title: Assessment of upper airway anatomy in awake, sedated and anaesthetised patients using magnetic resonance imaging.
abstract: Magnetic Resonance Imaging was used to quantify the effects of 1. sedation and 2. general anaesthesia with a laryngeal mask airway (LMA) in place on the minimum antero-posterior (A-P) diameters of the naso-, oro- and hypopharynx and on the angle of the epiglottis relative to the adjacent posterior pharyngeal wall. Median sagittal T1-weighted images of the pharynx were obtained in 46 patients (16 awake, 14 sedated, 16 under general anaesthesia). In sedated patients, the A-P diameters of the pharynx were less than in awake patients, in particular at the levels of the epiglottis and soft palate. General anaesthesia and placement of a LMA was also associated with a reduced A-P diameter at the level of the soft palate, but with increased diameters at the levels of the tongue and epiglottis. Placement of a LMA caused abnormal downfolding of the epiglottis in most cases but this did not cause clinically significant airway obstruction.
authors.affiliation: Department of Anaesthesia, Sir Charles Gairdner Hospital, Perth, Western Australia.
authors.forename: G D
authors.initials: GD
authors.lastname: Shorten
authors.forename: N J
authors.initials: NJ
authors.lastname: Opie
authors.forename: P
authors.initials: P
authors.lastname: Graziotti
authors.forename: I
authors.initials: I
authors.lastname: Morris
authors.forename: M
authors.initials: M
authors.lastname: Khangure
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D001364:Awareness; D001933:Brain Stem / Q000033:anatomy & histology; D002552:Cerebral Ventricles / Q000033:anatomy & histology; D002574:Cervical Vertebrae / Q000033:anatomy & histology; D016292:Procedural Sedation; D004825:Epiglottis / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D007013:Hypopharynx / Q000033:anatomy & histology; D017214:Laryngeal Masks; D008279:Magnetic Resonance Imaging; D008297:Male; D008874:Midazolam; D008875:Middle Aged; D009305:Nasopharynx / Q000033:anatomy & histology; D009960:Oropharynx / Q000033:anatomy & histology; D010160:Palate, Soft / Q000033:anatomy & histology; D010614:Pharynx / Q000033:anatomy & histology*; D015742:Propofol; D013116:Spinal Cord / Q000033:anatomy & histology; D014059:Tongue / Q000033:anatomy & histology
chemical_list: D008874:Midazolam; D015742:Propofol