Low-dose dexmedetomidine as an adjuvant to propofol infusion for children in MRI: A double-cohort study

Propofol is an effective sedative for magnetic resonance imaging. Nevertheless, it may cause hemodynamic and respiratory complications in a dose dependent fashion. We investigated the role of low-dose dexmedetomidine (0.5 μg/kg) as an adjuvant to propofol sedation for children undergoing magnetic resonance imaging. We hypothesized that dexmedetomidine would decrease the propofol dose required, airway complications, and hemodynamic instability.

We performed a retrospective chart review of patients' age of 1 month to 20 years. Children were divided into 2 groups; group P received only propofol; group D + P received intravenous bolus of dexmedetomidine (0.5 μg/kg) and propofol.

We reviewed 172 children in P and 129 in D + P (dexmedetomidine dose, median: 0.50 μg/kg (IQR: 0.45-0.62). An additional dexmedetomidine bolus was given to 17 children for sedation lasting longer than 2 hours. Total propofol dose (μg/kg/min) was significantly higher in group P than D + P; 215.0 (182.6-253.8) vs 147.6 (127.5-180.9); Median Diff = -67.8; 95%CI = -80.6, -54.9; P < .0001. There was no difference in recovery time (minutes); P: 28 (17-39) vs D + P: 27 (18-41); Median Diff = -1; 95%CI = -6.0, 4.0; P = .694. The need for airway support was significantly greater in P compared to D + P; 15/172 vs 3/129; OR = 0.25; 95%CI = 0.07 to 0.90; P = .02 (2-sample proportions test). Mean arterial pressure was significantly lower in P compared to D + P across time over 60 minutes after induction (coef = -0.06, 95%CI = -0.11, -0.02, P = .004).

A low-dose bolus of dexmedetomidine (0.5 μg/kg) used as an adjuvant can decrease the propofol requirement for children undergoing sedation for magnetic resonance imaging. This may decrease the need for airway support and contribute to improved hemodynamic stability without prolonging recovery time.