Prediction of narrowest infraglottic central airway diameter on computerized tomography in adult patients

Introduction: The internal dimensions of the infraglottic airway can be determined accurately by CT scans. Although height is the primary determinant of airway size, no tool exists to predict the narrowest dimension of the infraglottic central airway in adults. Objectives:  This study measured Antero Posterior Diameter (APD), and Transverse Diameter (TD) of the infraglottic airway in adult patients from CT scans, and correlated these with the demographic characteristics to develop a prediction model for narrowest dimension of the infraglottic central airway in adults. Methods: This retrospective cross-sectional study analyzed CT scan images of the neck and thorax in 200 adult onco-surgical patients. The APD and TD of the infraglottic airway were measured at eight levels below the vocal cords. A statistical model for predicting the narrowest dimension of the infraglottic central airway based on gender and height was developed. Results: The smallest TD was recorded at 5 mm below the vocal cords for both males and females. Gender and height were the most significant predictors of these internal dimensions. The linear regression model based on approximation of the Random Forest and tuned XGBoost models demonstrated high accuracy predictive performance, with an R² of 0.9993 and a root mean squared error (RMSE) value of 0.00275 mm. Conclusion:  The narrowest infraglottic airway diameter can be reliably estimated from patient height and sex using the derived linear model. These findings provide a basis for anatomical prediction of tracheal dimensions and may support future development of individualized airway assessment tools.