Clinical and ultrasonographic assessment of airway indices among non-pregnant, normotensive pregnant and pre-eclamptic patients: a prospective observational study

Background: Prediction of a difficult airway is of paramount importance for an anaesthesiologist. Various anatomical and physiological factors contribute to a difficult airway in pregnant females, especially those with pre-eclampsia. The aim of the study was to assess airway indices using both routinely used clinical methods and ultrasound.Methods: Fifty-five non-pregnant females, 55 normotensive pregnant females and 55 females with pre-eclampsia were included in this prospective study. Clinical airway assessment was the modified Mallampati score, thyro-mental distance, hyomental distance, hyomental distance ratio, chest circumference, neck circumference and chest-to-neck circumference ratio. Sonographic assessment included tongue width, tongue volume, anterior neck soft tissue thickness at the level of hyoid, epiglottis and vocal cords, subglottic diameter, ratio of pre-epiglottic space to anterior, posterior and midpoint of anterior and posterior vocal folds.Results: Several significant differences were observed between pregnant and non-pregnant females, with addi-tional changes in pre-eclamptic females. These included clinical parameters such as the modified Mallampati score and sonographic measurements of tongue width, tongue volume, subglottic diameter, anterior neck soft tis-sue thickness at the level of hyoid, epiglottis and vocal cords, and the ratio of pre-epiglottic space to anterior, pos-terior and midpoint of anterior and posterior vocal folds.Conclusion: Routinely used clinical methods of airway assessment lack sensitivity and specificity. Ultrasound can visualize anatomical structures in the supraglottic and subglottic views and is encouraging as an airway assess-ment tool.

Automated summary

The aim of this study was to assess airway indices using both routinely used clinical methods and ultrasound. The study found that the routinely used clinical methods lack sensitivity and specificity in airway assessment, while ultrasound can visualize anatomical structures in the supraglottic and subglottic views and is encouraging as an airway assessment tool.