Efficacy of furosemide for prevention of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses.

The research article evaluates how effective furosemide, a diuretic medication, is in preventing exercise-induced pulmonary hemorrhage (EIPH), a condition that causes bleeding in the lungs during strenuous exercise, in Thoroughbred racehorses.

Study Design and Methods

• The study was conducted as a randomized, placebo-controlled, crossover field trial. This means horses were randomly allotted to receive either the treatment (furosemide) or a placebo (saline solution) and then switched for the second trial.
• The research included 167 Thoroughbred racehorses. These horses participated in two races one week apart, with 9 to 16 horses in each race.
• Each horse received a dose of 500 mg of furosemide intravenously before one race, and a saline solution (placebo) before the other race. The order of treatments (i.e., whether they received the placebo or the drug first) was randomly determined.

Measure of Success

• After each race, the severity of EIPH in each horse was scored on a scale from 0 to 4 using tracheobronchoscopy, a procedure that visualizes the airways in the horse’s lungs.
• The data were then analyzed using various methods of multivariable logistic regression, a statistical analysis technique used to predict the outcome of a categorical dependent variable, in this case, the presence and severity of EIPH.

Key Findings

• The results revealed that horses were significantly more likely to develop EIPH, with severity score >or= 1 or moderate to severe EIPH (severity score >or= 2) following administration of saline solution than after receiving furosemide.
• Furthermore, out of the 120 horses that developed EIPH after receiving the saline solution, 81 (67.5%) showed a reduction in the severity of their EIPH score by at least one point when treated with furosemide.

Conclusions

• The study reveals that administering furosemide prior to racing effectively reduced both the incidence and severity of EIPH in Thoroughbred racehorses participating in races under typical conditions in South Africa.