Case report: Ropivacaine neurotoxicity at clinical doses in interscalene brachial plexus block

Peripheral Nerve Blocks Outperform General Anesthesia for Pain Control in Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-analysis

PURPOSE

The purpose of this review is to compare the effectiveness of different peripheral nerve blocks and general anesthesia (GA) in controlling postoperative pain after arthroscopic rotator cuff repair (ARCR).

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review was conducted for the period of January 1, 2005, to February 16, 2021, by searching the following databases: PubMed, Cochrane, Embase, and Arthroscopyjournal.org. The primary outcomes of interest included 1-hour, 24-hour, and 48-hour pain scores on a numeric rating scale or visual analog scale (VAS). Inclusion criteria were English language studies reporting on adults (≥18 years) undergoing ARCR with peripheral nerve blockade. To synthesize subjective pain score data at each evaluation time point across studies, we performed random-effects network meta-regression analyses accounting for baseline pain score as a covariate.

RESULTS

A total of 14 randomized controlled trials with 851 patients were included in the meta-analysis. Data from six different nerve block interventions, single-shot interscalene brachial plexus nerve block (s-ISB; 37.8% [322/851]), single-shot suprascapular nerve block (s-SSNB; 9.9% [84/851]), continuous ISB (c-ISB; 17.5% [149/851]), continuous SSNB (c-SSNB; 6.9% [59/851]), s-ISB combined with SSNB (s-ISB+SSNB; 5.8% [49/851]), s-SSNB combined with axillary nerve block (s-SSNB+ANB; 4.8% [41/851]), as well as GA (17.3% [147/851]) were included. Our meta-analysis demonstrated that c-ISB block had a significant reduction in pain score relative to GA at 1-hour postoperation (mean difference [MD]: -1.8; 95% credible interval [CrI] = -3.4, -.08). There were no significant differences in VAS pain scores relative to GA at 24 and 48 hours postoperatively. However, s-ISB+SSNB had a significant reduction in 48-hour pain score compared to s-ISB (MD = -1.07; 95% CrI = -1.92, -.22).

CONCLUSIONS

It remains unclear which peripheral nerve block strategy is optimal for ARCR. However, peripheral nerve blocks are highly effective at attenuating postoperative ARCR pain and should be more widely considered as an alternative over general anesthesia alone.

LEVEL OF EVIDENCE

Level II Systematic review and meta-analysis of Level I and II studies.

Multiple myeloma and malignant lesions: a potential risk factor for local anesthetic systemic toxicity

BACKGROUND

Multiple myeloma is a cancer of plasma cells that often leads to complications including osteolytic bone lesions, nephropathy and neuropathy. Multiple myeloma is only one etiology of many cancer pain conditions that may necessitate interventional pain treatment when refractory to multimodal medications. Notably, local anesthetic systemic toxicity is a rare but life-threatening complication of local anesthetic administered for these interventions.

CASE PRESENTATION

A 50-60-year-old woman presented with multiple myeloma complicated by chronic bone pain and in an acute pain crisis. A fluoroscopic-guided L4-5 epidural catheter was placed with clinical doses of bupivacaine for comfort to undergo MRI of the spine. Soon after, she became tachycardic, tachypneic and hypoxic requiring non-invasive positive pressure airway support. As this respiratory distress was attributed to a large pleural effusion, a pigtail catheter was inserted in the intensive care unit with submaximally dosed lidocaine infiltration. She then developed a left bundle branch block followed by cardiovascular collapse minimally responsive to high-dose inotrope and vasopressor support. Lipid emulsion was started with dramatic therapeutic response and recovery to baseline. A CT of the thoracolumbar spine showed worsening extensive lytic lesions throughout all vertebral bodies and ribs from diffuse myeloma.

CONCLUSIONS

Patients with oncologic lesions focal to the thoracolumbar spine may be at higher risk for local anesthetic systemic toxicity from palliative epidurals due to increased cancer-related angiogenesis. Likewise, local anesthetic infiltration for procedures near any malignant sites could have a similar risk and may require lower initial fractionated dosages with increased vigilance.

