bupivacaine group and 8 of the 22 patients in the ropivacaine group requiring supplementation to allow surgery to begin. In view of the frequent need for supplementation noted with both 0.25% ropivacaine and 0.25% bupivacaine, we do not recommend using the 0.25% concentrations of these local anesthetics to provide brachial plexus block.     

A prospective study comparing the analgesic efficacy of levobupivacaine, ropivacaine and bupivacaine in pediatric patients undergoing caudal blockade

BACKGROUND: The aim of our study was to compare postoperative analgesic efficacy, analgesic duration and motor blockade of levobupivacaine, ropivacaine and bupivacaine administered caudally in equal concentrations to children undergoing elective minor surgery. METHODS: In the study, 182 children, aged 1-7 years, undergoing either inguinal hernia repair or orchidopexy, were randomly allocated to one of the three groups. They received via a caudal extradural either 1 ml x kg(-1) levobupivacaine 0.2% (Group L) or 1 ml x kg(-1) ropivacaine 0.2% (Group R) or 1 ml x kg(-1) bupivacaine 0.2% (Group B). RESULTS: No statistically significant difference was noted in age, weight, duration of the operation or level of the caudal block between the groups. The onset of analgesia was significantly later after levobupivacaine. Postoperative pain scoring evaluated with Children's and Infant's Postoperative Pain Scale observational scale showed no statistical difference between groups. Median postoperative analgesia was 5.75 h (SEMed: +/- 0.65) in Group L, 5.7 h (SEMed: +/- 0.8) in Group R and 5.35 h (SEMed: +/- 1.3) in Group B the difference being statistically nonsignificant. CONCLUSIONS: The degree of motor block was significantly less after ropivacaine and levobupivacaine during the first 2 h postoperatively.     

Epidural analgesia with 0.15% ropivacaine plus sufentanil 0.5 microgram ml-1 versus 0.10% bupivacaine plus sufentanil 0.5 microgram ml-1: a double-blind comparison during labour

Background. Ropivacaine has been claimed to produce less motorblock than bupivacaine during epidural analgesia. However, thisadvantage has not been clearly confirmed in obstetric studiesusing low analgesic concentrations in a ratio close to thatsuggested to be equianalgesic. Methods. This double-blind, randomized, prospective study wasperformed in 140 parturients who requested epidural analgesia.After a lumbar epidural catheter had been placed, patients receivedeither 0.10% bupivacaine plus sufentanil 0.5 µg ml^–1or 0.15% ropivacaine plus sufentanil 0.5 µg ml^–1followed by a continuous infusion. Additional boluses were usedfor inadequate levels of analgesia. Visual analogue pain scores,motor block, level of sensory block, supplementary boluses andmain characteristics of labour were recorded. Results. No differences were observed between the two groupsfor pain scores, total volume of anaesthetic solution used [59(23) and 57 (24) ml in the bupivacaine and ropivacaine groupsrespectively], duration of labour, mode of delivery, side-effectsor satisfaction score. The incidence of motor block was notstatistically different between the groups (54 and 69% in thebupivacaine and ropivacaine groups respectively, P=0.07). However,when motor block occurred, survival analysis showed that itoccurred sooner in the course of labour with ropivacaine comparedwith bupivacaine (log rank test, P=0.012). Conclusion. Combined with sufentanil 0.5 µg ml^–1,0.10% bupivacaine and 0.15% ropivacaine produce effective andequivalent analgesia during labour, with similar incidencesof motor block. Br J Anaesth 2002; 88: 809–13     

Ropivacaine 0.25% is as effective as bupivacaine 0.25% in providing surgical anaesthesia for lumbar plexus and sciatic nerve block in high-risk patients: preliminary report

Ropivacaine is potentially less cardiotoxic and neurotoxic than bupivacaine. The aim of this study was to compare the effectiveness of ropivacaine 0.25% and bupivacaine 0.25% for surgical anaesthesia and postoperative analgesia during lumbar plexus and sciatic nerve block in high-risk patients. We performed combined lumbar plexus and sciatic nerve blockade on 62 consecutive ASA III or IV patients undergoing unilateral hip or femur surgery. The first 30 patients received bupivacaine (Group 1) and the remaining 32 patients received ropivacaine (Group 2). Perioperative management was otherwise similar The groups were compared for the time of onset of the block, additional analgesics and sedatives required, time from end of surgery to the first analgesic requirement and the need for rescue analgesia. Ninety percent (29/32) of the patients in the ropivacaine group and 86% (26/30) of the patients in the bupivacaine group reached surgical anaesthesia. The time from the end of the surgery to the first analgesic requirement was similar between the two groups (10.3 +/- 5.2 hours for ropivacaine, 11.2 +/- 4.6 hours for bupivacaine). There was no statistically significant difference between the two groups in any of the measured variables (P > 0.05). The results of this preliminary study suggest that ropivacaine 0.25% is as effective as bupivacaine 0.25% when used for blocking lumbar plexus and sciatic nerve in high-risk patients undergoing hip or femur surgery.     

