Route of Administration Affects Outcomes of Dexamethasone as an Adjuvant for Peripheral Nerve Blocks
With great interest, we have read the meta-analysis, “Perineural Versus Intravenous Dexamethasone as an Adjuvant for Peripheral Nerve Blocks: A Systematic Review and Meta-analysis,” authored by Chong et al,1 which was published recently in Regional Anesthesia and Pain Medicine. Chong et al1 reported that perineural (PN) dexamethasone provided longer duration of block than intravenous (IV) dexamethasone.1 In addition, patients receiving PN dexamethasone (the PN group) had less amount of 24-hour opioid consumption than patients receiving IV dexamethasone (the IV group).1 Judging from those data, one would expect that PN dexamethasone could provide better postoperative analgesia than IV dexamethasone in patients receiving peripheral nerve blocks. However, to our surprise, Chong et al1 reported that the PN and IV groups had similar postoperative pain scores. Of note, shortly after publication of the previously mentioned meta-analysis,1 a relevant double-blind randomized controlled trial authored by Sakae et al2 has been published. In contrast to the data reported by Chong et al,1 Sakae et al2 reported that the PN group had lower postoperative pain scores than did the IV group.
To elucidate further, we thus performed this meta-analysis and analyzed the data from all the studies included in the previously mentioned meta-analysis1 plus those reported by Sakae et al.2 Our data revealed that the duration of motor block (4.09 hours; 95% confidence interval [CI], 2.33–5.84; P < 0.001) and sensory block (2.74 hours; 95% CI, 0.58–4.90; P =0.01) in the PN group was significantly longer than that in the IV group. Our data also revealed that the pain scores at postoperative 12 hours (−0.75; 95% CI, −1.34 to −0.15; P = 0.01; Fig. 1A) and 24 hours (−1.15; 95% CI, −2.03 to −0.27; P = 0.01; Fig. 1B) in the PN group were significantly lower than those in the IV group.
Collectively, these data support the concept that PN dexamethasone can induce longer duration of nerve block and provide better postoperative analgesia than IV dexamethasone in patients receiving peripheral nerve blocks.