Local Anesthetic-Induced Central Nervous System Toxicity during Interscalene Brachial Plexus Block: A Case Series Study of Three Patients

Local anesthetics are commonly administered by nuchal infiltration to provide a temporary interscalene brachial plexus block (ISB) in a surgical setting. Although less commonly reported, local anesthetics can induce central nervous system toxicity. In this case study, we present three patients with acute central nervous system toxicity induced by local anesthetics applied during ISB with emphasis on neurological symptoms, key neuroradiological findings and functional outcome. Medical history, clinical and imaging findings, and outcome of three patients with local anesthetic-induced toxic left hemisphere syndrome during left ISB were analyzed. All patients were admitted to our neurological intensive care unit between November 2016 and September 2019. All three patients presented in poor clinical condition with impaired consciousness and left hemisphere syndrome. Electroencephalography revealed slow wave activity in the affected hemisphere of all patients. Seizure activity with progression to status epilepticus was observed in one patient. In two out of three patients, cortical FLAIR hyperintensities and restricted diffusion in the territory of the left internal carotid artery were observed in magnetic resonance imaging. Assessment of neurological severity scores revealed spontaneous partial reversibility of neurological symptoms. Local anesthetic-induced CNS toxicity during ISB can lead to severe neurological impairment and anatomically variable cerebral lesions.

Ropivacaine induced systemic toxicity in a patient with phacomatosis pigmentokeratotica

Calculation of the maximum recommended dose of local anesthetic minimizes the risk of Local Anesthetic Systemic Toxicity (LAST) when administrating multiple blocks for lower limb surgeries. Ropivacaine is the preferred local anesthetic as it is less lipophilic than bupivacaine and thus results in less central nervous system (CNS) and cardiovascular toxicity. The presence of developmental, congenital, and metabolic disorders mandates an extracautious approach in the administration of large volume of Local anaesthesia (LA) as the vascularity of the limb, levels of alpha-1-acid glycoprotein, and sensitivity of the sodium channels may be altered. This case report highlights successful resuscitation of a patient with Phacomatosis pigmentokeratotica after the development of CNS toxicity secondary to the administration of ropivacaine in ultrasound-guided combined lumbar plexus and sciatic nerve block. We identified some high risk patient profiles which should be vigilantly monitored to minimize the incidence of LAST.

Ultrasound-Guided Interscalene Brachial Plexus Block for Pathological Humerus Fracture due to Multiple Myeloma with Systemic Manifestation: Useful Option for Management in Low-Income Countries

Anesthetic management of pathological fracture due to multiple myeloma with systemic manifestation poses a perioperative challenge especially in low-resource setups like Nepal. Regional anesthesia using ultrasound-guided block can improve the accuracy, reduce complications, and improve overall perioperative management of pathological fractures due to malignancy with systemic spread in resource-deprived setups. We present a case of a 53-year-old lady with pathological fracture of left humerus shaft, a diagnosed case of multiple myeloma with compression fracture of multiple lumbar spine with chest wall metastasis with resolving acute kidney injury with chest infections. Ultrasound-guided interscalene brachial plexus block with sedation was done for open reduction internal fixation of humerus shaft fracture taking in consideration the overall high perioperative risk of patient. Intraoperative hemodynamic was uneventful, with no neurological sequelae and good recovery status perioperatively. Ultrasound-guided interscalene brachial plexus block if done cautiously can be a very useful alternative technique for better perioperative outcome in patients with malignancy with systemic spread in areas where expertise is scarce and resource is limited.

Effects of local dexmedetomidine administration on the neurotoxicity of ropivacaine for sciatic nerve block in rats

Dexmedetomidine, used as an adjuvant to local anesthetics (LAs), may prolong the duration of peripheral nerve block. However, the effect of dexmedetomidine on the neurotoxicity of LAs is not completely understood. The present study was designed to investigate the efficacy of two doses of dexmedetomidine as an adjuvant to ropivacaine and its protective effect against the neurotoxicity of LAs. Paw withdrawal thermal latency testing was used to detect the sensory blockade. Extensor postural thrust testing was used to detect the motor blockade. The results demonstrated that the addition of dexmedetomidine to ropivacaine prolonged the duration of sensory and motor blockade in a dose-dependent manner compared with ropivacaine alone. TUNEL staining was performed to examine apoptosis. Western blotting was used to detect the Cleaved caspase-3 expression levels. The results showed that the addition of dexmedetomidine to ropivacaine decreased the rate of apoptosis and caspase-3 expression levels in a dose-dependent manner compared with ropivacaine alone (P<0.05). In addition, the rate of apoptosis and caspase-3 expression levels were significantly lower in the high-dose dexmedetomidine group compared with the low-dose dexmedetomidine group (P<0.05). The results suggested that the addition of dexmedetomidine to ropivacaine for sciatic nerve block in rats not only prolonged the duration of sensory and motor block of the sciatic nerve, but also markedly alleviated ropivacaine-induced neurotoxicity by decreasing caspase-3-dependent sciatic nerve cell apoptosis. Furthermore, the present study indicated that dexmedetomidine was more effective at a dose of 20 µg/kg compared with 6 µg/kg.

