Effects of dexamethasone as a local anaesthetic adjuvant for brachial plexus block

[wtbcrna, MSN, DNP, CRNA]

Effects of dexamethasone as a local anaesthetic adjuvant for brachial plexus block: a systematic review and meta-analysis of randomized trials

[*=left]Abstract

"Background Brachial plexus nerve blocks (BPBs) have analgesic and opioid sparing benefits for upper extremity surgery. Single-injection techniques are limited by the pharmacological duration and therapeutic index of local anaesthetics (LAs). Continuous catheter techniques, while effective can present management challenges. Off-label use of perineural dexamethasone as an LA adjuvant has been utilized to prolong single-injection techniques. The objectives of this systematic review and meta-analysis are to assess the contemporary literature and quantify the effects of dexamethasone on BPB.

Methods The authors searched for randomized, placebo-controlled trials that compared BPB performed with LA alone with that performed with LA and perineural dexamethasone. Meta-analysis was performed using a random effects model with subgroup analysis stratified by LA (long vsintermediate). The primary outcome was duration of sensory block or analgesia; the secondary outcomes were motor block duration, opioid consumption, and BPB complications.

Results Nine trials (801 patients) were included with 393 patients receiving dexamethasone (4-10 mg). Dexamethasone prolonged the analgesic duration for long-acting LA from 730 to 1306 min [mean difference 576 min, 95% confidence interval (CI) 522-631] and for intermediate from 168 to 343 min (mean 175, 95% CI 73-277). Motor block was prolonged from 664 to 1102 min (mean 438, 95% CI 89-787). The most recent trial demonstrated equivalent prolongation with perineural or systemic administration of dexamethasone compared with placebo.

Conclusions Perineural administration of dexamethasone with LA prolongs BPB effects with no observed adverse events. The effects of systemic administration of dexamethasone on BPB must be investigated."

http://bja.oxfordjournals.org/content/early/2014/01/10/bja.aet417.short?rss=1

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for those of you hesitant to add steroids to your local anesthetic mixture, there's also some interesting evidence that 10 mg dexamethasone IV also prolongs the duration of ISB.

[h=1]Effect of dexamethasone on the duration of interscalene nerve blocks with ropivacaine or bupivacaine.[/h]Cummings KC 3rd1, Napierkowski DE, Parra-Sanchez I, Kurz A, Dalton JE, Brems JJ, Sessler DI.

[h=3]Author information[/h]

[h=3]Abstract[/h][h=4]BACKGROUND:[/h]Pain after shoulder surgery is often treated with interscalene nerve blocks. Single-injection blocks are effective, but time-limited. Adjuncts such as dexamethasone may help. We thus tested the hypothesis that adding dexamethasone significantly prolongs the duration of ropivacaine and bupivacaine analgesia and that the magnitude of the effect differs among the two local anaesthetics.

[h=4]METHODS:[/h]In a double-blinded trial utilizing single-injection interscalene block, patients were randomized to one of four groups: (i) ropivacaine: 0.5% ropivacaine; (ii) bupivacaine: 0.5% bupivacaine; (iii) ropivacaine and steroid: 0.5% ropivacaine mixed with dexamethasone 8 mg; and (iv) bupivacaine and steroid: 0.5% bupivacaine mixed with dexamethasone 8 mg. The primary outcome was time to first analgesic request after post-anaesthesia care unit discharge. The Kaplan-Meier survival density estimation and stratified Cox's proportional hazard regression were used to compare groups.

[h=4]RESULTS:[/h]Dexamethasone significantly prolonged the duration of analgesia of both ropivacaine [median (inter-quartile range) 11.8 (9.7, 13.8) vs 22.2 (18.0, 28.6) h, log-rank P

[h=4]CONCLUSIONS:[/h]Dexamethasone prolongs analgesia from interscalene blocks using ropivacaine or bupivacaine, with the effect being stronger with ropivacaine. However, block duration was longer with plain bupivacaine than ropivacaine. Thus, although dexamethasone prolonged the action of ropivacaine more than that of bupivacaine, the combined effect of dexamethasone and either drug produced nearly the same 22 h of analgesia.