. 2020 May 13;9:F1000 Faculty Rev-355. [Version 1] doi: 10.12688/f1000research.21914.1

Table 1. Examples of lower airway challenges.

Category	Example
Subglottic stenosis	Idiopathic subglottic stenosis and granulomatosis with polyangiitis
Tracheostomy and Montgomery T-tube management	Urgent or emergent versus elective tracheostomy. Long-term management interventions for tracheostomy or T-tubes such as replacement, upsizing or downsizing, and decannulation
Endoluminal, extraluminal, or mixed central airway obstruction	Bronchogenic carcinoma, goiter, mediastinal mass, etc.
Tracheal disruption	Traumatic tear or tumor
Bronchial disruption	Dehiscence of lung transplant anastomosis
Tracheal resection surgeries	Certain types and degrees of tracheal stenosis or tumor invasion
Tracheoesophageal fistula	Esophageal or bronchogenic cancer complications versus traumatic fistula
Bronchopleural fistula	Post-thoracic surgery
Less-common conditions	Tracheomalacia, tracheal reconstruction after an airway fire