Pharmacokinetics of ropivacaine in elderly patients receiving fascia iliaca compartment block

Local anesthetic of ropivacaine was demonstrated to reduce the postoperative pain in elderly patients. This study investigated the pharmacokinetics of ropivacaine at different concentrations in elderly patients subjected to fascia iliaca compartment block. Forty patients with femoral neck fracture at American Society of Anesthesiologists (ASA) I-II status, undergoing fascia iliaca compartment block (FICB) were randomized to two groups receiving 0.7 ml/kg of solution containing 0.375% ropivacaine (group L) or 0.5% ropivacaine (group H). Samples of venous blood were obtained immediately at different time points after FICB, and the total and free plasma concentrations of ropivacaine were measured by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Statistical analysis was carried out using a pharmacokinetic calculation program (DAS 3.0). Visual Analogue Scale (VAS) scores were significantly decreased after FICB in both groups, and VAS score in group H was lower compared with group L. The total maximum plasma concentration (C_max) and the free C_max of ropivacaine in group H was higher than that in group L (P<0.05). The decrease of the total and free plasma concentration was operation time-dependent. Neither group showed signs of central nervous system and circulatory system toxicity. On the basis of these results, the concentrations of 0.375 and 0.5% ropivacaine held an efficiently analgesic effect for FICB, suggesting that ropivacaine can be employed in analgesic therapy. However, both concentrations have a potentially theoretical risk of local anesthetics poisoning, suggesting that a lower concentration may be a safer option for a single large volume of FICB.

The role of DRP1 in ropivacaine-induced mitochondrial dysfunction and neurotoxicity

Ropivacaine is a commonly used local anaesthetic, but its side effects remain largely unknown. In the present study, we investigated the side effects of ropivacaine in human neuronal SH-5Y5Y cells. We show that 0.5% and 1% ropivacaine could cause fission-like mitochondrial morphological changes. Ropivacaine exclusively induces mitochondrial fission protein DRP1, generation of ROS and causes mitochondrial dysfunction including decreasing mitochondrial membrane potential, the activity of cytochrome C oxidase and ATP production. The side effects of ropivacaine appear to be dependent on DRP1 expression as silencing of DRP1 in neuronal cells abolishes ropivacaine-induced morphological changes and mitochondrial dysfunction. Silencing of DRP1 prevents ropivacaine-induced cellular LDH release and cell death. Moreover, DRP1-deficient neuronal cells are resistant to ropivacaine-induced apoptosis and silencing of DRP1 rescues the activity of cytochrome C oxidase and cellular ATP production. Collectively, our data indicate that imbalances in mitochondrial dynamics, mitochondrial dysfunction and cell death resulting from ropivacaine are all dependent on DRP1 expression. Our study provides valuable data to assess the safety of ropivacaine.

Ropivacaine impairs mitochondrial biogenesis by reducing PGC-1α

Ropivacaine is one of the commonly used local anesthetics in medical and dental care. However, preclinical and observational studies indicate that ropivacaine could have substantial side effects including neurotoxicity, which has raised concern regarding the safety of this drug. In the present study, we investigated the effects of clinically relevant doses of ropivacaine on mitochondrial biogenesis and function in neuronal cells. Our data indicate that exposure to ropivacaine leads to reduced expression of the major mitochondrial regulator PGC-1α and its downstream transcription factors NRF1 and TFAM. Ropivacaine treatment induces impairment of mitochondrial biogenesis by reducing mitochondrial mass, the ratio of mtDNA to nDNA (mtDNA/nDNA), cytochrome C oxidase activity, and COX-1 expression. Additionally, treatment with ropivacaine causes "loss of mitochondrial function" by impairing the mitochondrial respiratory rate and ATP production. Mechanistically, the reduction of PGC-1α caused by ropivacaine exposure requires inactivation of CREB, while re-introduction of PGC-1α completely rescues ropivacaine-induced mitochondrial abnormalities. In summary, our results provide supporting evidence that mitochondrial impairment is a key event in ropivacaine-mediated neurotoxicity, and the reduction of PGC-1α and its downstream signals are likely the molecular mechanism behind its cellular toxicity.

