Canine model of subglottic stenosis secondary to prolonged endotracheal intubation

Acquired subglottic stenosis is usually a consequence of prolonged endotracheal intubation. The present study describes a canine model of subglottis stenosis which is congruent with the known and suspected pathogenesis of the disease in man. Eighteen young pups (Canis familiaris) were used. A modified cuffed endotracheal tube was placed within the subglottis and secured by inflating the cuff. The capillary tube supplying the cuff was sealed and cut so as to lie below the epiglottis. Three animals died of tracheal rupture or collapse prior to or on the thirteen day following intubation. In the remaining animals, the cuffed tube was removed and the subglottis was examined. All exhibited ulcerations and exuberant polyploid granulations at the level of the subglottis and trachea. A 4 mm uncuffed endotracheal tube was introduced and secured within the subglottis and trachea of a number of the pups to provide an airway. After a 3-week period, the tube was removed and the dogs were sacrificed. Examination of the specimens showed various degrees of "hard" cicatricial stenosis of the subglottis and trachea. Histologic studies showed destruction of the cartilage with replacement by scar tissue and partial epithelialization. This model may be useful to investigations of the prevention and treatment of the disease.