title: Management of the predicted difficult airway: a comparison of conventional blade laryngoscopy with video-assisted blade laryngoscopy and the GlideScope.
abstract: OBJECTIVE
  We investigated whether the use of two different video laryngoscopes [direct-coupled interface (DCI) video laryngoscope and GlideScope] may improve laryngoscopic view and intubation success compared with the conventional direct Macintosh laryngoscope (direct laryngoscopy) in patients with a predicted difficult airway.
  
  
  METHODS
  One hundred and twenty adult patients undergoing elective minor surgery requiring general anaesthesia and endotracheal intubation presenting with at least one predictor for a difficult airway were enrolled after Institutional Review Board approval and written informed consent was obtained. Repeated laryngoscopy was performed using direct laryngoscope, DCI laryngoscope and GlideScope in a randomized sequence before patients were intubated.
  
  
  RESULTS
  Both video laryngoscopes showed significantly better laryngoscopic view (according to Cormack and Lehane classification as modified by Yentis and Lee = C&L) than direct laryngoscope. Laryngoscopic view C&L >or= III was measured in 30% of patients when using direct laryngoscopy, and in only 11% when using the DCI laryngoscope (P < 0.001). The GlideScope enabled significantly better laryngoscopic view (C&L >or= III: 1.6%) than both direct (P < 0.001) and DCI laryngoscopes (P < 0.05). Clinically relevant improvement in the specific 36 patients with insufficient direct view (C&L >or= III) could be achieved significantly more often with the GlideScope (94.4%) than with the DCI laryngoscope (63.8%; P < 0.01). Laryngoscopy time did not differ between instruments [median (range): direct laryngoscope, 13 (5-33) s; DCI laryngoscope, 14 (6-40) s; GlideScope, 13 (5-34) s]. In contrast, tracheal intubation needed significantly more time with both video laryngoscopes [DCI laryngoscope, 27 (17-94) s, P < 0.05 and GlideScope, 33 (18-68) s, P < 0.01] than with the direct laryngoscope [22.5 (12-49) s]. Intubation failed in four cases (10%) using the direct laryngoscope and in one case (2.5%) each using the DCI laryngoscope and the GlideScope.
  
  
  CONCLUSIONS
  We conclude that the video laryngoscope and GlideScope in particular may be useful instruments in the management of the predicted difficult airway.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University-Hospital Schleswig-Holstein UKSH, Campus Kiel, Kiel, Germany. serocki@anaesthesie.uni-kiel.de
authors.forename: Götz
authors.initials: G
authors.lastname: Serocki
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein
authors.forename: Jens
authors.initials: J
authors.lastname: Scholz
authors.forename: Volker
authors.initials: V
authors.lastname: Dörges
mesh_terms: D000368:Aged; D000768:Anesthesia, General / Q000295:instrumentation* / Q000379:methods*; D004724:Endoscopy / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D014132:Trachea / Q000473:pathology; D014741:Video Recording