Lung function and morphology of dogs after sublethal exposure to nitrogen dioxide

Abstract

The relationship between respiratory function and morphological changes in 10 dogs exposed for 6 h to 69 ppm nitrogen dioxide was studied. Two additional dogs served as controls. Functional assessments included breathing pattern, breathing mechanics, forced expiration, gas exchange, and acid‐base status. Gross, microscopic, and ultrastructural evaluations were made of lung tissues from dogs killed at 0.1, 1.0, 2.0, 3.0, 7.0 and 14.0 d after exposure. Functional changes were similar to those reported for man. The principal dysfunction was gas‐exchange impairment, apparently resulting from foam in the airways. Breathing‐pattern alterations appeared to result from stimulation of neural receptors. Gas‐exchange measurements provided the most useful indicators of the pulmonary damage observed in this study.