Spinal anesthesia: comparison of plain ropivacaine, bupivacaine and levobupivacaine for lower abdominal surgery

This study was performed to compare the anesthetic efficacy and safety of three local anesthetic agents: racemic bupivacaine and its two isomers: ropivacaine and levobupivacaine, in patients undergoing lower abdominal surgery. One hundred-twenty patients, ASA I-III, were randomized to receive an intrathecal injection of one of three local anesthetic solutions. Group A (n = 40) received 3 ml of isobaric bupivacaine 5 mg/ml (15 mg). Group B (n = 40) received 3 ml of isobaric ropivacaine 5 mg/ml (15 mg). Group C (n = 40) received 3 ml of isobaric levobupivacaine 5 mg/ml (15 mg). The onset and duration of sensory block at dermatome level T8, maximum upper spread of sensory block, time for 2-segment regression of sensory block as well as the onset, intensity and duration of motor block were recorded, as were any adverse effects, such as bradycardia, hypotension, hypoxia, tremor, nausea and/or vomiting. Time to unassisted standing up and voluntary micturition was also recorded. The onset of motor block was significantly faster in the bupivacaine group compared with that in the ropivacaine group and almost the same of that in the levobupivacaine group (P < 0.05). Ropivacaine presented a shorter duration of both motor and sensory block than bupivacaine and levobupivacaine (P < 0.05). Bupivacaine required more often the use of a vasoactive drug (ephedrine) compared to both ropivacaine and levobupivacaine and of a sympathomimetic drug (atropine) compared to the ropivacaine group.     

Extradural anaesthesia for Caesarean section: a double-blind comparison of 0.5% ropivacaine with 0.5% bupivacaine

Seventy-three parturients for elective Caesarean section wereallocated randomly to receive extradural block with 20 ml ofeither 0.5% ropivacaine or 0.5% bupivacaine. If the block didnot reach T6 within 30 mm, another 5 ml of solution was given.If needed, a further 5 ml was given 45 mm after the main dose.The mean total dose of bupivacaine was 23.1 ml (n = 35) andof ropivacaine 23.7 ml (n = 37). There was no significant differencebetween the groups in the profile of sensory block produced.There was no significant difference in the time of onset, orintensity of motor block between the groups but the durationof motor block was significantly shorter in the ropivacainegroup. There was no significant difference in neonatal outcome,as assessed by Apgar score, umbilical cord bloodgas tensionsat delivery or the neurological and adaptive capacity score2 and 24 h after delivery. (Br. J. Anaesth. 1995; 74: 512–516)     

Pain relief and motor function during continuous interscalene analgesia after open shoulder surgery: a prospective, randomized, double-blind comparison between levobupivacaine 0.25%, and ropivacaine 0.25% or 0.4%

BACKGROUND AND OBJECTIVES: To compare pain relief and motor impairment of 0.25% levobupivacaine with either an equivalent (0.25%) or equipotent (0.4%) concentration of ropivacaine for continuous interscalene block after open shoulder surgery. METHODS: Seventy-two adult patients scheduled for elective major shoulder surgery received an interscalene injection of mepivacaine 1.5% 30 mL followed by 24 h patient-controlled interscalene analgesia (basal infusion rate: 5 mL h-1; incremental bolus: 2 mL; lockout period: 10 min; maximum boluses per hour: 4) with either 0.25% levobupivacaine (n = 24), 0.25% ropivacaine (n = 24) or 0.4% ropivacaine (n = 24). A blinded observer recorded the evolution of pain relief and recovery of motor block during the first 24 h. Motor function was assessed as the maximum pressure developed while squeezing a sphygmomanometer cuff with the blocked hand. The reduction from preoperative values was considered as an index of motor impairment. RESULTS: No differences were reported among the three groups in the quality of postoperative analgesia. The number of incremental patient-controlled interscalene analgesia doses, total volume of local anaesthetic infused during the 24-h patient-controlled interscalene analgesia, and number of rescue ketoprofen analgesia were higher in the ropivacaine 0.25% group than in the other two groups (P = 0.0005). The hand strength recovered to >or=90% of baseline values within the first 24 h of infusion in all groups, without differences among the three groups. CONCLUSION: When providing patient-controlled interscalene analgesia after open shoulder surgery 0.25% levobupivacaine and 0.4% ropivacaine performed equally in terms of pain relief, motor block and number of patient-controlled boluses required, while patients receiving 0.25% ropivacaine needed significantly more boluses and rescue analgesia to control their pain.     

