Clonidine, but not Dexamethasone, Prolongs Ropivacaine-Induced Supraclavicular Brachial Plexus Nerve Block Duration

Effectiveness of Adding Dexamethasone to Lidocaine in Upper Limbs Nerve Blocks: A Systematic Review

PURPOSE

The use of perineural dexamethasone as an adjuvant drug to peripheral nerve block for postoperative pain is controversial. This systematic review aimed to determine the effectiveness of adding dexamethasone to lidocaine in upper limb nerve blocks.

DESIGN

Systematic review.

METHODS

This review used a comprehensive search strategy to retrieve relevant published randomized trial articles that fulfilled the inclusion and exclusion criteria, without time limits, (until December 2023) that assessed the effects of a combination of dexamethasone to lidocaine in upper limb nerve blocks. The databases used for the electronic literature search included PubMed, Embase, and Clinical Trials.gov, dbGaP, Cochrane library, and Google Scholar. There was no language, gender, or age limitation. This systematic review is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.

FINDINGS

Of 3,926 articles identified by the initial search, 8 studies that met our inclusion criteria. All articles were original research studies. All eight articles were clinical trials. The sample size in the selected studies ranged from 30 to 90 people. Studies demonstrated that combining dexamethasone with lidocaine significantly improved the quality of peripheral nerve blocks, increased the analgesia period, and decreased analgesic consumption.

CONCLUSIONS

This review supported that the combination of dexamethasone (dose of 4 to 10 mg) and lidocaine (concentration of 1.5% to 2%) for upper limb block was more effective and beneficial without any side effects. However, further clinical trials in this regard with more data, various regions, and larger sample sizes to support our hypothesis are recommended.

The effect of adjuvants added to local anaesthetics for single-injection upper extremity peripheral regional anaesthesia: A systematic review with network meta-analysis of randomised trials

BACKGROUND

Peripheral regional anaesthesia is frequently used for upper extremity surgery. To prolong the duration of analgesia, adjuvants can be added to single-injection local anaesthetics. Despite attempts to compare several adjuvants in pairwise meta-analyses, a comprehensive comparison is still missing.

OBJECTIVE

The objective of this network meta-analysis was to determine the effectiveness of adjuvants in upper extremity peripheral nerve blocks.

DESIGN

A systematic review of randomised controlled trials with network meta-analyses.

DATA SOURCES

A literature search in Embase, CENTRAL, MEDLINE and Web of Science was performed up to March 2023.

ELIGIBILITY CRITERIA

Randomised trials comparing different adjuvants injected perineurally in peripheral upper extremity nerve blocks were eligible. Frequentist network meta-analysis was conducted using a random effects model with physiological saline as the comparator. The primary endpoint was the ratio of means (ROM) of the duration of analgesia.

RESULTS

The review included 242 randomised controlled trials with a total of 17 391 patients. Twenty-eight adjuvants were compared in the largest networks. Most network estimations consisted of a high proportion of direct evidence. Fourteen adjuvants increased the duration of analgesia significantly by the following factors, ROM [95% confidence interval (CI)]: dexamethasone 1.95 (1.79 to 2.13), buprenorphine 1.83 (1.51 to 2.24), butorphanol 1.84 (1.41 to 2.39), potassium chloride 1.89 (1.15 to 3.11), dexmedetomidine 1.70 (1.59 to 1.81), sufentanil 1.70 (1.27 to 2.29), ketorolac 1.68 (1.24 to 2.27), midazolam 1.55 (1.24 to 1.94), tramadol 1.52 (1.32 to 1.75), nalbuphine 1.50 (1.30 to 1.72), morphine 1.43 (1.09 to 1.88), magnesium sulfate 1.42 (1.20 to 1.67), clonidine 1.36 (1.24 to 1.50) and fentanyl 1.23 (1.08 to 1.40). Inconsistency in network meta-analysis was substantial. Overall side effect rates were low with all adjuvants.

CONCLUSION

The best interventions to prolong the duration of analgesia were dexamethasone, followed by dexmedetomidine, opioids, electrolytes, ketorolac and midazolam. There are general concerns about the quality of underlying studies and the risk of publication bias.

TRIAL REGISTRATION

PROSPERO 2018 CRD42018115722.

