title: Rescue sedation with dexmedetomidine for diagnostic imaging: a preliminary report.
abstract: BACKGROUND
  Sedation is frequently required during noninvasive radiological imaging in children. Although commonly used agents such as chloral hydrate and midazolam are generally effective, failures may occur. The authors report their experience with dexmedetomidine for rescue sedation during magnetic resonance imaging.
  
  
  METHODS
  A retrospective chart review was undertaken.
  
  
  RESULTS
  The cohort included five patients ranging in age from 11 months to 16 years. Following the failure of other agents (chloral hydrate and/or midazolam), dexmedetomidine was administered as a loading dose of 0.3-1.0 microg x kg(-1) x min(-1) over 5-10 min followed by an infusion of 0.5-1.0 microg x kg(-1) x h(-1). The dexmedetomidine loading dose required to induce sedation was 0.78 +/- 0.42 microg x kg(-1) (range 0.3-1.2). The maintenance infusion rate was 0.57 +/- 0.06 microg x kg(-1) x h(-1) (range 0.48-0.69). The imaging procedures were completed without difficulty. No patient required additional bolus administrations or changes in the infusion rate. The duration of the dexmedetomidine infusion ranged from 30 to 50 min. The mean decrease in heart rate was 13.6 +/- 5.1 b x min(-1) (14.3 +/- 5.0% from baseline; P = 0.02), the mean decrease in systolic blood pressure was 26.4 +/- 15.2 mmHg (24.6 +/- 12.4% decrease from baseline; P = 0.004), and the mean decrease in respiratory rate was 1.4 +/- 1.5 min(-1) (7.5 +/- 7.9% decrease from baseline; P = NS). P(E)CO2 exceeded 6.5 kPa (50 mmHg) in one patient [maximum 6.6 kPa (51 mmHg)] with a maximum value of 6.0 +/- 0.4 kPa (46 +/- 3 mmHg). Oxygen saturation decreased from 98 +/- 1 to 95 +/- 1%; P = 0.001. No patient developed hypoxemia (oxygen saturation less than 90%). Mean time to recovery to baseline status was 112.5 +/- 50.6 min and time to discharge was 173.8 +/- 83.8 min.
  
  
  CONCLUSIONS
  Our preliminary experience suggests that dexmedetomidine may be an effective agent for procedural sedation during radiological imaging. Its potential application in this setting is discussed and other reports regarding its use in pediatric patients are reviewed.
authors.affiliation: Department of Child Health, The University of Missouri, Columbia, MO 65212, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Nichols
authors.forename: John W
authors.initials: JW
authors.lastname: Berkenbosch
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002697:Chloral Hydrate; D015331:Cohort Studies; D016292:Procedural Sedation; D020927:Dexmedetomidine; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006993:Hypnotics and Sedatives; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008874:Midazolam; D010100:Oxygen / Q000097:blood; D015656:Respiratory Mechanics / Q000502:physiology; D012189:Retrospective Studies
chemical_list: D006993:Hypnotics and Sedatives; D002697:Chloral Hydrate; D020927:Dexmedetomidine; D008874:Midazolam; D010100:Oxygen