ABSTRACT : Inducing sleep in epileptic patients is challenging, because antiepileptic drugs can cause significant pharmacokinetic and pharmacodynamic interactions with sedatives and anesthetics.This study was designed to compare the efficacy, incidence of adverse events, cardiovascular profile, respiratory profile and recovery profile following MRI sedation by propofol-ketamine(PK)infusion, propofol infusion(P) and dexmedetomidine (D)infusion in patients on antiepileptic therapy (AET)

METHODS : Ninety patients,on AET, aged up to 12 years, scheduled for elective brain MRI under sedation were enrolled. Anesthesia was induced by sevoflurane . SPO2, NIBP, HR and respiratory rate were monitored. Patients were randomized to receive infusion of PK ,P or D till the completion of MRI. If evidence of airway obstruction is present, supplemental airway maneuvering and interventions were instituted. Sedation levels were evaluated , if adequate sedation was not achieved after infusion , midazolam bolus were administred .Following sedation, observer was recording recovery time, complications and side effects during or after the anesthetic. ANOVA, repeated measure ANOVA and chisquare test were used for statistical analysis

RESULTS : : Patients on dexmedetomidine infusion had greater hemodynamic variation and recovery time than patients receiving propofol infusion and propofol-ketamine infusion. There was no significant variation in the respiratory parameters(RR, SPO2) in between groups. All patients on dexmedetomidine infusion required rescue midazolam

CONCLUSIONS : Dexmedetomidine infusion is ineffective as sole sedative in patients on AET undergoing MRI