Effect of furosemide and furosemide-carbazochrome combination on exercise-induced pulmonary hemorrhage in Standardbred racehorses

The objective was to quantify the effect of furosemide and carbazochrome on exercise-induced pulmonary hemorrhage (EIPH) in Standardbred horses using red blood cell count and hemoglobin concentration in bronchoalveolar lavage (BAL) fluid. Six healthy Standardbred horses with prior evidence of EIPH performed a standardized treadmill test 4 h after administration of placebo, furosemide, or furosemide-carbazochrome combination. Red blood cell (RBC) counts and hemoglobin concentrations were determined on the BAL fluid. The RBC count in BAL ranges were (2903-26 025 cells/mu L), (45-24 060 cells/mu L), and (905-3045 cells/mu L) for placebo, furosemide, and furosemide-carbazochrome, respectively. Hemoglobin concentration ranges were (0.03-0.59 mg/mL), (0-01-0-55 mg/mL), and (0.007-0-16 mg/mL) for placebo, furosemide, and furosemide-carbazochrome groups, respectively. No significant differences were detected among treatments. However, there was great variability among horses, suggesting that a larger sample size or better selection of horses was needed.