Levobupivacaine 0.2% or 0.125% for Continuous Sciatic Nerve Block: A Prospective, Randomized, Double-Blind Comparison with 0.2% Ropivacaine

Differential blockade, comparative study of different ropivacaine concentrations (0.75%; 0.2%; 0.12%) for ultrasound guided sciatic and femoral nerve blocks in calves: Prospective cross-over study

Pharmacodynamic understanding of the different local anesthetic concentrations allows adapting their use to diverse clinical/surgical procedures, such as intraoperative and/or postoperative analgesia. A crossover study was performed, where 6 calves (5 male and 1 female), weighing 120 ± 28 Kg, were subjected to combined sciatic and femoral nerve block using three ropivacaine concentrations. The treatments were: R0.75, using 0.75% ropivacaine; R0.2, 0.2% ropivacaine; and R0.12%, 0.12% ropivacaine. All treatments were performed with ultrasound and neurostimulation assistance, and a volume of 0.1 mL/kg of the respective local anesthetic solution was administered in each block point. The sites of mechanical nociceptive threshold (MNT) evaluation were based on the calf pelvic limb dermatomes. The proportion between desensitized areas, MNT elevation time and level of ataxia were registered. Elevation of MNT occurred in 100% of the tested areas in the R0.75 and R0.2 treatments, and in 82% of the R0.12 treatment. Mean MNT elevation times were 9.5 ± 0.7 h for R0.75, 6 ± 0.8 for R.02, and 2.4 ± 2.3 for R0.12, differing significantly between all treatments. No difference was observed between MNT elevation time and ataxia duration time, in each treatment. It is concluded that the duration of sensory-motor effects is dose-dependent, but there was not possible to detect block selectivity as the concentrations was reduced. More desensitized areas and extension were obtained with the use of higher concentrations.

Levobupivacaine Consumption in Automated Intermittent Bolus in Ultrasound Guided Subparaneural Sciatic Nerve Catheters: A Prospective Double-Blind Randomized Trial

Purpose

Continuous sciatic nerve blocks have proven benefits for postoperative analgesia after foot surgery. However, the optimal mode of administration remains a point of debate. Ultrasound guided subparaneural injection accelerates onset time and increases duration after a single shot sciatic nerve block. This double blind prospective randomized trial compares the 48-hour local anesthetic (LA) dose consumption of an automated intermittent bolus technique to a continuous infusion regimen in a subparaneural sciatic nerve catheter after hallux valgus surgery.

Patients and Methods

Patients scheduled for hallux valgus surgery were randomized to receive either a continuous infusion of levobupivacaine 0.125% at 5mL/h (group A) or an intermittent automated bolus of 9.8 mL every 2 hours with a background of 0.1 mL/h (group B), both with a PCA bolus of 6 mL and lockout of 30 minutes. The 48 hour LA consumption, PCA boluses, Numeric Rating Scale (NRS), satisfaction and return of normal sensation were recorded.

Results

Sixteen patients were excluded because of protocol violation or technical problems and 42 patients remained for analysis. The 48 hour ropivacaine consumption was higher in group A (293 ±60 mL) than group B (257±33 mL). The median and highest NRS scores and patient satisfaction were not statistically different between groups. Normal sensation returned after 75 ± 22 hours (group A) and 70 ± 17 hours (group B).

Conclusion

Programmed bolus administration in subparaneural sciatic nerve catheters reduces LA consumption 48 hours after surgery with equal analgesia and patient satisfaction. Return of sensation is variable and can last more than 75 hours.

A prospective, randomized, open label, controlled study investigating the efficiency and safety of 3 different methods of rectus sheath block analgesia following midline laparotomy

BACKGROUND

There is a controversy regarding the efficacy of rectus sheath block (RSB). The aim of the present study was to evaluate analgesic efficacy and safety of three different methods of RSB in postoperative pain management after midline laparotomy.

