A randomized trial evaluating low doses of propofol infusion after intravenous ketamine for ambulatory pediatric magnetic resonance imaging

Objective: Our study compared the discharge time after pediatric magnetic resonance imaging (MRI) following sedation with propofol infusion dose of 100, 75 and 50 mcg/ kg/min given after a bolus dose of ketamine and propofol. Materials and Methods: One hundred children of American Society of Anesthesiologists status 1/2, aged 6 months to 8 years, scheduled for elective MRI were enrolled and randomized to three groups to receive propofol infusion of 100, 75 or 50 mcg/kg/min (Groups A, B, and C, respectively). After premedicating children with midazolam 0.05 mg/kg intravenous (i.v.), sedation was induced with bolus dose of ketamine and propofol (1 mg/kg each) and the propofol infusion was connected. During the scan, heart rate, noninvasive blood pressure, respiratory rate, and oxygen saturation were monitored. Results: The primary outcome that is, discharge time was shortest for Group C (44.06 +/- 18.64 min) and longest for Group A (60.00 +/- 18.66 min), the difference being statistically and clinically significant. The secondary outcomes that is, additional propofol boluses, scan quality and awakening time were comparable for the three groups. The systolic blood pressure at 20, 25 and 30 min was significantly lower in Groups A and B compared with Group C. The incidence of sedation related adverse events was highest in Group A and least in Group C. Conclusion: After a bolus dose of ketamine and propofol (1 mg/ kg each), propofol infusion of 50 mcg/kg/min provided sedation with shortest discharge time for MRI in children premedicated with midazolam 0.05 mg/kg i. v. It also enabled stable hemodynamics with less adverse events.