Measurement of the lengths of different sections of the upper airway and their predictive factors.

Background: No studies have been conducted to define the lengths of the upper airway's different segments in normal healthy adults. Aims/Objectives: This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it. Material and methods: This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway. Results: The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm. Conclusion and significance: We concluded that a normal healthy adult's anterior subglottis length is 6.3–19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1–20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2–98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length. [ABSTRACT FROM AUTHOR]