The evaluation of the trachea as a new parameter in determining the prognosis of COVID-19: first pilot study

Coronavirus disease-2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) follows a biphasic disease model consisting of an early viral response phase and an inflammation phase. SARS-CoV-2 has a high affinity for the upper respiratory tract and conjunctiva; hence, it can infect the upper respiratory tract and facilitate airway inflammation. COVID-19 also affects the tracheal epithelial cells. We hypothesized that the size of the trachea increases depending on the severity of the disease, and this increase is an indicator of poor prognosis. There are no studies on this subject in literature, to the best of our knowledge. For this purpose, in this study, the tracheas of 326 patients who reported to the radiology clinic were examined by evaluating the thoracic computed tomography (CT) images.

The patients who were admitted to the Malatya Training and Research Hospital between September and December 2020, had a positive SARS-CoV-2 nasopharyngeal reverse transcription-polymerase chain reaction result, and had undergone thoracic CT, were included in the study. The thoracic CT scans without respiratory artifacts were evaluated, and anteroposterior (AP) and transverse diameters of the trachea were measured at the thyroid and bifurcation levels.

We believe that a tracheal AP diameter of >20 mm at the thyroid level and a tracheal AP diameter of 18 mm at the thyroid bifurcation level (according to Group 3 and Group 4) may be indicators of poor prognosis. In terms of survival, a tracheal AP diameter of >18 mm at the bifurcation level can be considered as a poor prognostic factor.

The tracheal diameter may increase in proportion to the severity of inflammation, indicating or accompanying a poor prognosis. Patients with extensive involvement should be monitored closely for the development of tracheal stenosis.