Synergistic effect of IV dexamethasone and IV dexmedetomidine on the postoperative pain control after interscalene brachial plexus block for arthroscopic shoulder surgery: A randomized controlled trial
RyungA Kang, Ji Seon Jeong, Ju Hyun Lee, Do Yeon. Kim, Duck Hwan Choi, and Justin Sangwook Ko
Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University school of Medicine, Seoul, Korea.
Background and Objectives: Intravenous (IV) administration of dexamethasone or dexmedetomidine is reported to prolong the duration of analgesia after single-shot interscalene brachial plexus block (ISBPB). However, the effect of coadministration of these agents on the duration of analgesia has not been evaluated. Therefore, herein, we aimed to evaluate the difference in time to the first rescue analgesic request in patients receiving coadministration of IV dexamethasone and dexmedetomidine versus the ones receiving IV dexamethasone only after single-shot ISBPB for arthroscopic shoulder surgery.
Methods: After approval by the Samsung Medical Center Research Ethics Board (identifier 2017-04-009), this trial was prospectively registered with the Clinical Trial Registry of Korea (KCT 0002119). We enrolled sixty-six patients scheduled for arthroscopic shoulder surgery with ISBPB with 15 ml of 0.5 % ropivacaine with 1:200,000 epinephrine and were randomly assigned to one of three groups: (1) IV normal saline (control, n=22), (2) IV dexamethasone 0.11 mg.kg-1(D1, n=22), (3) IV dexamethasone 0.11 mg.kg-1 and IV dexmedetomidine 1.0 μg.kg-1(D2, n=22). The primary outcome was the time to first rescue analgesic request. Secondary outcomes included postoperative cumulative opioid consumption, pain scores, sleep disturbance, blood glucose levels, and complications.
Results: The median (interquartile range) time to first rescue analgesic request was significantly longer for the D2 group (66.3 h [23.3 to 72]) compared with control (10.9 h [10.1 to 12.2], P<0.001) and D1 groups (17.4 h [14.9 to 36], P=0.002). Postoperative cumulative IV morphine equivalent consumption at 24 h was significantly lower in the D2 group compared with control (P=0.014), but similar with D1 group (P=0.125). Postoperative VAS score at 24 h was also significantly lower in D2 group compared with control (P=0.024), but similar with D1 group (P=0.062). Compared with control, groups receiving dexamethasone experienced less sleep disruption on the first postoperative night (D1, P=0.035; D2, P=0.022, respectively). No significant elevations in blood glucose levels at 24 h in patients receiving dexamethasone (P=0.872). No patients reported block-related complications.
Conclusions: Coadministration of IV dexamethasone with IV dexmedetomidine significantly delayed the time to first rescue analgesic request after single-shot ISBPB in patients undergoing arthroscopic shoulder surgery.