Cell content in repetitive canine bronchoalveolar lavage.

To determine the effects and effectiveness of small volume (50 ml) bronchoalveolar lavage, lavages were performed on healthy mongrel dogs under a number of protocols. The differential and total cell counts in small volume bronchoalveolar lavages were determined. These factors were compared to those obtained by large volume (500 to 600 ml) lavage of the same segment in a second experimental group. Small volume lavage yielded a greater total cell count per milliliter and a greater concentration of polymorphonuclear leukocytes (PMNs) than large volume lavage, in which there was a somewhat higher concentration of bronchial cells. We compared the cell populations from lobes lavaged at 48-hour intervals. No significant changes in these populations or in pulmonary histology were noted. Our results suggest that small volume bronchoalveolar lavage provides a representative sample of the total free cell yield from the lower respiratory tract. Furthermore, small volume bronchoalveolar lavage performed at 48-hour intervals does not influence the distribution of these cells or significantly damage the pulmonary parenchyma.