Pathological changes in different parts of the larynx in canines following laryngeal burns induced by inhalation of hot air at various temperatures

Objective:To examine pathological changes in different parts of the larynx in canines after laryngeal burns induced by hot dry air at various temperatures and compare the pathological results with clinical typing. Methods: Eighteen healthy,male,adult dogs were randomly assigned to inhale hot dry air at 80 ℃(Group 1),160 ℃(Group 2) or 320 ℃(Group 3) for 20 min to induce inhalation injury.Pathological changes after hot air inhalation were examined at different locations of the larynx including the epiglottis,laryngeal vestibule,vocal folds and trachea. Results: Pathological changes were mainly characterized by local mucosal atrophy in the larynx in Group 1 and moderate edema in the laryngeal submucosa in Group 2. Group 3 showed two types of pathological changes in the larynx: severe edema as well as atrophy and charring. Conclusion: Due to its special anatomy and functions,the larynx has different responses to inhalation injuries induced by hot air at different temperatures. The pathological observation and analysis showed that the pathological changes brought about by laryngeal burns at 80 ℃and 160 ℃ were generally consistent with laryngoscopic manifestations of congestion and edema. Inhalation of hot dry air at 320 ℃ led to two types of pathological changes,severe edema and atrophy and charring. Hence,pathological analysis of laryngeal burns may be used as a supplemental tool to clinical typing.