METHODS

A prospective, randomized, controlled, open-label clinical trial with 4 parallel groups was conducted in a tertiary care hospital in Finland. A total of 57 patients undergoing midline laparotomy were randomized to the control group (n = 12) or to 1 of the 3 active RSB analgesia groups: single-dose (n = 16), repeated-doses (n = 12), or continuous infusion (n = 17). Opioid consumption with iv-patient-controlled analgesia pump was recorded, and pain scores and patients' satisfaction were surveyed on an 11-point numeric rating scale for the first 48 postoperative h. Plasma concentrations of oxycodone and levobupivacaine were analyzed. All adverse events during the hospital stay were recorded.

RESULTS

Oxycodone consumption was less during the first 12 h in the repeated-doses and in the continuous infusion groups (P = .07) and in numerical values up to 48 h in the repeated-doses group. Plasma oxycodone concentrations were similar in all 4 groups. Pain scores were lower in the repeated-doses group when coughing during the first 4 h (P = .048 vs. control group), and at rest on the first postoperative morning (P = .034 vs. the other 3 groups) and at 24 h (P = .006 vs. the single-dose group). All plasma concentrations of levobupivacaine were safe. The patients' satisfaction was better in the repeated-doses group compared with the control group (P = .025). No serious or unexpected adverse events were reported.

CONCLUSIONS

RSB analgesia with repeated-doses seems to have opioid sparing efficacy, and it may enhance pain relief and patients' satisfaction after midline laparotomy.

A Randomized Controlled Trial Assessing the Effect of a Continuous Subcutaneous Infusion of Local Anesthetic Following Elective Surgery to the Great Toe

Local anesthetic use for wound infusions, single injection, and continuous nerve blocks for postoperative analgesia is well established. No study has investigated the effect of a continuous block of the saphenous and superficial peroneal nerves at the level of the ankle joint following first ray surgery. A double blind randomized controlled trial was designed. One hundred patients with hallux valgus and rigidus requiring surgical correction were recruited and randomized to receive a postoperative continuous infusion at the ankle of normal saline or ropivacaine for 24 hours. Pain scores were recorded on postoperative days 1 and 7. There were more females than males. Follow-up was 100%. There were no significant differences in demographic data between the 2 randomized groups. There was no significant difference between the absolute visual analog scale scores on day 1 (P = .14) and day 7 (P = .16); nor was there a significant difference in reduction in scores between days 1 and 7 (P = .70). This study has shown no benefit to postoperative analgesia with the use of a continuous infusion of ropivacaine at the ankle. We, therefore, cannot currently recommend its use in the way described. Further studies may still identify a role for continuous local anesthetic infusions at the ankle to improve postoperative analgesia.

LEVELS OF EVIDENCE

Level I : Prospective randomised control trial.

Ultrasound-guided femoro-sciatic nerve block for post-operative analgesia after below knee orthopaedic surgeries under subarachnoid block: Comparison between clonidine and dexmedetomidine as adjuvants to levobupivacaine

Background and Aims:

The advent of ultrasonographic-guided techniques has led to increased interest in femoro-sciatic nerve block (FSNB) for lower limb surgeries. α₂-agonists have been used recently as adjuvants to local anaesthetics in nerve blocks. We aimed to compare equal doses of clonidine or dexmedetomidine as an adjuvant to levobupivacaine in FSNB for post-operative analgesia.

Methods:

Ninety patients scheduled to undergo below knee orthopaedic surgeries under subarachnoid block were divided into three groups: Group LL (n = 30) patients received 38 mL of 0.125% levobupivacaine with 2 mL normal saline, Group LD (n = 30) patients received 38 mL of 0.125% levobupivacaine with 0.5 μg/kg dexmedetomidine and Group LC (n = 30) received 38 mL of 0.125% levobupivacaine with 0.5 μg/kg clonidine in saline to make total drug volume of 40 mL. The primary and secondary outcome variables were duration of analgesia and rescue analgesic requirement, verbal rating score respectively. Continuous variables were analysed with analysis of variance or the Kruskal–Wallis test on the basis of data distribution. Categorical variables were analysed with the contingency table analysis and the Fisher's exact test.

Results:

Duration of analgesia was prolonged with dexmedetomidine (10.17 ± 2.40 h) and clonidine (7.31 ± 1.76 h) as compared to control (4.16 ± 1.04 h, P = 0.00). Significantly lower pain scores were observed in dexmedetomidine group as compared to clonidine up to 8 h post-operatively.

