title: Standard clinical risk factors for difficult laryngoscopy are not independent predictors of intubation success with the GlideScope.
abstract: OBJECTIVE
  To determine whether the first-attempt tracheal intubation incidence using the GlideScope videolaryngoscope is higher in patients with predicted increased risk of difficult laryngoscopy, and to assess the ability of other a priori defined standard risk factors to predict first-attempt intubation success, in aggregate and by forming scores.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Operating room in a tertiary-care academic center.
  
  
  METHODS
  357 patients intubated with the GlideScope for nonemergent general anesthesia.
  
  
  METHODS
  Mallampati airway class was used to create two groups of patients, one with higher and the other, lower, potential difficult laryngoscopy (Mallampati classes 3-4 and 1-2, respectively). Intubation success on the first attempt with the GlideScope videolaryngoscope in patients with a Mallampati class 3 or 4 airway versus those with Mallampati class 1 or 2 airway was tested. We also evaluated the predictive ability of the Mallampati airway class (1 and 2 vs 3 and 4) along with 9 other possible predictors of difficult intubation on first-attempt intubation success: gender, age, body mass index, level of training within our anesthesia residency program (Clinical Anesthesia Resident years 1, 2, and 3), ASA physical status, mouth opening, thyromental distance, neck flexion, and neck extension.
  
  
  RESULTS
  None of the standard predictors of difficult intubation was significantly associated with outcome after adjusting for other predictors. A multivariable model containing the aggregate set of variables predicted outcome significantly better than a risk score formed as the sum of 10 predictors ("Risk 10"; P = 0.0176).
  
  
  CONCLUSIONS
  With GlideScope-assisted tracheal intubation, Mallampati airway class is not an independent risk factor for difficult intubation. Other standard clinical risk factors of difficulty with direct laryngoscopy also do not appear to be individually predictive of first-attempt success of tracheal intubation.
authors.affiliation: Department of Cardiothoracic Anesthesiology, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH 44195, USA. diazj@ccf.org
authors.forename: José L
authors.initials: JL
authors.lastname: Díaz-Gómez
authors.forename: Anand
authors.initials: A
authors.lastname: Satyapriya
authors.forename: Sree V
authors.initials: SV
authors.lastname: Satyapriya
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Mascha
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Yang
authors.forename: Paul
authors.initials: P
authors.lastname: Krakovitz
authors.forename: Emad B
authors.initials: EB
authors.lastname: Mossad
authors.forename: Matthias
authors.initials: M
authors.lastname: Eikermann
authors.forename: D John
authors.initials: DJ
authors.lastname: Doyle
mesh_terms: D000046:Academic Medical Centers; D000367:Age Factors; D000768:Anesthesia, General / Q000379:methods; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods*; D008297:Male; D015999:Multivariate Analysis; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014741:Video Recording