Association between post-extubation upper airway obstruction symptoms and airway size measured by computed tomography: a single-center observational study

BACKGROUND: Computed tomography (CT) is often performed to assess patients; however, little is known about how airway size measured by CT scan imaging might influence the occurrence of post-extubation upper airway obstruction. METHODS: This study aimed to evaluate the association between airway size measured by CT and the incidence of post-extubation upper airway obstruction symptoms for each sex. This single-center observational study was conducted at a tertiary emergency medical center/severe trauma center with a 12-bed intensive care unit. We enrolled consecutive adult patients (aged ≥ 20 years), who were intubated in the emergency room, between January 2016 and March 2019. Patients who underwent a CT scan of the glottic region within three hours before and after intubation were included in the analysis. For each sex, we first divided the patients into two groups: those who had post-extubation stridor, hoarseness, or both and those who had no such symptoms. Then, we compared the two groups using the Mann–Whitney U test and Fisher’s exact test. Univariate and multivariate logistic regression analyses were also performed. RESULTS: During the 39 months, 855 patients were enrolled in this study. A total of 217 patients underwent CT of the glottic region within three hours before and after intubation. Five patients had no records of symptoms after extubation. Thus, we analyzed data from 212 patients. This study included 144 males and 68 females. In female patients, the median [inter-quartile range] (average) of the transverse diameter of the glottis/endotracheal tube outer diameter (OD) ratio was smaller in patients with post-extubation upper airway obstruction symptoms than in patients without the symptoms (1.00 [1.00–1.00] (0.9572) vs. 1.00 [1.00–1.00] (1.00296), respectively; p = .013). Multivariate logistic regression analysis showed that the glottis/tube OD ratio < 1 was associated with the symptoms in females (odds ratio: 95% confidence interval, 5.68: 1.04–30.97). There was no relation between the airway sizes and the symptoms in male patients. CONCLUSIONS: In female patients, no gap between the endotracheal tube and the vocal codes or the glottic transverse diameter being smaller than the endotracheal tube OD on CT scan was associated with post-extubation upper airway obstruction symptoms.