Dexmedetomidine/propofol versus dexmedetomidine/ketamine versus dexmedetomidine as a sole agent for pediatric sedation during MRI

Propofol use in MRI procedures is growing worldwide especially for infants and children. Propofol causes unintended deep sedation and respiratory depression. The safety and efficacy of dexmedetomidine–propofol versus ketamine–dexmedetomidine versus dexmedetomidine alone as a based sedation regimen in specific age range of children is the study concern. The aim of this study is to compare the efficacy of dexmedetomidine/propofol mixture, dexmedetomidine/ketamine, and dexmedetomidine alone for pediatric MRI sedation. Ninty infants and children whose body weight is more than 10 kg were enrolled in a double-blind comparative study and assigned into three equal groups for sedation, group (DK) dexmedetomidine/ ketamine, group (DP) dexmedetomidine/propofol, and group (D) dexmedetomididne alone. All patients were given premedication in the form of oral midazolam 0.5 mg/kg 30 min before the procedure. Sedation was according to group: Group (DK) received ketamine 1.5 mg /kg intravenous bolus as a loading dose and maintenance dose done by dexmedetomidine infusion with a concentration of 0.004 mg/ml and infusion rate of 1 μg/kg/h for the first 10 min then reduced infusion dose to be in between 0.6 and 1 μg/kg/h to keep the patient sedated to a Ramsay sedation score more than 4. Group (DP) received propofol 1.5 mg/kg intravenous bolus as a loading dose, then maintenance dose infusion was a mixture of dexmedetomidine with a concentration of 0.004 mg/ml and propofol 4 mg/ml; this combination is compatible (Trissel et al., 2002 ; Cayo, 2013 ). This combination will be started by a loading dose of 1 μg/kg/h for the first 10 min then 0.6 to 1 μg/kg/h, sedated with a Ramsay sedation score of more than 4. Group (D) received dexmedetomidine with a dose of 2–3 μg/kg/h as loading for 10 min then 0.6 to 1 μg/kg/h to keep the patient sedated with a Ramsay sedation score of more than 4. There was a significant difference between the DP group induction recovery time, hemodynamics, and Ramsey sedation score up to 5 min after the induction to the other two groups, and there was a significant difference between the DK group to the other two groups concerning emergence phenomena (agitation, altered perception, hallucination) and sedation failure. The combination of dexmedetomidine to propofol with a low dose for sedation during MRI gives better induction + recovery time, improves hemodynamics, and decreases incidence of emergence phenomena and sedation failure.