Principles of Subglottic and Tracheal Visualization with Transnasal Flexible Laryngoscopy

Area of Science:

• Otolaryngology
• Airway Imaging

Background:

• Transnasal flexible laryngoscopy (TFL) is effective for visualizing the subglottic area and trachea.
• Standardized documentation of these upper airway regions can be challenging.

Purpose of the Study:

• To develop a clinical grading system for TFL documentation of the subglottic area and trachea.
• To demonstrate principles for visualizing these critical airway segments in laryngology practice.

Main Methods:

• One hundred patients underwent TFL with both simple head extension (SHE) and flexion position (FP).
• Three laryngologists graded the subglottic and tracheal views obtained in each position.
• A paired t test compared visualization grades between SHE and FP, with inter-rater reliability assessed using kappa (k) scores.

Main Results:

• The flexion position (FP) resulted in significantly better visualization grades for the subglottic and tracheal areas compared to the simple head extension (SHE) position (P < 0.05).
• High inter-rater reliability was observed among the three laryngologists (k scores ranging from 0.757 to 0.785, P < 0.001).

Conclusions:

• A novel grading system facilitates objective assessment and documentation of the subglottis and trachea via TFL.
• The flexion position (FP) is recommended for optimal visualization of these upper airway structures during TFL procedures.