Effects of lung site and fluid volume on results of bronchoalveolar lavage fluid analysis in horses

Abstract

Summary Bronchoalveolar lavage (bal) fluid was analyzed in healthy horses, using different lavage fluid volumes and lung sites. The only significant difference in the cellular composition of bal fluid between the right and left lungs was the mast cell numbers, which were significantly higher in the left lung. Total cell count ranged from 34 to 330 cells/μl for the right lung and 43 to 330 cells/μl for the left lung. Percentage of neutrophils ranged from 1 to 7% in the right lung and 1 to 5% in the left lung. The small-volume (50 ml) lavage had a greater percentage of neutrophils and a lesser percentage of mast cells in the large-volume (350 ml) lavage. Statistical difference in the composition of bal fluid recovered was not detected between the 3 sequential 100-ml lavages and a single 300-ml lavage, except that macrophages were significantly higher in the 3 sequential 100-ml lavages. Values for bal fluid analysis in healthy horses have varied considerably and this variation is from a failure to adhere to any standard technique for volume of fluid infused.