Histopathological changes in distal tracheal mucosa in beagle puppies.

Direct effects of the tracheotomy tube and cuff on glottic, subglottic and tracheal mucosa have been well described. Little work has been done on the effects of tracheotomy on the distal tracheobronchial tree. Ten beagle puppies underwent tracheotomy and were sacrificed at 18, 24, 36, 48 and 72 h. The trachea was studied for changes in cilia, epithelium, submucosal reaction and mucous production at the level of the tracheostome, tracheotomy tube tip, carina and right mainstem bronchus. Severe changes of epithelial erosion and ulceration with submucosal inflammatory reaction were noted as early as 18 h and persisted through 24 h. Some resolution of inflammation and progression to squamous metaplasia were seen at 36, 48 and 72 h. Changes in mucous gland activity varied widely. The traumatic effects of tracheotomy on normal tracheal anatomy and physiology and their clinical implications are discussed.