title: Upper airway size and configuration during propofol-based sedation for magnetic resonance imaging: an analysis of 138 infants and children.
abstract: BACKGROUND
  Propofol is widely used for pediatric sedation. However, increasing depth of propofol sedation is associated with airway narrowing and obstruction. The aim of this study was to objectively assess airway patency during a low-dose propofol-based sedation regimen by measuring upper airway size and configuration with magnetic resonance imaging (MRI) in spontaneously breathing infants and children.
  
  
  METHODS
  Magnetic resonance images of the upper airway were obtained in 138 infants and children, aged up to 6 years. Cross-sectional area, anteroposterior dimension, and transverse dimension were measured at the level of the soft palate, the base of the tongue, and the tip of the epiglottis. Sedation was induced with i.v. midazolam 0.1 mg·kg(-1) , nalbuphine 0.1 mg·kg(-1) , and propofol 1 mg·kg(-1) and maintained with propofol 5 mg·kg(-1) ·h(-1) .
  
  
  RESULTS
  Median (IQR) age was 36 (15, 48) months, and mean body weight was 13.7 ± 5.6 kg. Airway patency was maintained in all infants and children. The narrowest part of the pharyngeal airway was measured at the level of the base of the tongue. Anteroposterior dimensions were narrower than transverse dimensions in all age groups at all measurement sites. Transverse dimensions increased with age at all measurement sites, while anteroposterior dimensions did not increase comparably. No patient demonstrated respiratory or cardiovascular adverse events. All MRI were completed successfully without sedation failure.
  
  
  CONCLUSIONS
  Airway patency was maintained in all infants and children sedated with this low-dose propofol-based sedation regimen.
authors.affiliation: Department of Anesthesia, General Intensive Care and Pain Therapy, Medical University of Vienna, Vienna, Austria. anette-marie.machata@meduniwien.ac.at
authors.forename: Anette-Marie
authors.initials: AM
authors.lastname: Machata
authors.forename: Barbara
authors.initials: B
authors.lastname: Kabon
authors.forename: Harald
authors.initials: H
authors.lastname: Willschke
authors.forename: Daniela
authors.initials: D
authors.lastname: Prayer
authors.forename: Peter
authors.initials: P
authors.lastname: Marhofer
mesh_terms: D019412:Anatomy, Cross-Sectional; D002648:Child; D002675:Child, Preschool; D016292:Procedural Sedation; D004825:Epiglottis / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives; D007091:Image Processing, Computer-Assisted; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000008:administration & dosage; D010160:Palate, Soft / Q000033:anatomy & histology; D010614:Pharynx / Q000033:anatomy & histology; D015742:Propofol; D012137:Respiratory System / Q000033:anatomy & histology*; D014059:Tongue / Q000033:anatomy & histology
chemical_list: D006993:Hypnotics and Sedatives; D010100:Oxygen; D015742:Propofol