[Efficacy and safety of intranasal dexmedetomidine premedication for children undergoing CT or magnetic resonance imaging: a systematic review and meta-analysis].

Objective: To review the efficacy and safety in children receiving intranasal dexmedetomidine premedication before CT or magnetic resonance imaging (MRI). Methods: A literature search (search terms included "dexmedetomidine" "intranasal drug administration" "children" "CT" and "MRI") was conducted using Embase, PubMed, the Cochrane Library, ClinicalTrials.gov, CNKI, Wanfang, VIP database and Chinese Biomedical Literature Database (searched from inception to March 18, 2019). Randomized controlled trials of children receiving intranasal dexmedetomidine versus chloral hydrate, ketamine or midazolam premedication before CT or MRI were included. The Cochrane Reviewers' Handbook 5.1.0 was used to evaluate the quality of the enrolled studies. The primary outcomes were sedation success rate and sedation induction time. The secondary outcomes included respiratory depression, heart rate, systolic blood pressure and blood oxygen saturation. Statistical analyses were performed using the Review Manager 5.3 software. Results: A total of 1 167 participants in 9 randomized controlled trials were included. The results of meta-analysis showed that intranasal dexmedetomidine premedication provided higher sedation success rate than oral chloral hydrate (relative risk (RR) =1.13, 95% confidence interval (CI) 1.02 to 1.26, P=0.020). There was no significant difference between intranasal dexmedetomidine and midazolam. In addition, the sedation induction time of intranasal dexmedetomidine group was significantly shorter than that in the oral chloral hydrate group (weighted mean difference -1.49, 95% CI -2.87 to -0.11; P=0.030), but showed no significant difference as compared with that of intranasal ketamine or midazolam. The patients treated with intranasal dexmedetomidine also showed significantly lower heart rate (RR=4.78, 95%CI 1.85-12.35, P=0.001) and less respiratory depression (RR=0.28, 95%CI 0.09-0.87, P=0.030). There were no intergroup differences in systolic blood pressure and blood oxygen saturation. Conclusions: Intranasal dexmedetomidine provided more effective sedation and higher safety in children undergoing CT or MRI. As this meta-analysis is limited by the small sample size, further high-quality randomized controlled trials are needed.