title: Does laryngoscopic view after intubation predict laryngoscopic view before intubation?
abstract: OBJECTIVE
  To determine if an endotracheal (ET) tube will distort the laryngeal view obtained with direct laryngoscopy measuring with the modified Cormack-Lehane scale (MCL).
  
  
  METHODS
  Observational single-arm study.
  
  
  METHODS
  The University of Calgary teaching hospitals.
  
  
  METHODS
  Patients between 18 and 86 years of age undergoing elective surgical procedures. A total of 173 patients were enrolled and analyzed.
  
  
  METHODS
  Direct laryngoscopy view obtained before ET intubation and directly after intubation.
  
  
  RESULTS
  The MCL scales were described for each view obtained and compared to each other with each patient serving as their own control. The primary objective was a change in the best obtainable view by direct laryngoscopy from an acceptable view (MCLS 1 or 2a) to an unacceptable view (MCLS 2b, 3, or 4) or changing from an unacceptable view (MCLS 2b, 3, or 4) to an acceptable view (MCLS 1 or 2a). The main finding of this study was that the ET tube altered the MCL in 58 (33%) of 173 patients, "worsening" the grade in 30 patients (17.34%) and "improving" the grade in 28 patients (16.18%).
  
  
  CONCLUSIONS
  We performed a prospective observational study to address the predictive value of postintubation laryngoscopy grade in adults. The presence of the ET tube both increased visualization of the glottis and worsened the view in different subjects. The important outcome was that the presence of the ET tube did in fact change the view obtained of the larynx during direct laryngoscopy. In conclusion, postintubation MCL grades may not be reliable to predict laryngeal grade and should be used with caution in the right clinical context.
authors.affiliation: Faculty of Medicine, The University of Calgary, Medical Class of 2016, 4212 Bowness Road NW, Calgary, AB T3B0A3, Canada. Electronic address: Jffoglia@ucalgary.ca.
authors.forename: Julena
authors.initials: J
authors.lastname: Foglia
authors.affiliation: Anesthesia Residency Program, C-229 Foothills Medical Centre, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada. Electronic address: David.Archer@albertahealthservices.ca.
authors.forename: David
authors.initials: D
authors.lastname: Archer
authors.affiliation: University of Calgary, Rockyview General Hospital, 7007 14 St SW, Calgary, AB T2V 1P9, Canada. Electronic address: pytkas2005@yahoo.ca.
authors.forename: Saul
authors.initials: S
authors.lastname: Pytka
authors.affiliation: South Health Campus, Calgary Health Region, 4448 Front Street, Calgary, AB T3M 1M4, Canada. Electronic address: Leyla.Baghirzada@albertahealthservices.ca.
authors.forename: Leyla
authors.initials: L
authors.lastname: Baghirzada
authors.affiliation: Department of Anesthesia, Foothills Medical Centre, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada. Electronic address: kaylene.duttchen@albertahealthservices.ca.
authors.forename: Kaylene
authors.initials: K
authors.lastname: Duttchen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017558:Elective Surgical Procedures; D005260:Female; D005931:Glottis / Q000033:anatomy & histology; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D007828:Laryngoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D055815:Young Adult
keywords: Airway management; Cormack-Lehane; Direct laryngoscopy; Intubation