CaMK II γ down regulation protects dorsal root ganglion neurons from ropivacaine hydrochloride neurotoxicity

T-type calcium channels are intimately involved in the local anesthetics neurotoxicity. Does CaMKIIγ regulate T-type calcium currents in local anesthetics neurotoxicity? This study generated pAd-CaMKIIγ and pAd-shRNA adenovirus vectors to up- and down-regulate CaMKIIγ mRNA expression in dorsal root ganglion neurons (DRG). Normal DRG (Normal group), empty vector DRG (Empty vector group), pAd-CaMKIIγ DRG (pAd-CaMKIIγ group) and pAd-shRNA DRG (pAd-shRNA group) were treated or untreated with 3 mM ropivacaine hydrochloride for 4 h. Cell viability, apoptosis rate, CaMKIIγ, pCaMKIIγ, Cav3.2, and Cav3.3 expression were detected. Ultrastructural changes in DRG were observed under a transmission electron microscope. The results demonstrated that the cell viability of DRG treated with ropivacaine hydrochloride decreased markedly, the apoptosis rate, CaMKIIγ, pCaMKIIγ, Cav3.2, Cav3.3 expression increased significantly. CaMKIIγ up-regulation aggravated ropivacaine hydrochloride-induced cell damage and increased Cav3.2 and Cav3.3 expression. In conclusion, CaMKIIγ regulated Cav3.2 and Cav3.3 expression in DRG, which was involved with ropivacaine hydrochloride-induced cell injury.

Incidence of cardiovascular complications in knee arthroplasty patients before and after implementation of a ropivacaine local infiltration analgesia protocol: A retrospective study

BACKGROUND

Local infiltration analgesia (LIA) during total knee arthroplasty has been shown to give statistically significant reduction in post-operative pain. The effects of using high volumes of ropivacaine combined with adrenaline as LIA on cardiovascular parameters in knee replacement have not been described before. The objective of this study was to investigate the cardiovascular safety of ropivacaine as part of high volume local infiltration analgesia (LIA) in total knee replacement surgery.

METHODS

This is a retrospective observational comparative cohort study conducted in two independent cohorts, one treated without and one treated with a local infiltration analgesia protocol, containing a total of 744 patients with a mean age of 68years (42 to 89) and 68years (21 to 88) respectively with a follow-up of 12months.

RESULTS

No statistical difference in bradycardia during surgery, post-operative cardiovascular complications, and mortality was found after use of LIA. A statistically significant lower incidence of hypotension was found in the LIA group (P<0.01). This result has to be interpreted with care, due to the use of adrenaline in the LIA mixture, which could mask possible hypotension. No statistical difference was found in the occurrence of hypertension or tachycardia, despite the addition of adrenaline to the LIA mixture. No difference in mortality was found between the two groups (P=0.11).

CONCLUSION

These results show safe use of high volume ropivacaine with adrenaline as local infiltration analgesia during total knee replacement surgery.

A Comparison of Differences Between the Systemic Pharmacokinetics of Levobupivacaine and Ropivacaine During Continuous Epidural Infusion: A Prospective, Randomized, Multicenter, Double-Blind Controlled Trial

BACKGROUND:

Epidural infusion of levobupivacaine and ropivacaine provides adequate postoperative pain management by minimizing side effects related to IV opioids and improving patient outcome. The safety profile of different drugs can be better estimated by comparing their pharmacokinetic profiles than by considering their objective side effects. Because levobupivacaine and ropivacaine have different pharmacokinetic properties, our aim was to investigate whether there is a difference in the pharmacokinetic variability of the 2 drugs in a homogeneous population undergoing continuous epidural infusion. This double-blind, multicenter, randomized, controlled trial study was designed to compare the pharmacokinetics of continuous thoracic epidural infusion of levobupivacaine 0.125% or ropivacaine 0.2% for postoperative pain management in adult patients who had undergone major abdominal, urological, or gynecological surgery. This study is focused on the evaluation of the coefficient of variation (CV) to assess the equivalence in the systemic exposure and interindividual variability between levobupivacaine and ropivacaine and, therefore, the possible differences in the predictability of the plasmatic concentrations of the 2 drugs during thoracic epidural infusion.