Epidural test dose with levobupivacaine and ropivacaine: determination of ED(50) motor block after spinal administration

Background. When a test is required to detect a possible intrathecalcatheter, many would seek to use the same local anaestheticas that used for epidural analgesia. The rapid onset of inappropriatemotor block after a local anaesthetic administered epidurallyimplies intrathecal spread. Because of claims of greater sensory–motorseparation, or because of reduced potency compared with bupivacaine,the efficacy of the new local anaesthetics in intrathecal testinghas been questioned. The aim of this study was to establishthe feasibility of a test dose for an inadvertent intrathecalcatheter using ropivacaine and levobupivacaine, and to establishthe dose required. Methods. Sixty women undergoing elective Caesarean section witha combined spinal– epidural technique were enrolled intothis prospective, double-blind sequential allocation study.The women were randomized to receive plain levobupivacaine 0.5%or ropivacaine 0.5% intrathecally. The dose was determined accordingto up–down sequential allocation. The end-point was anyevidence of lower limb motor block within 5 min of injection. Results. The ED₅₀ motor block at 5 min was 4.8 mg (95% CI, 4.49,5.28) for levobupivacaine and 5.9 mg (95% CI, 4.82, 6.98) forropivacaine (95% CI difference, 0.052, 1.98) (P=0.04). The estimatedED₉₅ motor block was 5.9 mg (95% CI 5.19, 6.71) for levobupivacaineand 8.3 mg (95% CI, 6.30, 10.44) for ropivacaine. The potencyratio between the two drugs was 0.83 (95% CI, 0.69, 0.99). Conclusions. Both local anaesthetics produce evidence of motorblock within 5 min of intrathecal injection and could serveas tests of intrathecal administration. Derived ED₉₅ valuessuggest 10 mg doses should be effective, but this study didnot measure predictive value. Ropivacaine is less potent formotor block than levobupivacaine by a factor of 0.83 (P<0.04). Br J Anaesth 2004; 92: 850–3     

Minimum local analgesic doses of ropivacaine, levobupivacaine, and bupivacaine for intrathecal labor analgesia

BACKGROUND: Doses for intrathecal opioid-local anesthetic mixtures have been arbitrarily chosen. The aim of this study was to compare the analgesic efficacies of intrathecal ropivacaine, levobupivacaine, and bupivacaine for labor analgesia and to determine the analgesic potency ratios for these three drugs. For this purpose, the authors used the up-down sequential allocation model, which estimates the minimum local analgesic dose for intrathecal local anesthetic. METHODS: Ninety-seven nulliparous term parturients in spontaneous labor, requesting combined spinal-epidural analgesia, were randomly allocated to one of three groups to receive 0.25% spinal ropivacaine, levobupivacaine, or bupivacaine. The initial dose of the local anesthetic drug was chosen to be 2.5 mg, and the testing interval was set at 0.25 mg. The subsequent doses were determined by the response of the previous parturient. Efficacy was accepted if the visual analog pain score decreased to 10 mm or less on a 100-mm scale within 30 min. The minimum local analgesic dose was calculated using the method of Dixon and Massey. RESULTS: The intrathecal minimum local analgesic dose was 3.64 mg (95% confidence interval, 3.33-3.96 mg) for ropivacaine, 2.94 (2.73-3.16) mg for levobupivacaine, and 2.37 (2.17-2.58) mg for bupivacaine. The relative analgesic potency ratios were 0.65 (0.56-0.76) for ropivacaine:bupivacaine, 0.80 (0.70-0.92) for ropivacaine:levobupivacaine, and 0.81 (0.69-0.94) for levobupivacaine:bupivacaine. There were significant trends (P levobupivacaine > ropivacaine.     

