Effect of frusemide on transvascular fluid fluxes across the lung in exercising horses.
Abstract: Frusemide (Fru) is widely prescribed for management of racehorses experiencing EIPH. The effect of Fru in the lung appears to be a reduction in transcapillary pressures and inhibition of the erythrocyte anion exchange, which may lead to attenuation of transpulmonary fluid fluxes during exercise. Objective: Treatment with Fru will attenuate transpulmonary fluid fluxes in horses during high intensity exercise. Methods: In a crossover study, 6 race-fit Standardbred horses were treated with 250 mg of Fru i.v. (FruTr) or placebo (Con) 4 h before exercise on a high speed treadmill until fatigue. Arterial and central mixed venous blood, as well as CO(2) elimination and O(2) uptake, were sampled. Volume changes across the lung and transvascular fluid fluxes were calculated from changes in haemoglobin, packed cell volume, plasma protein and cardiac output (Q). Results: During exercise, Q increased in both Con and FruTr, with Q being significantly lower in FruTr (mean ± s.e. 301.8 ± 8.5 l/min at fatigue) compared to Con (336.5 ± 15.6 l/min) (P<0.01). At rest frusemide had no effect on erythrocyte (J(ER)) and transvascular (J(V-A)) fluid fluxes across the lung. Exercise had a significant effect on J(ER) and J(V-A) (P ≤ 0.02). During exercise, J(ER) (at fatigue 14.6 ± 2.3 l/min and 11.6 ± 2.2 l/min in Con and FruTr, respectively) and J(V-A) (at fatigue 14.9 ± 2.3 l/min and 12.0 ± 2.2 l/min in Con and FruTr, respectively) were not significantly different between Con and FruTr (P = 0.6 and P = 0.8 for J(ER) and J(V-A), respectively). Conclusions: Fru does not have a measurable effect on J(ER) and J(V-A). Cardiac output was reduced in FruTr, suggesting that there were also smaller changes in the capillary recruitment and transvascular transmural hydrostatic pressures; however, this did not effect J(V-A). Therefore, Fru at the dose of 250 mg does not appear to be an effective treatment for regulating pulmonary transvascular forces during exercise in horses.
© 2010 EVJ Ltd.
Publication Date: 2010-09-29 PubMed ID: 21496074DOI: 10.1111/j.2042-3306.2010.00301.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study investigates the impact of frusemide, a commonly prescribed drug for racehorses experiencing Exercise-induced Pulmonary Hemorrhage (EIPH), on transpulmonary fluid fluxes during high-intensity exercise. It found that while frusemide did reduce cardiac output, it did not have a significant effect on fluid movement across the lung, indicating it may not be an effective treatment for regulating lung fluid during exercise.
Objective of the Study
- The study aimed to examine whether frusemide would reduce transpulmonary fluid fluxes in horses during high-intensity exercise. This was based on the hypothesis that frusemide reduces transcapillary pressures and suppresses erythrocyte anion exchange, which could reduce fluid movement across the lungs during intense physical activity.
Methods
- Carried out as a crossover study, which means each horse was used in multiple conditions, six race-fit Standardbred horses were chosen as subjects.
- Each horse was treated with a 250 mg intravenous dose of frusemide or a placebo four hours before exercising on a high-speed treadmill until fatigue.
- Various samples and measurements such as arterial and central mixed venous blood, CO2 elimination and O2 uptake were taken. Volume changes across the lung and transvascular fluid fluxes were determined using changes in haemoglobin, packed cell volume, plasma protein, and cardiac output (Q).
Results
- During exercise, cardiac output increased in both the control and frusemide-treated horses. Notably, it was significantly lower in the frusemide-treated horses.
- At rest, frusemide had no significant effect on the fluxes of erythrocytes (red blood cells) and transvascular fluids across the lungs.
- Contrary to the original hypothesis, during exercise, the fluxes of erythrocytes and transvascular fluids were not significantly different between control and frusemide-treated horses.
Conclusion
- Despite reducing cardiac output during exercise, frusemide did not affect the fluxes of erythrocytes and transvascular fluids across the lungs as expected.
- This indicates that a dose of 250 mg of frusemide may not be effective in controlling pulmonary transvascular forces during exercise in horses.
Cite This Article
APA
Vengust M, Kerr C, Staempfli HR, Pringle J, Heigenhauser GJ, Viel L.
(2010).
Effect of frusemide on transvascular fluid fluxes across the lung in exercising horses.
Equine Vet J, 43(4), 451-459.
https://doi.org/10.1111/j.2042-3306.2010.00301.x Publication
Researcher Affiliations
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia. modest.vengust@vf.uni-lj.si
MeSH Terms
- Animals
- Blood Proteins / metabolism
- Cardiac Output / physiology
- Cross-Over Studies
- Diuretics / administration & dosage
- Female
- Furosemide / administration & dosage
- Hematocrit / veterinary
- Hemoglobins / analysis
- Horses / physiology
- Lung / blood supply
- Lung / drug effects
- Lung / metabolism
- Male
- Physical Conditioning, Animal / physiology
- Pulmonary Circulation / drug effects
- Pulmonary Circulation / physiology
- Pulmonary Gas Exchange / drug effects
- Pulmonary Gas Exchange / physiology
Citations
This article has been cited 4 times.- Waller AP, Lindinger MI. Tracing Acid-Base Variables in Exercising Horses: Effects of Pre-Loading Oral Electrolytes. Animals (Basel) 2022 Dec 24;13(1).
- Lindinger MI, Waller AP. Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise. Animals (Basel) 2022 Jul 22;12(15).
- Frlic O, Seliškar A, Domanjko Petrič A, Blagus R, Heigenhauser G, Vengust M. Pulmonary Circulation Transvascular Fluid Fluxes Do Not Change during General Anesthesia in Dogs. Front Physiol 2018;9:124.
- Vengust M, Staempfli H, Viel L, Swenson ER, Heigenhauser G. Acetazolamide attenuates transvascular fluid flux in equine lungs during intense exercise. J Physiol 2013 Sep 15;591(18):4499-513.
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