Transversus Abdominis Plane Block With Dexmedetomidine and Local Anesthetics compared with Local Anesthetics Isolated for Patients Undergoing Cesarean Section: A Systematic Review and Meta-Analysis.

OBJECTIVES: Dexmedetomidine is a short-term sedative used for peripheral nerve blockade and spinal anesthesia. This meta-analysis evaluated efficacy and safety of dexmedetomidine in TAP block in C-section. METHODS: A systematic search across online databases comparing dexmedetomidine with local anesthetics to local anesthetics isolated in TAP block for women undergoing spinal anesthesia for cesarean section. Significance was defined at P<0.05 for odds ratios (OR), mean differences (MD), and standard mean differences (SMD). Heterogeneity weas evaluated using I² statistics. Twelve randomized controlled trials (RCTs) encompassing 799 patients were included. RESULTS: Dexmedetomidine delayed the consumption of first analgesic (MD 3.69; [95% CI 2.93-4.45]; P<0.00001; I²=86%) in the postoperative period; decreased the amount of rescue intravenous tramadol consumption (MD -13.61; [95% CI -24.56--2.67]; P=0.01; I²=85%), the number of patients who required rescue analgesic (OR 0.25; [95% CI 0.13-0.49]; P<0.00001; I²=42%) and the VAS scores at 6h (MD -1.48; [95% CI -1.65--1.30]; P<0.0001; I²=70%), at 12h (MD -0.92; [95% CI -1.60--0.24]; P=0.008; I²=90%) and at 24h (MD -0.50; [95% CI -0.93--0.08]; P=0.02; I²=92%). When patient satisfaction score was analyzed, there was also a significant difference between groups (SMD 1.07; [95% CI 0.76-1.39]; P<0.00001; I²=0%). DISCUSSION: Dexmedetomidine with local anesthetics was associated with a delay in consumption of the first analgesic in the postoperative period, decrease in the amount of rescue intravenous tramadol and in the VAS scores at 6, 12 and 24 hours. However, the GRADE assessment of the quality of evidence was 'low' due to the high risk of bias and heterogeneity.