Intranasal dexmedetomidine as a single sedative agent for pediatric magnetic resonance imaging: a single-center...

Intranasal dexmedetomidine (IN DEX) is a non-invasive alternative to intravenous sedation, although it remains off-label in several countries, including Italy. This study evaluated the safety and efficacy of IN DEX for pediatric MRI sedation. In this monocentric retrospective observational study, patients < 18 years who received IN DEX (2-4 µg/kg) for MRI between June and November 2024 were included. Primary outcomes were adverse events and changes in vital parameters. Secondary outcomes included sedation times, procedural success, need for rescue sedation, and predictors of rescue therapy. A total of 109 patients were included (median age 10 months [IQR 3-31]). Three patients (2.8%) developed transient bradycardia and hypotension requiring fluid bolus. No respiratory depression occurred. Heart rate decreased significantly over time (p < 0.0001), while FiO₂ requirements increased slightly at later time points (p = 0.0006). Median time to sedation onset was 15 min (IQR 10-20) and time to full awakening 70 min (IQR 55-95). All MRI examinations were completed successfully. Rescue sedation was required in 40 patients (36.7%). In a multivariate analysis, longer time from sedation to MRI (OR 1.14, 95% CI 1.07-1.21), longer MRI duration (OR 1.04, 95% CI 1.00-1.07), and older age (OR 1.03, 95% CI 1.01-1.05) were associated with rescue therapy.

IN DEX provided effective pediatric MRI sedation with minimal hemodynamic events and no respiratory depression. Rescue sedation remained relatively frequent and was mainly associated with longer time from sedation to MRI, longer MRI duration and older age.

• Intranasal dexmedetomidine is increasingly used for pediatric MRI sedation because it avoids intravenous access and preserves respiratory drive. • Previous studies and meta-analyses report favorable safety profiles but heterogeneous success rates when used as a single sedative agent.

• In this real-world tertiary pediatric cohort, intranasal dexmedetomidine showed very low adverse events (2.8%) and no respiratory depression. • Older age, longer MRI duration, and longer sedation-to-MRI time were independently associated with rescue sedation.