Correlation between changes in thyromental distance and distance of migration of oral Ring-Adair-Elwyn tubes during neck extension with a shoulder positioner in patients undergoing neck procedures

Abstract

Objectives To measure the migration of oral Ring-Adair-Elwyn (RAE) preformed tracheal tubes during neck extension compared with the neutral neck position, and to assess the correlation between changes in the thyromental distance (TMD) during changes in neck position and tracheal tube migration. Methods This prospective observational study enrolled adult patients undergoing elective neck or thyroid procedures below the mandible. Using fibreoptic bronchoscopy, distances from the RAE tube adapter to the carina and to the tube tip were measured in the neutral position and after neck extension with a 10 cm D-shaped gel shoulder positioner. The change in distance of the RAE tube tip migration was compared with the change in TMD in each patient. Results This study enrolled 106 patients. During neck extension with a 10-cm shoulder positioner, RAE tubes cranially migrated 2.7 cm from the neutral position, but RAE tube migration was not correlated with the change in external TMD. Conclusion Oral RAE tube migration was not significantly correlated with the change in external TMD. Due to their large variability, changes in TMD were not useful predictors of RAE tube migration.