METHODS:

One hundred eighty-one adults undergoing major abdominal surgery were enrolled in the study. Patients were randomized to receive an epidural infusion of levobupivacaine 0.125% + sufentanil 0.75 μg/mL or of ropivacaine 0.2% + sufentanil 0.75 μg/mL at 5 mL/h for 48 hours. The primary end point of this study was to analyze the variability of plasma concentration of levobupivacaine and ropivacaine via an area under the curve within a range of 15% of the CV during 48 hours of continuous epidural infusion. The CV shows how the concentration values of local anesthetics are scattered around the median concentration value, thus indicating the extent to which plasma concentration is predictable during infusion. Secondary end points were to assess the pharmacologic profile of the local anesthetics used in the study, including an analysis of mean peak plasma concentrations, and also to assess plasma clearance, side effects, pain intensity (measured with a verbal numeric ranging score, i.e., static Numeric Rating Scale [NRS] and dynamic NRS]), and the need for rescue doses.

RESULTS:

The comparison between the 2 CVs showed no statistical difference: the difference between area under the curve was within the range of 15%. The CV was 0.54 for levobupivacaine and 0.51 for ropivacaine (P = 0.725). The plasma concentrations of ropivacaine approached the C_max significantly faster than those of levobupivacaine. Clearance of ropivacaine decreases with increasing patient age. There were no significant differences in NRS, dynamic NRS scores, the number of rescue doses, or in side effects between groups.

CONCLUSIONS:

Considering the CV, the interindividual variability of plasma concentration for levobupivacaine and ropivacaine is equivalent after thoracic epidural infusion in adults. We found a reduction in clearance of ropivacaine depending on patient age, but this finding could be the result of some limitations of our study. The steady-state concentration was not reached during the 48-hour infusion and the behavior of plasma concentrations of ropivacaine and levobupivacaine during continuous infusions lasting more than 48 hours remains to be investigated, because they could reach toxic levels. Finally, no differences in the clinical efficacy or in the incidence of adverse effects between groups were found for either local anesthetic.

Published ahead of print May 14, 2015

Infusion Methods for Continuous Interscalene Brachial Plexus Block for Postoperative Pain Control after Arthroscopic Rotator Cuff Repair

Background

Infusion methods during regional analgesia using perineural catheters may influence the quality of postoperative analgesia. This study was conducted to compare the effects of combined or bolus-only infusion of 0.2% ropivacaine on the postoperative analgesia in interscalene brachial plexus block (ISBPB) with perineural catheterization.

Methods

Patients scheduled for arthroscopic rotator cuff repair were divided into two groups, one that would receive a combined infusion (group C, n = 32), and one that would receive intermittent infusion (group I, n = 32). A perineural catheter was inserted into the interscalene brachial plexus (ISBP) using ultrasound (US) and nerve stimulation, and 10 ml of 0.2% ropivacaine was administered. After the operation, group C received a continuous infusion of 4 ml/h, and a 4 ml bolus with a lockout interval of 60 min. Group I received only a 4 ml bolus, and the lockout interval was 30 min. Postoperative pain by the numeric rating scale (NRS) and the forearm muscle tone by the manual muscle test (MMT) were checked and evaluated at the following timepoints: preoperative, and postoperative 1, 4, 12, 24, 36, and 48 h. Supplemental opioid requirements, total consumed dose of local anesthetic, and adverse effects were compared between the two groups.

Results

Sixty-four patients completed the study and the postoperative values such as operation time, time to discharge, and operation site were comparable. There were no differences in NRS scores and supplemental opioid requirements between the two groups. The MMT scores of group I at 4 and 12 h after surgery were significantly higher than those of group C (P < 0.05). The total consumed dose of local anesthetic was significantly lower in group I than in group C (P < 0.05). The adverse effects were not different between the groups.

Conclusions

The bolus-only administration of 0.2% ropivacaine provided a similar analgesic effect with a lower total volume of local anesthetic and decreased motor weakness compared to combined infusion. Therefore, bolus-only administration is an effective postoperative analgesic method in ISBPB with perineural catheterization after rotator cuff repair.

Ropivacaine pharmacokinetics after local infiltration analgesia in hip arthroplasty

In this study, we determined the plasma concentration of ropivacaine by liquid chromatography-mass spectrometry for 30 hours after local infiltration analgesia in 15 patients with elective hip arthroplasty. The 95% upper prediction bound of maximal unbound plasma concentration of ropivacaine was 0.032 mg/L. Side effects sufficient to stop an IV infusion have been reported at arterial concentrations of 0.34 to 0.85 mg/L. Alpha-1-acid glycoprotein did not correlate with the fraction of unbound ropivacaine during the first 24 hours after local infiltration analgesia. No signs or symptoms of systemic local anesthetic toxicity were observed. The Clopper-Pearson 95% upper confidence limit for adverse signs was 0.218.