Conclusion:

Equal doses of clonidine or dexmedetomidine added to levobupivacaine prolonged the duration of analgesia, decreased requirement of rescue analgesia. Dexmedetomidine delays the requirement of rescue analgesics with better pain scores as compared to clonidine.

Continuous postoperative pain control using a multiple-hole catheter after iliac bone grafting: comparison between ropivacaine and levobupivacaine

The aim of this study was to compare the analgesic effects of ropivacaine and levobupivacaine in continuous infiltration anaesthesia delivered via a multiple-hole catheter for the purpose of postoperative analgesia after iliac bone grafting. Thirty-four patients scheduled for iliac bone grafting in the maxillofacial region participated in this study. The patients were randomized to a ropivacaine group (Ropi group) and a levobupivacaine group (Levo group). After harvesting the iliac bone for grafting, a multiple-hole catheter was placed on the periosteum of the iliac bone. When surgery was completed, continuous administration was started at 4 ml/h of 0.2% ropivacaine (Ropi group) or 0.25% levobupivacaine (Levo group). Pain was evaluated in the recovery room and at 4h after surgery, as well as at 9:00 and 18:00 on postoperative days 1, 2, and 3, using a visual analogue scale. Side effects were also recorded. No significant difference in the visual analogue scale scores at rest or in motion was observed between the two groups. In addition, there were no side effects in the two groups. Both 0.2% ropivacaine and 0.25% levobupivacaine provided comparable analgesic effects in continuous infiltration anaesthesia delivered via a multiple-hole catheter after iliac bone grafting.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy - preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg^-1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg^-1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg^-1) or NaCl 0.9% (group C; 0.3 mL kg^-1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg^-1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg^-1). Data were compared using Mann-Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

Update on the clinical utility and practical use of ropivacaine in Chinese patients

We reviewed the Chinese and English literature for efficacy and tolerability data as well as pharmacological properties of ropivacaine in Chinese patients. Ropivacaine is a long-acting amide local anesthetic agent that elicits nerve block via reversible inhibition of sodium ion influx in nerve fibers. The available evidence in the literature on anesthesia practice indicates that ropivacaine produces equally surgical sensory block and postoperative and obstetrics analgesia with good maternal and fetal outcome to those of bupivacaine or levobupivacaine. It appears to be associated with comparable onset, quality, and duration of sensory block, but with a lower incidence or grade of motor block, compared to bupivacaine. The satisfaction of both patients and surgeons is high when ropivacaine is used. Thus, ropivacaine appears to be an important option for regional anesthesia and for the management of postoperative and labor pain, with its enhanced sensorimotor differentiation blockage at lower concentrations and enhanced safety at higher concentrations.

[Comparison of 3 combinations of 0.5% levobupivacaine and 1% mepivacaine in popliteal sciatic block in hallux valgus outpatient surgery]

BACKGROUND

To compare 3 combinations of 0.5% levobupivacaine (L) and 1% mepivacaine (M) for popliteal block for hallux valgus surgery.

METHODS

Prospective, double blind study of 120 patients undergoing unilateral hallux valgus outpatient surgery with posterior popliteal block with ultrasound-guided single injection. Patients were randomly allocated into three groups: G1: 20mL L+10mL M; G2: 10mL L+20mL M; and G3: 15mL L+15mL M. Recorded variables were: time of block, onset and reversal times for tibial and peroneal nerves block; postoperative pain until the 7(th) day by means of visual analogue scale (VAS), simple descriptive scale and the quality of nocturnal rest, complications, and patient satisfaction. ANOVA and chi2 were applied in the statistical analysis, with a P<0.05 considered significant.

RESULTS

Groups were homogeneous for demographic and surgical characteristics. None of the patients required intraoperative complementary analgesia or anaesthesia. Block onset was significantly longer in G1 than in G2 and G3 (39.4±14.7 versus 32.2±16.5 and 33.2±12minutes). Recovery time from sensory and motor block was significantly longer in G1 than in G2 and G3 (29.5±9.3 versus 22.2±8.2 and 24.8±7.9hours). Postoperative pain level was below VAS 30 (1-100) in the three groups; none of the patients experienced severe pain. Maximum pain level appeared at 24h postoperatively. Patient satisfaction was high and there were no complications.

