Effects of dexmedetomidine as an adjuvant to ropivacaine or ropivacaine alone on duration of postoperative analgesia: A systematic review and meta-analysis of randomized controlled trials

Background Ropivacaine is a long-acting local anesthetic that is used to treat postoperative pain. Adjuvant use of dexmedetomidine in regional anesthesia may prolong the duration of analgesia. The objective of this systematic review and meta-analysis was to investigate the duration and effect of ropivacaine alone vs. ropivacaine in combination with dexmedetomidine for postoperative analgesia. Methods The PubMed, EMBASE, Web of Science, and Google Scholar databases were searched for randomized controlled trials (RCTs) of ropivacaine alone or ropivacaine in combination with dexmedetomidine for regional anesthesia. The primary outcome was duration of analgesia, defined as the time from onset of the block to the time of the first analgesic request or initial pain report. Secondary outcomes were duration of sensory block, duration of motor block, consumption of sufentanil for analgesia, length of hospital stay, and incidence of postoperative nausea and vomiting. Results Eighteen studies with 1148 patients were included. Overall quality of the RCTs, as assessed by the Jadad scale, was high. The meta-analysis demonstrated that ropivacaine combined with dexmedetomidine significantly prolonged the duration of postoperative analgesia from local anesthetics compared to ropivacaine alone (WMD: 4.14h; 95%CI: 3.29 similar to 5.0h; P<0.00001; I-2 = 99%). There was evidence of high heterogeneity between studies. The duration of sensory and motor block was significantly increased, and consumption of sufentanil for analgesia and the incidence of postoperative nausea and vomiting were significantly reduced in patients who received ropivacaine combined with dexmedetomidine compared to ropivacaine alone. There was no significant difference in length of hospital stay. Conclusions Compared to ropivacaine alone, ropivacaine combined with dexmedetomidine significantly prolonged the duration of postoperative analgesia and sensory and motor block, and reduced consumption of sufentanil for analgesia and the incidence of postoperative nausea and vomiting, across an array of surgeries.