Application of echogenic technology for catheters used in ultrasound-guided continuous peripheral nerve blocks

Limited data exist regarding the echogenicity of perineural catheters, but visualization is crucial to ensure accurate placement and efficacy of the subsequent local anesthetic infusion. The objective of this study was to determine the comparative echogenicity of various regional anesthesia catheters. In an in vitro porcine-bovine model, we compared the echogenic qualities of 3 commercially available regional anesthesia catheters and 1 catheter under development to optimize echogenicity. Outcomes included visual echogenicity ranking, image quality, and scanning time, as assessed by 2 blinded investigators. The experimental catheter was found to be more echogenic than 2 of the 3 comparators.

Feasibility of Early and Repeated Low-dose Interscalene Brachial Plexus Block for Residual Pain in Acute Cervical Radiculopathy Treated with NSAIDS

Background

To improve residual pain management in acute cervical radiculopathy treated with NSAIDs, the feasibility of early and repeated low-dose interscalene brachial plexus block (IS-BPB) needs to be assessed.

Methods

This was a prospective study on patients receiving NSAIDs (loxoprofen) for cervical radiculopathy of ≤ 2-week onset. Pain was assessed using the visual analogue scale (VAS). A low-dose ultrasonography (USG)-guided IS-BPB (dexamethasone [1.65 mg; 0.5 ml] and mepivacaine [1%; 3.0 ml]) was performed at baseline and weekly thereafter for 4 weeks in an outpatient setting for the intervention group. All patients were evaluated using a visual satisfaction score (VSS) at week 4. Patients with baseline VAS scores < 70 (mild to moderate pain; MM group) and ≥ 70 (severe pain; SE group) were compared to the controls receiving NSAIDs.

Results

A total of 316 IS-BPBs were performed in the intervention group. There was a significant difference in the decline in the VAS from week 0 to week 3 in the MM and SE groups (P < 0.05); however, from week 3 to week 4, the therapeutic effect exhibited no significant difference. Thirteen patients at week 2 (15.5%; MM: 27.7%; SE: 0%), 43 at week 3 (51.2%; MM: 83.0%; SE: 10.8%), and 47 at week 4 (56.0%; MM: 85.1%; SE: 18.9%) achieved a VAS score of ≤ 20. Patient satisfaction was high, and the decrease in VAS scores in both groups was significant (P < 0.05) compared to the controls.

Conclusions

Weekly, low-dose, USG-guided IS-BPB can be implemented for early pain relief in acute cervical radiculopathy, with high patient satisfaction.

Incidence of failure of continuous peripheral nerve catheters for postoperative analgesia in upper extremity surgery

PURPOSE

To explore the incidence of failure of continuous peripheral nerve blockade (CPNB) after upper extremity operations.

METHODS

Patient data regarding postoperative CPNB were retrospectively obtained from our institution's regional anesthesia database. Documented information on the first postoperative day included pain assessment ratings (numerical verbal pain scale, patient-reported breakthrough pain upon perceived return of sensation, appearance of the catheter site, complications, time of return of sensation, day of return of sensation, residual blockade, patient satisfaction with the block, and whether patient would receive the block again).

RESULTS

A total of 207 patients received CPNB for postoperative analgesia. The failure rate on the first postoperative day for infraclavicular (133 patients) and supraclavicular (58 patients) CPNB was 19% and 26%, respectively. Interscalene CPNB (16 patients) yielded 3 incidences of failure. No significant difference was found between supraclavicular and infraclavicular block techniques. In addition, no significant differences were found between the incidences of CPNB failures with potentially more painful surgeries involving bone compared with potentially less painful soft tissue procedures.

CONCLUSIONS

The CPNB technique used for hand surgery postoperative analgesia was associated with nontrivial failure rates. The potential of CPNB failure and resulting breakthrough pain upon recovery from the primary nerve block is important to help establish patient expectations.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Low-dose ropivacaine for supraclavicular brachial plexus block combined with general anesthesia for successful postoperative analgesia: A case series

Background:

Ropivacaine, a long-acting local anesthetic agent, has been used for postoperative analgesia in brachial plexus block (BPB) at high doses. However, use of lower doses would reduce the occurrence of adverse effects.

