Sedation Profile and Safety of Intravenous Dexmedetomidine for Procedural Sedation During MRI Brain in Paediatric Patients: A Prospective Observational Study

Abstract

Background: Procedural sedation for MRI brain in children demands an agent ensuring complete immobility, respiratory preservation, and rapid recovery. Dexmedetomidine, a selective α-2 adrenoceptor agonist producing natural sleep-like sedation, represents a compelling candidate for this indication.

Objectives: To assess the sedation profile and safety of intravenous dexmedetomidine (loading dose 1 mcg/kg over 10 minutes + maintenance 0.7–1.0 mcg/kg/hr) for procedural sedation during MRI brain in paediatric patients aged 1–10 years.

Methods: This prospective observational study enrolled 52 paediatric patients (ASA Grade I–II). Primary outcomes included time to onset of adequate sedation (Ramsay Sedation Score ≥ 4), recovery time, MRI image quality score, and requirement for propofol rescue. Serial haemodynamic parameters and adverse events were recorded at 10-minute intervals. Statistical analysis employed Friedman test, Wilcoxon signed-rank test, and Kruskal-Wallis test; p < 0.05 was considered significant.

Results: Mean age was 5.83 ± 2.17 years. Sedation onset was 6.59 ± 0.99 minutes with recovery at 11.25 ± 1.61 minutes. Optimal MRI quality score 1 was achieved in 47 patients (90.4%); 5 patients (9.6%) required propofol rescue and achieved MRI quality score 2. Procedural success rate was 100% with zero repeat scans. Heart rate declined significantly from 111.58 ± 9.00 to 94.92 ± 8.18 bpm at 20 minutes (Friedman χ² = 312.0, p < 0.001). SpO₂ remained clinically stable throughout the procedure, with no desaturation events. Adverse events were limited to 2 cases (3.8%) of self-limiting bradycardia.

Conclusion: Intravenous dexmedetomidine provides effective, safe, and rapidly reversible sedation for paediatric MRI brain with a 100% procedural success rate and no observed respiratory adverse events.