Optimization of Subglottic View During Flexible Laryngoscopy With Patient Positioning

Abstract

Objective: Determine the ideal head position to optimize visualization of the subglottis using flexible laryngoscopy.

Study design: Prospective cohort study.

Setting: Outpatient multidisciplinary airway clinic at a tertiary care center.

Methods: Patients presenting to a multidisciplinary airway clinic undergoing nasoendoscopic airway examination were enrolled. Three head positions were utilized to examine the subglottis during laryngoscopy: "sniffing," chin tuck, and stooping positions. In-office reviewers and blinded clinician participants evaluated views of the airway based on Cormack-Lehane (CL) scale, airway grade (AG), and visual analog scale (VAS). Demographic data were obtained. Statistical analysis compared head positions and demographic data using Student's t test, analysis of variance, and Tukey's post hoc analysis.

Results: One hundred patients participated. No statistical differences existed among in-clinic or blinded reviewers for the CL score in any head position (p = .35, .5, respectively). For both AG and VAS, flexed and stooping positions were rated higher than the sniffing positions by both in-clinic and blinded reviewers (p < .01 for all analyses), but there was no statistical difference between these two positions (p = .28, .18, respectively). There was an inverse correlation between age and scores for AG and VAS in the flexed position for both sets of reviewers (p = .02, <.01 respectively), and a higher body mass index was significantly associated with the need to perform tracheoscopy for full airway evaluation (p < .01).

Conclusion: Both flexion and stoop postures can be implemented by an experienced endoscopist in awake, transnasal flexible laryngoscopy to enhance visualization of the subglottic airway.

Keywords: airway; in-office procedures; laryngoscopy; subglottis.