Effect of Epidural Dexmedetomidine as an Adjuvant to Local Anesthetics for Labor Analgesia: A Meta-Analysis of Randomized Controlled Trials

Background. This study aims to determine the analgesic effect and safety of dexmedetomidine as an adjuvant to epidural local anesthetics during labor. Methods. Randomized controlled trials comparing epidural blocks with or without dexmedetomidine for labor analgesia were comprehensively searched. Review manager 5.4 was used to analyze the extracted data. Results. Compared with placebo and opioids, dexmedetomidine relieved labor pain of 15 min (P = 0.002), 30 min (P = 0.01), and 120 min (P = 0.02) after block and at the moment of fetal disengagement (P = 0.0002), decreased mean arterial pressure of 120 min (P = 0.01), heart rate of 30 min (P = 0.003), 60 min (P < 0.00001), and 120 min (P < 0.00001) after block, blood loss (P = 0.02), and the incidence of nausea/vomiting (P = 0.006), and increased the incidence of maternal bradycardia (P = 0.04). However, sensitivity analysis only found that the incidence of nausea/vomiting was significantly different. Compared with placebo, dexmedetomidine relieved labor pain of 30 min after block (P < 0.00001) and did not increase the incidences of side effects, but only two studies were enrolled. Compared with opioids, dexmedetomidine decreased the incidence of nausea/vomiting (P = 0.002), increased the incidence of maternal bradycardia (P = 0.04), and had a similar effect on labor pain relief; however, sensitivity analysis found that significant difference existed only at the incidence of nausea/vomiting. Other outcomes from meta-analysis or subgroup analysis were not different. Conclusions. Epidural dexmedetomidine has the potential to offer a better analgesic effect than placebo, similar labor pain control to opioids, and has no definite adverse effects on the parturient or fetus, but more high-quality studies are needed to confirm these conclusions.