Pulmonary capillary pressure during exercise in horses.
Abstract: The object of this study was to relate pulmonary capillary pressure to arterial and wedge pressures during exercise. Pulmonary vascular pressures were measured in six standardbred horses exercising at speeds equivalent to 75, 90, and 100% of maximal heart rate. Vascular pressures were measured with transducer-tip catheters and expressed relative to esophageal pressure. Pulmonary capillary pressure was estimated by the arterial-occlusion technique modified for exercise. Mean pulmonary arterial, capillary and wedge pressures increased from 30.5 +/- 6.3, 17.8 +/- 4.3, and 13.4 +/- 1.6 mmHg, respectively, at rest, to 70.5 +/- 5.2, 42.1 +/- 5.3, and 38.4 +/- 5.6 mmHg, respectively, at maximal exercise. The largest part of the increase occurred during the first level of exertion. With exercise, the pressure across the lung barely doubled at a time when the cardiac output would have increased at least fivefold. Thus the absolute resistance in both pre- and postcapillary segments must have decreased. The capillary and wedge pressures rose similarly, whereas the difference between them did not change with exertion. The fractional resistance of the precapillary segment increased with exercise. The postcapillary resistance, initially 28% of the total pulmonary vascular resistance, fell to 9% at maximal exercise. The rise (to approximately 45 mmHg) in pulmonary capillary pressure with exertion is consistent with an increase in transvascular filtration.
Publication Date: 1996-05-01 PubMed ID: 8727568DOI: 10.1152/jappl.1996.80.5.1792Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research study aimed to understand the relationship between pulmonary capillary pressure and arterial and wedge pressures during exercise in horses. The findings suggest that the resistance in both pre- and postcapillary segments decrease during exercise, implying increased transvascular filtration.
Methodology
- The study was conducted on six standardbred horses.
- These horses were exercised at speeds corresponding to 75, 90, and 100% of their maximal heart rate for collecting valid readings.
- Pulmonary vascular pressures were measured using transducer-tip catheters and were expressed relative to esophageal pressure.
- Pulmonary capillary pressure was estimated by a method known as the arterial-occlusion technique, modified specifically for exercise.
Findings
- On comparing the systolic and diastolic pressures, it was found that pulmonary arterial, capillary, and wedge pressures increased from their resting state during exercise.
- The major part of this increase happened during the initial level of exertion itself.
- It was also noted that the pressure across the lung barely doubled at a time the cardiac output would have increased at least fivefold. This suggests that the absolute resistance in both pre- and postcapillary segments must have decreased during exercise.
- However, the capillary and wedge pressures rose in a similar pattern. The difference between them remained unaffected by exertion adding to the peculiar findings of the study.
- The study also found that the fractional resistance of the precapillary segment increased with exercise. On the contrary, the postcapillary resistance which was initially 28% of the total pulmonary vascular resistance, dropped to 9% during maximal exercise. This could also suggest that the total pulmonary vascular resistance decreases during high-intensity exercise.
- Importantly, the study also noted a rise in pulmonary capillary pressure with exertion. This rise is consistent with an increase in transvascular filtration, which is a crucial physiological response during exercise.
Conclusion
- The research provides insightful understanding about the changes in pulmonary capillary pressure and its relation to arterial and wedge pressures during exercise.
- Though this study was conducted on horses, it sheds light on the dynamics of blood pressure and heart functioning during exercise in large mammals that could potentially be applied in understanding human physiology as well.
Cite This Article
APA
Sinha AK, Gleed RD, Hakim TS, Dobson A, Shannon KJ.
(1996).
Pulmonary capillary pressure during exercise in horses.
J Appl Physiol (1985), 80(5), 1792-1798.
https://doi.org/10.1152/jappl.1996.80.5.1792 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca 14853, New York, USA.
MeSH Terms
- Animals
- Capillaries / physiology
- Heart Rate / physiology
- Horses
- Physical Conditioning, Animal
- Pressure
- Pulmonary Circulation / physiology
- Time Factors
Citations
This article has been cited 7 times.- 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.
- Kim DS, Lee M, Kwon OJ, Jeong I, Son JW, Na MJ, Kwon SJ. A 45-Year-Old Man With Recurrent Dyspnea and Hemoptysis during Exercise: Exercise-Induced Pulmonary Hemorrhage/Edema. Tuberc Respir Dis (Seoul) 2015 Oct;78(4):375-9.
- 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.
- Vengust M, Staempfli H, Viel L, Heigenhauser G. Transvascular fluid flux from the pulmonary vasculature at rest and during exercise in horses. J Physiol 2006 Jan 15;570(Pt 2):397-405.
- Hackett RP, Ducharme NG, Gleed RD, Mitchell L, Soderholm LV, Erickson BK, Erb HN. Do Thoroughbred and Standardbred horses have similar increases in pulmonary vascular pressures during exertion?. Can J Vet Res 2003 Oct;67(4):291-6.
- Boesch JM, Gleed RD, Buss PE, Tordiffe ASW, Zeiler GE, Miller MA, Viljoen F, Harvey BH, Parry SA, Meyer LCR. Etorphine induces pathophysiology in immobilized white rhinoceros through sympathomimesis that is attenuated by butorphanol. Conserv Physiol 2025;13(1):coaf009.
- Bayly WM, Leguillette R, Sides RH, Massie S, Guigand C, Jones KB, Warlick LM, Thueson EL, Troudt TA, Slocombe RF, Jones JH. Equine exercise-induced pulmonary hemorrhage: the role of high left-heart pressures secondary to exercise-induced hypervolemia, and high inspiratory pressures. J Appl Physiol (1985) 2024 Nov 1;137(5):1359-1373.
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