Laryngotracheal injury associated with nasotracheal intubation in the horse.

Laryngotracheal damage following short-term nasotracheal intubation was studied in 7 healthy horses. A flexible fiberoptic endoscope was used to examine the upper respiratory tract of each horse before nasal intubation with a cuffed silicone endotracheal tube and again at 1 hour, 24 hours, and 48 hours after extubation. Any abnormalities still evident at 48 hours were evaluated at 7 days after extubation. Mucosal damage involved the nasal meatus (5 of 7 horses), the arytenoid cartilages (5 of 7 horses), the trachea (5 of 7 horses), the dorsal pharyngeal recess (4 of 7 horses), the vocal folds (3 of 7 horses), and the entrance to the guttural pouch (3 of 7 horses). Laryngeal injury was attributable to tube pressure on the arytenoid cartilages and vocal folds. Tracheal damage appeared to be a function of pressure exerted by the inflated cuff on the tracheal mucosa.