CONCLUSIONS

Block onset time and anaesthetic efficacy was adequate in the three groups. The combination of 20mL levobupivacaine 0.5% with 10mL mepivacaine 1% provide a good alternative for a lasting postoperative analgesia.

Continuous femoral nerve blocks: decreasing local anesthetic concentration to minimize quadriceps femoris weakness

BACKGROUND

Whether decreasing the local anesthetic concentration during a continuous femoral nerve block results in less quadriceps weakness remains unknown.

METHODS

Preoperatively, bilateral femoral perineural catheters were inserted in subjects undergoing bilateral knee arthroplasty (n = 36) at a single clinical center. Postoperatively, right-sided catheters were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h; bolus 4 ml) or 0.4% (basal 3 ml/h; bolus 1 ml), with the left catheter receiving the alternative concentration/rate in an observer- and subject-masked fashion. The primary endpoint was the maximum voluntary isometric contraction of the quadriceps femoris muscles the morning of postoperative day 2. Equivalence of treatments would be concluded if the 95% CI for the difference fell within the interval -20%-20%. Secondary endpoints included active knee extension, passive knee flexion, tolerance to cutaneous electrical current applied over the distal quadriceps tendon, dynamic pain scores, opioid requirements, and ropivacaine consumption.

RESULTS

Quadriceps maximum voluntary isometric contraction for limbs receiving 0.1% ropivacaine was a mean (SD) of 13 (8) N · m, versus 12 (8) N · m for limbs receiving 0.4% [intrasubject difference of 3 (40) percentage points; 95% CI -10-17; P = 0.63]. Because the 95% CI fell within prespecified tolerances, we conclude that the effect of the two concentrations were equivalent. Similarly, there were no statistically significant differences in secondary endpoints.

CONCLUSIONS

For continuous femoral nerve blocks, we found no evidence that local anesthetic concentration and volume influence block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Update on local anesthetics: focus on levobupivacaine

In recent years levobupivacaine, the pure S (−)-enantiomer of bupivacaine, emerged as a safer alternative for regional anesthesia than its racemic parent. It demonstrated less affinity and strength of depressant effects onto myocardial and central nervous vital centers in pharmacodynamic studies, and a superior pharmacokinetic profile. Clinically, levobupivacaine is well tolerated in a variety of regional anesthesia techniques both after bolus administration and continuous postoperative infusion. Reports of toxicity with levobupivacaine are scarce and occasional toxic symptoms are usually reversible with minimal treatment with no fatal outcome. Yet, levobupivacaine has not entirely replaced bupivacaine in clinical practice. In anesthesia and analgesia practice, levobupivacaine and bupivacaine produce comparable surgical sensory block with similar adverse side effects, and equal labor pain control with comparable maternal and fetal outcome. The equipotency of the two drugs has been recently questioned, prompting clinicians to increase the dose of levobupivacaine in an attempt to ensure adequate anesthesia and analgesia and offsetting, therefore, the advantages of less motor block with levobupivacaine. In this review we aim to discuss the pharmacological essentials of the safer profile of levobupivacaine, and analyze the evidence regarding the current clinical indications.

Quality of reporting of regional anesthesia outcomes in the literature

OBJECTIVE

Consistent and reliable standards for reporting of regional anesthetic adverse events are lacking. The quality of reporting of regional anesthetic morbidity has not been assessed critically.

AIM

To evaluate quality of regional anesthesia outcomes reporting. Methods. Published retrospective or prospective observational cohort or randomized controlled trials in peer-reviewed journals were reviewed, and judged according to seven criteria related to quality of reporting of regional anesthesia complications: method of accrual, duration of data collection, definition of complication, morbidity and mortality rates, grade of complication severity, exclusion criteria, and study follow up. Differences in reporting outcomes according to study design, sample size and time period were compared.

RESULTS

Ninety-one articles published from 1996-2006 involving 8,833 patients were analyzed. The majority of studies (75%) met < or =4 reporting criteria. Recently published, prospective studies with >200 patients were associated with significantly higher-quality reporting (P < 0.05). Fewer than 50% of studies reported at least one recognized, accepted complication with defined criteria or indicated duration of follow up. Reporting compliance was worse (29%) for reporting of actual morbidity rates, and complications leading to death. Complication severity grading related to regional anesthesia was reported in 2% of studies.

