Effectiveness of Dexmedetomidine vs Ketamine in Paediatric Patients Undergoing MRI

Introduction: Magnetic Resonance Imaging (MRI) is not painful, but frightening especially in children leading to movement and artefacts causing prolongation of the procedure. Though analgesia is not required, but being a noisy suite, deep sedation is a prerequisite for it. Dexmedetomidine (DEX) and Ketamine both anaesthetic drugs can achieve the sedation in the children but never had been compared. Aim: To compare the effect of DEX and Ketamine in paediatric patients undergoing MRI under sedation. Materials and Methods: This was a cross-sectional study carried out from August 2017 to July 2018 included 74 patients. All patients were separated into Group K for Ketamine (loading dose of 1 mg/kg, intravenous over 10 min followed by infusion of 10-15 mcg/kg/min) and Group D for DEX (loading dose of 1 mcg/kg over 10 min followed by infusion of DEX at 0.2-0.7 mcg/kg/h). Ramsay sedation score of five was considered as onset of sedation. Midazolam 0.1 mg/kg IV was decided as rescue sedation. Unpaired t-test was applied for the continuous variables. Results: Sixty-one patients were analysed, 31 in Group K, and 30 in Group D. The onset time for sedation in Group K was 6.30±1.32 minutes and 12.20±SD=2.01 minutes in Group D which was significantly shorter in Group K (p=0.001). However, the time to Modified Aldrete Score of 10/10 was higher in Group K (21.10±1.84 minutes) vs (13.73±1.89 minutes) in Group D which is statistically significant. (Mean±SD; p=0.001). No adverse events were reported in both the groups. Conclusion: Ketamine and DEX can both be used for MRI sedation in children successfully without any adverse effects. The onset of sedation is faster in Ketamine, but discharge and recovery are significantly delayed with Ketamine as compared