Effect of Adding Dexmedetomidine to Local Anesthetic Agents for Transversus Abdominis Plane Block A Meta-analysis

Background: Dexmedetomidine (Dex) has been used as an adjuvant in transversus abdominis plane (TAP) blocks. This meta-analysis was aimed at evaluating the effect of Dex in TAP blocks. Objectives: Outcome measures were total opiate consumption in 24 hours after surgery, time to systemic rescue analgesia, pain scores after surgery, and adverse events (AEs). Materials and Methods: Randomized controlled trials comparing Dex with local anesthetics to local anesthetics alone for analgesia after abdominal surgeries were included. Standardized mean difference (SMD) and mean difference (MD) were used for continuous variables and odds ratio for frequency data. Results: Analysis of data from 9 randomized controlled trials (598 patients) showed that the addition of Dex to LAs decreased opiate use in 24 hours after surgery (SMD, -3.07; 95% confidence interval [CI], -4.78 to -1.35), increased time to rescue analgesia (171.8 min; 95% CI, 112.34-231.26), and decreased pain scores (scale of 0 to 10) at 4 hours (MD, -0.36; 95% CI, -0.65 to -0.07) and 8 hours (MD, -0.17; 95% CI, -0.29 to -0.04) after surgery. Frequency of adverse events was similar between the 2 groups (odds ratio, 1; 95% CI, 0.61-1.63). The estimates for pain scores were prone to sensitivity analysis. The estimates for postoperative opiate use, time to rescue analgesia, and pain scores at 8 hours had significant heterogeneity. Conclusions: The addition of Dex to LAs in the TAP block for analgesia after abdominal surgeries decreased 24-hour opiate use and increased the overall time to rescue analgesia including certain subgroups without increasing adverse events. Its effect on postoperative pain scores was not as definitive.