Perineural and intravenous dexamethasone and dexmedetomidine: network meta-analysis of adjunctive effects on supraclavicular brachial plexus block

Both perineural and intravenous dexamethasone and dexmedetomidine are used as local anaesthetic adjuncts to enhance peripheral nerve block characteristics. However, the effects of dexamethasone and dexmedetomidine based on their administration routes have not been directly compared, and the relative extent to which each adjunct prolongs sensory blockade remains unclear. This network meta-analysis sought to compare and rank the effects of perineural and intravenous dexamethasone and dexmedetomidine as supraclavicular block adjuncts. We sought randomised trials investigating the effects of adding perineural and intravenous dexamethasone or dexmedetomidine to long-acting local anaesthetics on supraclavicular block characteristics, including time to block onset and durations of sensory, motor and analgesic blockade. Data were compared and ranked according to relative effectiveness for each outcome. Our primary outcome was sensory block duration, with a 2-h difference considered clinically important. We performed a frequentist analysis, using the GRADE framework to appraise evidence. One-hundred trials (5728 patients) were included. Expressed as mean (95%CI), the control group (local anaesthetic alone) had a duration of sensory block of 401 (366-435) min, motor block duration of 369 (330-408) min and analgesic duration of 435 (386-483) min. Compared with control, sensory block was prolonged most by intravenous dexamethasone [mean difference (95%CI) 477 (160-795) min], followed by perineural dexamethasone [411 (343-480) min] and perineural dexmedetomidine [284 (235-333) min]. Motor block was prolonged most by perineural dexamethasone [mean difference (95%CI) 294 (236-352) min], followed by intravenous dexamethasone [289 (129-448)min] and perineural dexmedetomidine [258 (212-304)min]. Analgesic duration was prolonged most by perineural dexamethasone [mean difference (95%CI) 518 (448-589) min], followed by intravenous dexamethasone [478 (277-679) min] and perineural dexmedetomidine [318 (266-371) min]. Intravenous dexmedetomidine did not prolong sensory, motor or analgesic block durations. No major network inconsistencies were found. The quality of evidence for intravenous dexamethasone, perineural dexamethasone and perineural dexmedetomidine for prolongation of supraclavicular sensory block duration was 'low', 'very low' and 'low', respectively. Regardless of route, dexamethasone as an adjunct prolonged the durations of sensory and analgesic blockade to a greater extent than dexmedetomidine. Differences in block characteristics between perineural and intravenous dexamethasone were not clinically important. Intravenous dexmedetomidine did not affect block characteristics.

Efficacy of Clonidine as an Additive on the Duration of Action of Brachial Plexus Block Performed Under Ultrasound and Nerve Locator Guidance: A Prospective Randomized Study

Background

Clonidine, an alpha₂ agonist, when added to local anesthetics in different regional and neuraxial blocks reduces the onset time, improves the efficacy, and increases the duration of postoperative analgesia.

Aims

This study evaluated the effect of bupivacaine clonidine combination in ultrasound and nerve locator-guided supraclavicular brachial plexus block for upper limb surgeries.

Settings and Design

This was a prospective, randomized, controlled, double-blind study carried out in a tertiary care center in South India on 50 patients with American Society of Anesthesiologists (ASA) physical status classes I and II undergoing elective upper limb surgery under supraclavicular brachial plexus block.

Materials and Methods

Eligible participants were randomized equally to either Group B who received 20 ml of bupivacaine and 7 mL of 2% lignocaine or Group C who received 20 ml of bupivacaine, 7 ml of 2% lignocaine, and 100 μg of clonidine.

Statistical Analysis

Continuous outcome variables were tested for statistical significance using Student's t-test, and Mann-Whitney U-test was used for outcomes that were nonnormally distributed. Categorical variables were compared using Fisher's exact test. P <0.05 was considered as statistically significant.

Results

The onset of sensory and motor blockade was significantly faster (P < 0.05) in Group C compared to Group B. The duration of sensory and motor block and the duration of analgesia were significantly longer in Group C (P < 0.001). The sedation in Group C patients was significantly more (P < 0.05) when compared to Group B, but none of the sedation scores exceeded 3 on the Ramsay sedation score. Hemodynamic parameters did not differ between groups (P > 0.05).

Conclusion

The inclusion of 100 μg of clonidine with bupivacaine in ultrasound-guided supraclavicular brachial plexus blocks prolongs both sensory and motor blockade. It also provides significant postoperative analgesia and mild sedation which is beneficial in the immediate stressful postoperative period.