Is dexmedetomidine superior to midazolam as a premedication in children? A meta-analysis of randomized controlled trials.

BACKGROUND In the current published literature, there are controversial results regarding the effectiveness of dexmedetomidine compared with midazolam as premedication in children. The aim of this meta-analysis was to compare the use of dexmedetomidine as a premedication in pediatric patients with that of midazolam. METHODS We searched for articles published in English that matched the key words 'dexmedetomidine', 'midazolam', and 'children' in the PubMed, Cochrane Library, Ovid, and Google Scholar databases. Additional studies were identified from the reference lists of the retrieved articles. Only prospective randomized controlled trials (RCTs) that compared the use of dexmedetomidine and midazolam as premedications in children were included. The extraction of data from the articles was performed independently by two authors using a predesigned Excel spreadsheet. The relative risks (RRs), weighted mean differences (WMDs), and their corresponding 95% confidence intervals (95% CIs) were calculated for dichotomous and continuous outcome data using the quality effects model of the MetaXL version 1.3 software. RESULTS Eleven prospective RCTs (829 children) met our criteria. Compared with midazolam, dexmedetomidine premedication was associated with more satisfactory sedation upon parent separation (eight RCTs [679 children]; RR: 1.25; 95% CI: 1.06, 1.46) and upon mask acceptance (seven RCTs [559 children]; RR: 1.17; 95% CI: 1.01, 1.36). During the postoperative period, premedication with dexmedetomidine lowered the numbers of requests for rescue analgesia (six RCTs [477 children]; RR: 0.55; 95% CI: 0.40, 0.74) and lowered the risks of agitation or delirium (seven RCTs with [466 children]; RR: 0.59; 95% CI: 0.40, 0.88), and shivering (three RCTs [192 children]; RR: 0.33; 95% CI: 0.18, 0.61). However, dexmedetomidine premedication reduced systolic blood pressure (three RCTs [242 children]; WMD: -11.47 mm·Hg(-1) ; 95% CI: -13.95, -8.98), mean blood pressure (three RCTs [202 children]; WMD: -5.66 mm·Hg(-1) ; 95% CI: -8.89, -2.43), and heart rate (six RCTs [444 children]; WMD: -12.71 beat·min(-1) ; 95% CI: -14.80, -10.62), and prolonged the onset of sedation (two RCTs [132 children] WMD: 13.78 min; 95% CI: 11.33, 16.23; I(2) = 0%) relative to midazolam. CONCLUSION This meta-analysis demonstrated that dexmedetomidine premedication is superior to midazolam premedication in terms of producing satisfactory sedation upon parent separation and mask acceptance. Dexmedetomidine premedication provides clinical benefits that included reducing the requirements for rescue analgesia and reducing agitation or delirium and shivering during the postoperative period. However, the risks of heart rate and blood pressure decreases, and the prolonged onset of sedation associated with dexmedetomidine should be considered.