title: Effect of jaw thrust and cricoid pressure maneuvers on glottic visualization during GlideScope videolaryngoscopy.
abstract: OBJECTIVE
  During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers have the potential to impact glottic visualization, including jaw thrust and cricoid pressure. The effect of these maneuvers on glottic visualization during videolaryngoscopy has not been studied. We evaluated the effect of jaw thrust and cricoid pressure maneuvers on both visualization of the glottis and the area of glottic opening visible during GlideScope-aided videolaryngoscopy.
  
  
  METHODS
  One hundred patients were enrolled in this study. After induction of general anesthesia, videolaryngoscopy was followed by jaw thrust and cricoid pressure maneuvers performed in random order. Laryngeal anatomy was recorded continuously and was saved as digital images following the initial laryngoscopy and after each maneuver. Glottis grade [modified Cormack and Lehane (C&L)] was recorded, as was the total glottic area.
  
  
  RESULTS
  There was improvement in glottis grade when utilizing jaw thrust maneuver in comparison to GlideScope videolaryngoscopy alone (31% improved, 4% worsened; P < 0.001). There was no difference in glottis grade when using the cricoid pressure maneuver in comparison with videolaryngoscopy alone (39% improved, 20% worsened; P = 0.19). Glottic opening area, however, was greater when utilizing the jaw thrust maneuver in comparison with videolaryngoscopy alone (P < 0.001), but smaller when utilizing the cricoid pressure maneuver in comparison with videolaryngoscopy alone (P < 0.001).
  
  
  CONCLUSIONS
  The jaw thrust maneuver was superior to videolaryngoscopy alone in improving the modified C&L grade and the visualized glottic area; however, no significant improvement was noted with cricoid pressure. We therefore recommend the use of jaw thrust as a first-line maneuver to aid in glottic visualization and tracheal intubation during GlideScope videolaryngoscopy.
authors.affiliation: Mayo Clinic College of Medicine, Jacksonville, FL, USA. corda.david@mayo.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Corda
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Riutort
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Leone
authors.forename: Mueez K
authors.initials: MK
authors.lastname: Qureshi
authors.forename: Michael G
authors.initials: MG
authors.lastname: Heckman
authors.forename: Sorin J
authors.initials: SJ
authors.lastname: Brull
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005931:Glottis / Q000033:anatomy & histology*; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation / Q000379:methods*; D007574:Jaw Relation Record; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011312:Pressure; D013957:Thyroid Cartilage / Q000502:physiology*; D014741:Video Recording