Double-blind randomized controlled trial of caudal versus intravenous S(+)-ketamine for supplementation of caudal analgesia in children

Background. The postoperative analgesic efficacy of S(+)-ketamineafter caudal or i.v. administration following sub-umbilicalsurgery in children was studied to investigate its principalsite of analgesic action. Methods. Sixty children undergoing caudal block during generalanaesthesia for hernia repair or orchidopexy were prospectivelyrandomized to one of three groups: the bupivicaine group receivedplain bupivacaine 0.25% 1 ml kg^–1; the caudal ketaminegroup received caudal plain bupivacaine 0.25% 1 ml kg^–1with S(+)-ketamine 0.5 mg kg^–1; the i.v. ketamine groupreceived caudal plain bupivacaine 0.25% 1 ml kg^–1 plusS(+)-ketamine 0.5 mg kg^–1 i.v.. Postoperative measurementsincluded analgesic requirements and modified objective painscore for the first 24 h. Results. The median time to first analgesia was significantlylonger in the caudal ketamine group (10 h) than in the i.v.ketamine (4.63 h) or bupivacaine (4.75 h) groups (P=0.01). Significantlyfewer doses of analgesia were required over the first postoperative24 h by subjects in the caudal ketamine group (median 1) comparedwith the i.v. ketamine (median 2) or bupivacaine (median 2.5)groups (P<0.05). There was no difference between the groupsin the incidence of postoperative nausea and vomiting or psychomotorreactions. Conclusions. We have demonstrated that the addition of caudalS(+)-ketamine to bupivacaine prolongs the duration of postoperativeanalgesia. However, the same dose of i.v. S(+)-ketamine combinedwith a plain bupivacaine caudal provides no better analgesiathan caudal bupivacaine alone, indicating that the principalanalgesic effect of caudal S(+)-ketamine results from a localneuroaxial rather than a systemic effect. Br J Anaesth 2004; 92: 344–7     

Comparison of 0.25% levobupivacaine and 0.25% bupivacaine for posterior approach interscalene brachial plexus block

Purpose  

This study compares the onset time and quality of posterior approach interscalene brachial plexus block produced by 0.25% levobupivacaine and 0.25% bupivacaine.     

Minimum Local Analgesic Doses of Ropivacaine, Levobupivacaine, and Bupivacaine for Intrathecal Labor Analgesia

Background: Doses for intrathecal opioid-local anesthetic mixtures have been arbitrarily chosen. The aim of this study was to compare the analgesic efficacies of intrathecal ropivacaine, levobupivacaine, and bupivacaine for labor analgesia and to determine the analgesic potency ratios for these three drugs. For this purpose, the authors used the up-down sequential allocation model, which estimates the minimum local analgesic dose for intrathecal local anesthetic.

Methods: Ninety-seven nulliparous term parturients in spontaneous labor, requesting combined spinal-epidural analgesia, were randomly allocated to one of three groups to receive 0.25% spinal ropivacaine, levobupivacaine, or bupivacaine. The initial dose of the local anesthetic drug was chosen to be 2.5 mg, and the testing interval was set at 0.25 mg. The subsequent doses were determined by the response of the previous parturient. Efficacy was accepted if the visual analog pain score decreased to 10 mm or less on a 100-mm scale within 30 min. The minimum local analgesic dose was calculated using the method of Dixon and Massey.

Results: The intrathecal minimum local analgesic dose was 3.64 mg (95% confidence interval, 3.33-3.96 mg) for ropivacaine, 2.94 (2.73-3.16) mg for levobupivacaine, and 2.37 (2.17-2.58) mg for bupivacaine. The relative analgesic potency ratios were 0.65 (0.56-0.76) for ropivacaine:bupivacaine, 0.80 (0.70-0.92) for ropivacaine:levobupivacaine, and 0.81 (0.69-0.94) for levobupivacaine:bupivacaine. There were significant trends (P <= 0.021) for greater motor block with bupivacaine and levobupivacaine.     

A double-blind comparison of 0.25% ropivacaine and 0.25% bupivacaine for extradural analgesia in labour

Ropivacaine is a new aminoamide local anaesthetic. Compared with bupivacaine, ropivacaine possesses a higher threshold for systemic toxicity and a high selectivity for sensory fibres. We have compared prospectively these two agents in a concentration of 0.25% for extradural analgesia in labour. A total of 104 parturients requesting extradural analgesia were randomized to receive either ropivacaine or bupivacaine. The women in the bupivacaine group required more top-up doses to maintain analgesia (median 3.0 vs 2.0) (P < 0.05). The onset of sensory block, quality of analgesia, ultimate level of maximum sensory block and maternal satisfaction were similar in both groups. The incidence, intensity and duration of motor block were slightly but not significantly less in the ropivacaine group. The ropivacaine group had a higher incidence of spontaneous vaginal delivery (70.59% vs 52.00%). There was no significant difference in neonatal outcome as assessed by Apgar scores, umbilical acid-base status and neurological and adaptive capacity score at 2 and 24 h after delivery. We conclude that ropivacaine and bupivacaine in a concentration of 0.25% produced comparable analgesia for pain relief of labour with no detectable adverse effect on the neonate.