Effect of intravenous dexmedetomidine and remifentanil on neonatal outcomes after caesarean section under general anaesthesia A systematic review and meta-analysis

BACKGROUND Various strategies have been used to mitigate haemodynamic instability during general anaesthesia for caesarean section. However, the safety of these strategies for neonates remains controversial. OBJECTIVE To investigate the effects of intravenous dexmedetomidine and remifentanil on neonatal outcomes during caesarean section under general anaesthesia. DESIGN Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES Databases of PubMed, EMBASE and CENTRAL were searched until March 2020 and updated in February 2021. ELIGIBILITY CRITERIA Randomised controlled trials were included if they compared dexmedetomidine and remifentanil infusion on neonatal outcomes after elective caesarean section under general anaesthesia. Primary outcomes were 1 and 5 min Apgar scores. Secondary outcomes were the incidence of neonatal mask ventilation or endotracheal intubation, and pH of the umbilical artery and vein. Studies that did not report primary outcomes were excluded. RESULTS Five studies with 258 patients in total were included. The Apgar score at 1 min in the remifentanil group was lower than that in the dexmedetomidine group for both quantitative [weighted mean difference (WMD): 0.75; 95% CI, 0.44 to 1.07; tau(2) = 0.00] and categorical outcomes (>= Apgar 7 vs. <Apgar 7) (risk ratio: 0.76; 95% CI, 0.59 to 0.99; tau(2) = 0.01). When trial sequential analysis (TSA) for Apgar score at 1 min was performed, the cumulative Z curve crossed both the conventional test boundary and the trial sequential monitoring boundary for the quantitative outcome but did not cross the trial sequential monitoring boundary for the categorical outcome. For both conventional meta-analysis and TSA, there were neither differences in the Apgar score at 5 min for either quantitative or categorical outcomes nor were there differences in the incidence of mask ventilation or intubation, or pH values of the umbilical artery and vein. CONCLUSION In our study, Apgar score at 1 min reported using both quantitative and categorical variables were lower in the remifentanil group than in the dexmedetomidine group but TSA showed that these differences were inconclusive for categorical variables. Data for other outcomes were scarce and did not allow any conclusions to be drawn. Thus, further studies with larger numbers of parturients and with neonatal outcomes as a primary endpoint are warranted to clarify the effects of intravenous dexmedetomidine and remifentanil.