CONCLUSION

Consistent and comparative regional anesthesia outcome data are lacking in peer-reviewed journals. A graded regional anesthetic morbidity and mortality system according to the intensity of therapy required for the treatment of the defined complication is proposed, along with a structured format for the reporting of regional anesthesia complications according to defined reporting standards.

Arthroscopic lateral release and percutaneous distal osteotomy for hallux valgus: a preliminary report

Distal osteotomy of the first metatarsal is frequently used for the treatment of hallux valgus deformity. The great toe arthroscopy is a safe procedure to perform a distal soft tissue release and a complete evaluation of the first metatarsal-phalangeal joint. The aim of this study was to evaluate the results of the arthroscopic distal soft tissue release with a distal percutaneous osteotomy in the treatment of hallux valgus deformity. From January 1, 2003, to August 1, 2006, 59 consecutive procedures were performed in 49 patients. Clinical evaluation was calculated using the hallux score of the American Orthopedic Foot and Ankle Society (AOFAS). The mean follow up was 31.48 (range, 12 to 48) months and the AOFAS score improved from 45 (range, 30 to 65) points to 90.61 (range, 75 to 100). The excellent results obtained encourage the authors to go on treat the hallux valgus deformity with this combination of two minimal invasive procedures.

A "new" automated bolus technique for continuous popliteal block: a prospective, randomized comparison with a continuous infusion technique

BACKGROUND

We designed the present, prospective, randomized, double-blind study to compare the administration of an automated intermittent bolus dose with a conventional technique of continuous infusion of local anesthetic for postoperative analgesia in continuous popliteal sciatic nerve blockade.

METHODS

Forty-four patients undergoing hallux valgus repair were randomly assigned to receive either a continuous infusion of 0.125% levobupivacaine with an infusion rate of 5 mL/h (continuous infusion group, n=22) or automated bolus doses of 5 mL every hour of the same local anesthetic (automated bolus group, n=22) for 24 h. Postoperative pain scores were assessed using a verbal rating pain score. The amount of rescue tramadol medication for pain was also recorded.

RESULTS

In patients of the automated bolus group there was a reduction in pain scores (P<0.05) during the postoperative period, when compared to patients of the continuous infusion group. Five patients in the automated bolus group (24%) and 11 patients of the continuous group (52%) required rescue tramadol analgesia (P=0.055).

CONCLUSION

The present investigation demonstrated that local anesthetic administered by an automated bolus technique provided better postoperative pain relief than a continuous infusion technique for continuous popliteal nerve block after foot surgery.

Multi-modal-analgesia for pain management after Hallux Valgus surgery: a prospective randomised study on the effect of ankle block

BACKGROUND

Pain and emesis are the two major complaints after day case surgery. Local anaesthesia has become an important part of optimizing intra and post-operative pain treatment, but is sometimes not entirely sufficient. The aim of the present study was to study the effect of adding an ankle block to a multi-modal analgesic approach on the first 24-hour-need for rescue analgesia in patients undergoing elective Hallux Valgus surgery.

TYPE OF STUDY

Prospective, randomized patient-blind study comparing ankle block with levo-bupivacaine, lidocaine and Saline placebo control.

METHODS

Ninety patients were studied comparing ankle block (15 cc) using levo-bupivacaine 2.5 mg/ml, lidocaine 10 mg/ml or placebo (saline) on day-case elective Hallux Valgus surgery, supported by general anaesthesia in all cases. Primary study endpoint was number of patient's requiring oral analgesics during the first 24 post-operative hours.

RESULTS

Ankle block had no effect on need for rescue analgesia and pain ratings during the 1st 24 postoperative hours, there was no difference seen between placebo and any of the two active local anaesthesia studied. The only differences seen was that both lidocaine and levo-bupivacaine reduced the intra-operative need for anaesthetic (sevoflurane) and that levo-bupivacaine patients had a lower need as compared to the lidocaine patients for oral analgesics during the afternoon of surgery.