Methods:

We applied BPB with low-dose ropivacaine (10 mL of 0.375% ropivacaine) after induction of general anesthesia for surgery of the upper extremities in 62 patients at our hospital. Ropivacaine was administered via a fluoroscopy-guided supraclavicular method. Analgesic effects during surgery, visual analog scale pain scores, skin sensation, muscle strength, and postoperative patient satisfaction indices were evaluated.

Results:

Fifty-six patients (90.3%) did not require supplemental analgesics during surgery. The remaining six patients were administered fentanyl due to the insufficient analgesic effects of the nerve block. Some adverse effects, including numbness and delayed motor and sensory recovery of the upper extremities, were observed. The mean postoperative patient-evaluated visual satisfaction scale was 94.1.

Conclusions:

Our results suggest that low-dose ropivacaine is clinically acceptable for BPB under general anesthesia.

The role of continuous peripheral nerve blocks

A continuous peripheral nerve block (cPNB) is provided in the hospital and ambulatory setting. The most common use of CPNBs is in the peri- and postoperative period but different indications have been described like the treatment of chronic pain such as cancer-induced pain, complex regional pain syndrome or phantom limb pain. The documented benefits strongly depend on the analgesia quality and include decreasing baseline/dynamic pain, reducing additional analgesic requirements, decrease of postoperative joint inflammation and inflammatory markers, sleep disturbances and opioid-related side effects, increase of patient satisfaction and ambulation/functioning improvement, an accelerated resumption of passive joint range-of-motion, reducing time until discharge readiness, decrease in blood loss/blood transfusions, potential reduction of the incidence of postsurgical chronic pain and reduction of costs. Evidence deriving from randomized controlled trials suggests that in some situations there are also prolonged benefits of regional anesthesia after catheter removal in addition to the immediate postoperative effects. Unfortunately, there are only few data demonstrating benefits after catheter removal and the evidence of medium- or long-term improvements in health-related quality of life measures is still lacking. This review will give an overview of the advantages and adverse effects of cPNBs.

Ultrasound brachial plexus anesthesia and analgesia for upper extremity surgery: essentials of our current understanding, 2011

PURPOSE OF REVIEW

Ultrasound-guidance is gaining tremendous popularity. There is growing evidence of value with emphasis on clinical relevance, but can ultrasound-guidance scientifically warrant changing the practice of upper extremity regional? The literature is searched to describe findings where ultrasound may reduce complication rates, reduce block performance times, and improve block efficacy and quality.

RECENT FINDINGS

Ultrasound examination identified variations in anatomical positioning of C5-C7 roots in approximately half of all patients despite no deleterious effects on block efficacy. Anesthetic volumes in brachial plexus blockade may be reduced without compromise of effectiveness. However, even with reduced volumes injected into the interscalene space, respiratory compromise from effect(s) on the phrenic nerve may result in hemi-diaphragmatic paresis. Ultrasound-guidance may reduce discomfort during axillary block placement compared with neurostimulation or parasthesia. Nerve catheters may be highly effective and provide prolonged analgesia compared with single-shot injections. Infraclavicular catheters result in improved analgesia compared with supraclavicular catheters and multiple injections of local provide no advantage over single-shot infraclavicular blockade. Dexamethasone combined with local may extend analgesia following a single-injection interscalene or supraclavicular block. During interscalene blockade, intraepineurial injections may occur, but incidence of nerve injury remains low. Therefore, debate continues about intraepineurial injections.

SUMMARY

Intraepineurial injection requires additional investigation. Conclusions have suggested reducing typical volumes (40  ml) of local with ultrasound-directed upper extremity blockade. Increased use of perineural catheters is being advocated for prolonged analgesia, but risk-to-benefit consequences need to always be considered.

Delayed appearance of hypaesthesia and paralysis after femoral nerve block

We report on a female patient who underwent an arthroscopy of the right knee and was given a continuous femoral nerve block catheter. The postoperative course was initially unremarkable, but when postoperative mobilisation was commenced, 18 hours after removal of the catheter, the patient noticed paralysis and hypaesthesia. Examination confirmed the diagnosis of femoral nerve dysfunction. Colour duplex sonography of the femoral artery and computed tomography of the lumbar spine and pelvis yielded no pathological findings. Overnight the neurological deficits decreased without therapy and were finally no longer detectable. We speculate that during the administration of the local anaesthetic a depot formed, localised in the medial femoral intermuscular septa, which was leaked after first mobilisation. To our knowledge no similar case has been published up to now. We conclude that patients who are treated with a nerve block should be informed and physician should be aware that delayed neurological deficits are possible.

