A comparison of dexmedetomidine-midazolam with propofol for maintenance of anesthesia in children undergoing magnetic resonance imaging.
BACKGROUND
Dexmedetomidine is an alpha(2) agonist that is currently being investigated for its suitability to provide anesthesia for children. We compared the pharmacodynamic responses to dexmedetomidine-midazolam and propofol in children anesthetized with sevoflurane undergoing magnetic resonance imaging (MRI).


METHODS
Forty ASA 1 or 2 children, 1-10 yr of age, were randomized to receive either dexmedetomidine-midazolam or propofol for maintenance of anesthesia for MRI after a sevoflurane induction. Dexmedetomidine was administered as an initial loading dose (1 microg/kg) followed by a continuous infusion (0.5 microg x kg(-1) x h(-1)). Midazolam (0.1 mg/kg) was administered i.v. when the infusion commenced. Propofol was administered as a continuous infusion (250-300 microg x kg(-1) x min(-1)). Recovery times and hemodynamic responses were recorded by one nurse who was blinded to the treatments.


RESULTS
We found that the times to fully recover and to discharge from the ambulatory unit after dexmedetomidine administration were significantly greater (by 15 min) than those after propofol. Analysis of variance demonstrated that heart rate was slower and systolic blood pressure was greater with dexmedetomidine than propofol. Respiratory indices for the two treatments were similar. During recovery, hemodynamic responses were similar. Cardiorespiratory indices during anesthesia and recovery remained within normal limits for the children's ages. No adverse events were recorded.


CONCLUSIONS
Dexmedetomidine-midazolam provides adequate anesthesia for MRI although recovery is prolonged when compared with propofol. Heart rate was slower and systolic blood pressure was greater with dexmedetomidine when compared with propofol. Respiratory indices were similar for the two treatments.
Heard
Christopher
C
Department of Anesthesiology and Division of Pediatric Critical Care, State University of New York at Buffalo, Women and Children's Hospital of Buffalo, Buffalo, New York 14222, USA. heardop1@verizon.net
Burrows
Frederick
F
Johnson
Kristin
K
Joshi
Prashant
P
Houck
James
J
Lerman
Jerrold
J
D000758:Anesthesia / Q000191:economics; D001794:Blood Pressure / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D020927:Dexmedetomidine / Q000008:administration & dosage*; D005260:Female; D017048:Health Care Costs; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008874:Midazolam / Q000008:administration & dosage*; D015742:Propofol / Q000494:pharmacology*; D012119:Respiration / Q000187:drug effects
D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine; D008874:Midazolam; D015742:Propofol