title: Improved glottic exposure with the Video Macintosh Laryngoscope in adult emergency department tracheal intubations.
abstract: OBJECTIVE
  Glottic visualization with video is superior to direct laryngoscopy in controlled operating room studies. However, glottic exposure with video laryngoscopy has not been evaluated in the emergency department (ED) setting, where blood, secretions, poor patient positioning, and physiologic derangement can complicate laryngoscopy. We measure the difference in glottic visualization with video versus direct laryngoscopy.
  
  
  METHODS
  We prospectively studied a convenience sample of tracheal intubations at 2 academic EDs. We performed laryngoscopy with the Karl Storz Video Macintosh Laryngoscope, which can be used for conventional direct laryngoscopy, as well as video laryngoscopy. We rated glottic visualization with the Cormack-Lehane (C-L) Scale, defining "good" visualization as C-L I or II and "poor" visualization as C-L III or IV. We compared glottic exposure between direct and video laryngoscopy, determining the proportion of poor direct visualizations improved to good visualization with video laryngoscopy. We also determined the proportion of good direct visualizations worsened to poor visualization by video laryngoscopy.
  
  
  RESULTS
  We report data on 198 patients, including 146 (74%) medical, 51 (26%) trauma, and 1 (0.51%) unknown indications. All were tracheally intubated by emergency physicians. Postgraduate year 3 or 4 residents performed 102 (52.3%) of the laryngoscopies, postgraduate year 2 residents performed 60 (30.8%), interns performed 20 (10.3%), attending physicians performed 9 (4.6%), and operator experience and specialty were not reported in 4. Overall, good visualization (C-L grade I or II) was attained in 158 direct (80%) versus 185 video laryngoscopies (93%; McNemar's P<.0001). Of the 40 patients with poor glottic exposure on direct laryngoscopy, video laryngoscopy improved the view in 31 (78%; 95% confidence interval 62% to 89%). Of the 158 patients with good glottic view on direct laryngoscopy, video laryngoscopy worsened the view in 4 (3%; 95% confidence interval 0.7% to 6%).
  
  
  CONCLUSIONS
  Video laryngoscopy affords more grade I and II views than direct laryngoscopy and improves glottic exposure in most patients with poor direct glottic visualization. In a small proportion of cases, glottic exposure is worse with video than direct laryngoscopy.
authors.affiliation: Department of Emergency Medicine, Brigham and Women's Hospital, Boston, MA, USA. cabrown@partners.org
authors.forename: Calvin A
authors.initials: CA
authors.lastname: Brown
authors.forename: Aaron E
authors.initials: AE
authors.lastname: Bair
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Pallin
authors.forename: Erik G
authors.initials: EG
authors.lastname: Laurin
authors.forename: Ron M
authors.initials: RM
authors.lastname: Walls
mesh_terms: D000328:Adult; D000368:Aged; D004636:Emergency Service, Hospital; D005260:Female; D005931:Glottis; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000592:standards; D020704:Laryngoscopes / Q000592:standards; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014741:Video Recording / Q000379:methods