Clinical presentation of local anesthetic systemic toxicity: a review of published cases, 1979 to 2009

The classic description of local anesthetic systemic toxicity (LAST) generally described in textbooks includes a series of progressively worsening neurologic symptoms and signs occurring shortly after the injection of local anesthetic and paralleling progressive increases in blood local anesthetic concentration, culminating in seizures and coma. In extreme cases, signs of hemodynamic instability follow and can lead to cardiovascular collapse. To characterize the clinical spectrum of LAST and compare it to the classic picture described above, we reviewed published reports of LAST during a 30-year period from 1979 to 2009. Ninety-three cases were identified and analyzed with respect to onset of toxicity and the spectrum of signs and symptoms. Sixty percent of cases followed the classic pattern of presentation. However, in the remainder of cases, symptoms were substantially delayed after the injection of local anesthetic, or involved only signs of cardiovascular compromise, with no evidence of central nervous system toxicity. Although information gained from retrospective case review cannot establish incidence, outcomes, or comparative efficacies of treatment, it can improve awareness of the clinical spectrum of LAST and, theoretically, the diagnosis and treatment of affected patients. The analytic limitations of our method make a strong case for developing a prospective, global registry of LAST as a robust alternative for educating practitioners and optimizing management of LAST.

Regional Anaesthesia for Bilateral Upper Limb Surgery: A Review of Challenges and Solutions

Regional anaesthesia for bilateral upper limb surgery can be challenging, yet surgeons are becoming increasingly interested in performing bilateral procedures at the same operation. Anaesthetists have traditionally avoided bilateral brachial plexus block due to concerns about local anaesthetic toxicity, phrenic nerve block and pneumothorax. We discuss these three concerns and review whether advances in ultrasound guidance and nerve catheter techniques should make us reconsider our options. A search of Medline and EMBASE from 1966 to January 2009 was conducted using multiple search terms to identify techniques of providing anaesthesia or analgesia for bilateral upper limb surgery and potential side-effects. Ultrasound imaging and nerve catheter techniques have led to a reduction in dose requirements for effective blocks without side-effects. Effective regional anaesthesia can be performed for bilateral surgery while remaining within recommended safe dose limits. Spacing blocks apart in time can further reduce potential toxicity issues, such that peak absorption rates for each block do not coincide. Since phrenic nerve block remains an issue even with low doses of local anaesthesia, bilateral interscalene blocks are still not recommended. Peripheral nerve blocks have excellent safety profiles and are ideal for ultrasound guidance. Regional anaesthesia can be a suitable option for bilateral upper limb surgery.

Effect of local anaesthetic volume (20 vs 5 ml) on the efficacy and respiratory consequences of ultrasound-guided interscalene brachial plexus block

BACKGROUND

Interscalene brachial plexus block (ISBPB) is an effective nerve block for shoulder surgery. However, a 100% incidence of phrenic nerve palsy limits the application of ISBPB for patients with limited pulmonary reserve. We examined the incidence of phrenic nerve palsy with a low-volume ISBPB compared with a standard-volume technique both guided by ultrasound.

METHODS

Forty patients undergoing shoulder surgery were randomized to receive an ultrasound-guided ISBPB of either 5 or 20 ml ropivacaine 0.5%. General anaesthesia was standardized. Both groups were assessed for respiratory function by sonographic diaphragmatic assessment and spirometry before and after receiving ISBPB, and after surgery. Motor and sensory block, pain, sleep quality, and analgesic consumption were additional outcomes. Statistical comparison of continuous variables was analysed using one-way analysis of variance and Student's t-test. Non-continuous variables were analysed using chi(2) tests. Statistical significance was assumed at P<0.05.

RESULTS

The incidence of diaphragmatic paralysis was significantly lower in the low-volume group compared with the standard-volume group (45% vs 100%). Reduction in forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow at 30 min after the block was also significantly less in the low-volume group. In addition, there was a significantly greater decrease in postoperative oxygen saturation in the standard-volume group (-5.85 vs -1.50, P=0.004) after surgery. There were no significant differences in pain scores, sleep quality, and total morphine consumption up to 24 h after surgery.

CONCLUSIONS

The use of low-volume ultrasound-guided ISBPB is associated with fewer respiratory and other complications with no change in postoperative analgesia compared with the standard-volume technique.

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