Rabbit lung after acute smoke inhalation. Cellular responses and scanning electron microscopy.

The cellular responses in the lungs of rabbits and the morphologic features of the tracheobronchial tree by scanning electron microscopy were examined 24 hours following acute inhalation of Douglas fir wood smoke. Thermal injury to the upper airway was excluded. Injury to proximal tracheal lining cells was severe and consisted of loss of the epithelium. The changes of the epithelial barrier in the proximal major bronchi were less severe in nature. However, the alterations observed by scanning electron microscopy suggested dysfunction of the mucociliary blanket. Both cell counts of bronchoalveolar lavage fluid and morphologic findings reflected an increase in alveolar macrophage response. Smoke-exposed alveolar macrophages showed significant changes in the surface features. These findings may explain the tracheobronchitis seen clinically, and the propensity of patients to lung infection following smoke inhalation.