CONCLUSION

Adding a single shot ankle block to a multi-modal pain management strategy reduces the need for intra-operative anaesthesia but has no major impact of need of rescue analgesics or pain during the first 24-hour after surgery.

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.

Continuous peripheral nerve blocks: state of the art

PURPOSE OF REVIEW

This review was performed through a Medline research to evaluate articles published between January 2004 and April 2005. Technical procedures, indications, drugs, infusion regimens, and complications of continuous peripheral nerve blocks were considered.

RECENT FINDINGS

A total of 27 articles were reviewed. With respect to technical procedures, the authors focused on advantages of stimulating catheters or ultrasound guidance. With the help of these techniques, a correct catheter placement as close to the targeted nerve as possible was obtained. The total amount of local anesthetic administered was thereby reduced. Using ultrasound needle guidance, the spread of local anesthetic around the nerve could be visualized. Articles dealing with the choice of local anesthetic showed equianalgesia and equipotency of continuous perineural infusion of levobupivacaine 0.125% and ropivacaine 0.2%. The best infusion regimen for postoperative analgesia appears to be a combination of a preset basal rate administered together with small bolus doses in almost all continuous peripheral nerve blocks. Overall, complications such as infections, local anesthetic toxic plasma levels, hematoma formation, or nerve injury seem to be rare in continuous peripheral nerve blockade.

SUMMARY

Continuous peripheral nerve blockade is an effective and safe technique for postoperative analgesia, even when administered at home. To optimize this technique, further studies are needed to help minimize the risk of side effects, improve techniques to locate the targeted nerve (stimulating catheters or ultrasound imaging) and choose less toxic drugs (levobupivacaine and ropivacaine) with more effective infusion regimens.

Ropivacaine: a review of its use in regional anaesthesia and acute pain management

Ropivacaine (Naropin) is the pure S(-)-enantiomer of propivacaine, and is a long-acting amide local anaesthetic agent, eliciting nerve block via reversible inhibition of sodium ion influx in nerve fibres. Ropivacaine is a well tolerated regional anaesthetic effective for surgical anaesthesia as well as the relief of postoperative and labour pain. The efficacy of ropivacaine is similar to that of bupivacaine and levobupivacaine for peripheral nerve blocks and, although it may be slightly less potent than bupivacaine when administered epidurally or intrathecally, equi-effective doses have been established. Clinically adequate doses of ropivacaine appear to be associated with a lower incidence or grade of motor block than bupivacaine. Thus ropivacaine, with its efficacy, lower propensity for motor block and reduced potential for CNS toxicity and cardiotoxicity, appears to be an important option for regional anaesthesia and for the management of postoperative and labour pain.

Stimulating Popliteal Catheters for Postoperative Analgesia After Hallux Valgus Repair

Stimulating catheters have been recently introduced in clinical practice. We assessed the efficacy of stimulating and nonstimulating catheter placement for pain control and local anesthetic requirements after hallux valgus repair with continuous sciatic popliteal nerve block in this comparative, randomized, blinded-to-observer study of 48 patients. A stimulating catheter was placed in groups S-125 and S-0625. The same catheter was inserted without stimulation in group NS-125. An infusion of 0.125% levobupivacaine was given in groups S-125 and NS-125, whereas 0.0625% levobupivacaine was used in group S-0625. All patients received an infusion of the test drug at a basal rate of 3 mL/h, with the possibility of an additional bolus of 3 mL every hour. Verbal analog scale (VAS) scores for pain were assessed between 6-8 h and between 19-23 h postoperatively. Multiple attempts were required for catheter insertion in all patients in groups S-125 and S-0625. Lower median (range) VAS scores for pain (0-100 points) were found in group S-125 at 6-8 h postoperatively when compared with groups S-0625 and NS-125: 5 (0-17.5) versus 60 (15-80) and 70 (25-80), respectively (P < 0.05); and lower VAS scores for pain were also found in group S-125 at 19-23 h when compared with group NS-125: 0 (0-0) and 7.5 (0-10), respectively (P < 0.05). Fewer patients required IV opioid analgesia in group S-125 than in groups S-0625 and NS-125: 0, 5, and 7 patients, respectively (P < 0.05). We conclude that efficacy in pain control was increased with stimulating catheter placement.

