Bronchopulmonary lavage cytology in the dog: normal findings

Fiberoptic bronchoscopy was used to obtain cytologic specimens from all lung lobes of 9 normal Beagle dogs. Three specimen collection techniques (bronchial lavage, bronchial brushing and bronchial pinch biopsy imprints) and two staining procedures (Wright-Giemsa and Papanicolaou) were used and evaluated. Bronchial lavage was the most satisfactory technique for collection of samples from the deep lung and bronchial brushings were preferred for potential bronchial tree mural lesions. Wright-Giemsa was the stain of choice because mast cells could not be identified and eosinophilic leukocytes could be identified only with difficulty in Papanicolaou stained specimens. Total and differential cell counts were determined on all bronchial lavages from all lung lobes in order to establish baseline reference values. Total nucleated cell counts ranged from 260-120/microliters. There were no significant differences among mean total nucleated cell counts for the different lung lobes. Mean total nucleated cell counts were between 420 and 630 cells/microliters. Approximately 95% of all nucleated cells in normal lavages were undifferentiated alveolar macrophages. Most of the other cells seen were neutrophils, eosinophils, possible globule leukocytes and mast cells. Ciliated and nonciliated epithelial cells comprised less than 1% of the total nucleated cell population.