Background: For optimum magnetic resonance imaging (MRI) image quality and to ensure precise diagnosis, patients have to remain motionless. We studied the effects of intranasal dexmedetomidine and ketamine with intravenous midazolam for pre-procedural and procedural sedation in school aged children.
Patients and methods: Children were randomly allocated to one of two groups: (Group D) received intranasal dexmedetomidine 3 μg kg(-1) and (Group K) received intranasal ketamine 7 mg kg(-1). Sedation levels 10, 20 and 30 min after drug instillation were evaluated using a Modified Ramsay sedation scale. A 4-point score was used to evaluate patients when they were separated from their parents and their response to intravenous cannulation.
Results: The two groups were comparable in terms of the child's anxiety at presentation (P = 0.245). We observed that Group K achieved faster sedation at 10 min point with P < 0.05. A comparable sedation score at 20 and 30 min were noted. The two groups were comparable regarding to the child's acceptance of nasal administration (P = 0.65). The sedation failure rate was insignificantly differ between groups (13.7% vs. 20.6% for Group D and K respectively). Heart rate and systolic blood pressure showed a significant difference between the two groups starting from the point of 20 min.
Conclusion: Intranasal dexmedetomidine 3 μg kg(-1) or ketamine 7 mg kg(-1) can be used safely and effectively to induce a state of moderate conscious sedation and to facilitate parents' separation and IV cannulation. Addition of midazolam in a dose not sufficient alone to produce the target sedation achieved our goal of deep level of sedation suitable for MRI procedure.
Keywords: Dexmedetomidine; MRI; intranasal pediatric sedation; ketamine.