[Levobupivacaine for regional anesthesia. A systematic review]

Levobupivacaine [S(-)bupivacaine], the levorotatory S-enantiomer of racemic bupivacaine, is commercially available in the U.S. and in most European countries. We performed a systematic review (MEDLINE database) and identified 88 articles on the clinical application of levobupivacaine in more than 3,000 patients. The use of levobupivacaine is described for epidural, caudal, and spinal anesthesia, for peripheral nerve blocks, for ophthalmic and dental anesthesia, for different pediatric indications and for intravenous regional anesthesia. In these regional techniques, levobupivacaine was used for all common indications in a wide range of clinical settings. Epidural levobupivacaine was combined with fentanyl, morphine, sufentanil, epinephrine, and clonidine, spinal levobupivacaine was combined with sufentanil, fentanyl, and epinephrine. In most studies, levobupivacaine was compared to bupivacaine and/or ropivacaine.

Using Stimulating Catheters for Continuous Sciatic Nerve Block Shortens Onset Time of Surgical Block and Minimizes Postoperative Consumption of Pain Medication After Halux Valgus Repair as Compared with Conventional Nonstimulating Catheters

We prospectively tested the hypothesis that the use of a stimulating catheter improves the efficacy of continuous posterior popliteal sciatic nerve block in 100 randomized patients scheduled for elective orthopedic foot surgery. After eliciting a sciatic mediated muscular twitch at < or = 0.5 mA nerve stimulation output, the perineural catheter was advanced 2-4 cm beyond the tip of the introducer either blindly (Group C; n = 50) or stimulating via the catheter (Group S; n = 50). A bolus dose of 25 mL of 1.5% mepivacaine was followed by a postoperative patient-controlled infusion of 0.2% ropivacaine (basal infusion: 3 mL/h; incremental dose: 5 mL; lockout time: 30 min). Propacetamol 2 g IV was administered every 8 h, and opioid rescue analgesia was available if required. Catheter placement required 7 +/- 2 min in Group S and 5 +/- 2 min in Group C (P = 0.056). A significantly shorter onset time of both sensory and motor blocks was noted in Group S. No difference in quality of pain relief at rest and during motion was reported between the groups. Median (range) local anesthetic consumption during the first 48 h after surgery was 239 mL (175-519 mL) and 322 mL (184-508 mL) in Groups S and C, respectively (P = 0.002). Rescue opioid analgesia was required by 12 (25%) and 28 (58%) patients in Groups S and C, respectively (P = 0.002). We conclude that the use of a stimulating catheter results in shorter onset time of posterior popliteal sciatic nerve block, similar pain relief with reduced postoperative consumption of local anesthetic solution, and less rescue opioid consumption.

IMPLICATIONS

This prospective, randomized, blind investigation demonstrated that the use of a stimulating catheter for continuous posterior popliteal sciatic nerve block resulted in shorter onset time of sensory and motor blocks and less local anesthetic consumption and need for rescue pain medication after elective orthopedic foot surgery compared with blind catheter advancement.

Bupivacaine, levobupivacaine and ropivacaine: are they clinically different?

Two new, long-acting local anaesthetics have been developed after the evidence of bupivacaine-related severe toxicity: levobupivacaine and ropivacaine. Both these agents are pure left-isomers and, based on their three-dimensional structure, they have less toxic potential both on the central nervous system and on the heart. Several clinical studies have evaluated their toxicology and clinical profiles: theoretically and experimentally, some differences can be seen, but the reflections of these characteristics into clinical practice have not been evident. Evaluating randomised, controlled trials that have compared these three local anaesthetics, this chapter supports the evidence that both levobupivacaine and ropivacaine have a clinical profile similar to that of racemic bupivacaine, and that the minimal differences observed between the three agents are mainly related to the slightly different anaesthetic potency, with racemic bupivacaine>levobupivacaine>ropivacaine. However, the reduced toxic potential of the two pure left-isomers supports their use in those clinical situations in which the risk of systemic toxicity related to either overdosing or unwanted intravascular injection is high, such as during epidural or peripheral nerve blocks.